Part III. Processes of Reproducing Illustrations.

Methods employed 72

Photoengraving 72

General features 72

Zinc etching 73

Copper etching in relief 75

Half-tone engraving 75

Three-color half-tone process 78

Wax engraving (the cerotype process) 80

Wood engraving 81

Photogelatin processes 82

Lithography 83

Original process 83

Photolithography 86

Offset printing 87

Chromolithography 87

Engraving on stone and on copper 89

Appendix.

Length of degrees of latitude and longitude 91

Metric system and equivalents 92

Geologic eras, periods, systems, epochs, and series 92

Chemical elements and symbols 93

Greek alphabet 93

Roman numerals 93

Mathematical signs 94

Names of rocks 94

ILLUSTRATIONS.

Page.

Plate I. Methods of inserting plates and figures 10

II. Symbols used on geologic maps, economic maps,

and mine plans 20

III. Lithologic symbols used in structure and columnar

sections to represent different kinds of rock 32

IV. Symbols used on base maps 52

V. Reduction sheet used in lettering illustrations 54

VI. Half-tone prints showing effects produced by the

use of six standard screens 56

VII. Details of the make-up of a geologic map 58

VIII. Patterns used to show distinctions between areas

on black and white maps 60

IX. Diagrams and curves 64

Figure 1. Diagrams showing principal, guide, and auxiliary

meridians, standard and special parallels and

correction lines, and system of numbering

townships, ranges, and sections 16

2. Conventional lines used in preparing plans and

diagrams of mine workings to distinguish

different levels 29

3. Section and perspective view showing relations

of surface features to the different kinds of

rocks and the structure of the beds 30

4. Sections of coal beds 31

5. Diagram illustrating method of projecting a map 44

6. Methods of expressing relief by contour lines,

by hachures, by shading on stipple board, and

by a brush drawing 49

7. Designs for bar scales 60

8. Method of making a bar scale for a map of

unknown scale 60

9. Map bearing six areal line patterns 62

10. Diagram showing method of marking maps for

reduction or enlargement (for record) 64

11. Structure section showing method of determining

the succession of folds 65

THE PREPARATION OF ILLUSTRATIONS FOR REPORTS OF THE United STATES

GEOLOGICAL SURVEY.

By John L. Ridgway.

PART I. PREPARATION BY AUTHORS.

INTRODUCTION.

There has been an obvious need in the Geological Survey of a paper

devoted wholly to illustrations. No complete paper on the character,

use, and mode of preparation of illustrations has been published by

the Survey, though brief suggestions concerning certain features of

their use have been printed in connection with other suggestions

pertaining to publications. The present paper includes matter which it

is hoped will be of service to authors in their work of making up

original drafts of illustrations and to draftsmen who are using these

originals in preparing more finished drawings, but it is not a

technical treatise on drafting.

The effectiveness of illustrations does not depend entirely on good

drawings nor on good reproduction; it may be due in large part to the

inherent character of the rough material submitted. If this material

is effective or striking the finished illustrations, if well made,

will be equally effective and striking. Each step in the making of an

illustration--first the preparation of the author's original or rough

draft, next the final drawing, and last the reproduction--is closely

related to the others, and each is dependent on the others for good

results. If the material has been well handled at all three steps the

resulting illustration should be above criticism; if it has been

poorly handled at any one of the three the effectiveness of the

illustration is either impaired or ruined.

A consideration of processes of reproduction is essential in the

preparation of all illustrations, and the influence or effect of the

process to be selected on the methods of preparing a drawing has

seemed to warrant the presentation of brief descriptions of the

processes usually employed by the Geological Survey. These

descriptions include statements as to the kind of copy that is

suitable for each process, the result produced by each, and the

relative cost of the processes.

PURPOSE AND VALUE OF ILLUSTRATIONS.

An illustration in a report of the Geological Survey is not merely a

picture having a remote bearing on the subject matter of the report;

it must represent or explain something discussed or mentioned in order

to become an illustration in the true sense of the term. The

illustrations used in the Survey's reports are not employed for

embellishment; the more pictorial kinds may be in some measure

decorative, but decoration is distinctly not their primary purpose.

The illustrations used in popular literature are designed to meet a

public demand for ornament or attractiveness. Those used in scientific

publications should be made plain and direct, without attempt to

ornament or beautify. In the literature of science illustrations made

by the reproduction of photographs or of explanatory diagrams or maps

are intended simply to furnish greater illumination, and if the

illustrations display photographic reality most statements or

conclusions thus illuminated seem less open to dispute. A photograph

may thus serve the double purpose of explanation and corroboration.

The graphic expression of data and of details in a Survey report is

intended to aid the reader in comprehending the report, and this is

the prime advantage of its use, but it also enables the writer to omit

from his text numerous descriptive details. It would generally be

difficult without illustrations to present a clear picture of the

geology of a region in its exact relations, and especially to describe

adequately the form and the details of the structure of many fossils.

The tasks of both the writer and the reader of reports on geology and

kindred subjects are thus greatly facilitated by geologic maps,

sections, paleontologic drawings, and illustrations of other kinds.

The responsibility for good and effective illustrations rests largely

upon the author, who should select and plan his illustrations with a

view to their utility in aiding the reader to understand his report.

SELECTION AND APPROVAL OF ILLUSTRATIONS.

There is no rule limiting the number of illustrations that may be used

in a publication of the Geological Survey, but in selecting

illustrations for a report an author may easily fall into the error of

over-illustration. The number of diagrammatic drawings or of drawings

that express the author's deductions is rarely in excess of the needs

of a paper, but the number of photographs submitted is often

excessive. The number of pages in a manuscript may be a factor in

determining the proper number of illustrations, but as the need of

illustrations varies greatly from paper to paper this factor alone is

not decisive. The tendency to overillustrate led the Director to issue

the following order[1] governing the approval of illustrations:

[Footnote 1: From Survey Order 63, Oct. 20, 1915.]

The primary responsibility for the selection of illustrative

material shall rest upon the author and the chief of the

branch transmitting the report: No one knows the subject

matter of the report better than its author, though a

sympathetic critic is usually needed to correct the personal

equation that may express itself In an excessive number of

illustrations or the use of photographs into which no one but

the field man himself can read what he wishes to illustrate.

The approval by the chief of branch of the illustrations

selected by the author will be taken as vouching for those

illustrations as essential and adequate, and the scientific

value of the illustrations will not be subject to review in

the section of illustrations.

The chief of the section of illustrations shall decide the

technical questions relating to the preparation of these

illustrations for reproduction and may recommend the

rejection of any that do not promise effective or economical

reproduction. In the consideration of such questions,

especially any relating to maps, the cooperation of the

editor of geologic maps and chief engraver will be expected.

The judgment of an author as to the illustrative value of a photograph

is likely to be biased by his knowledge of the features that are

actually included in the view represented, not all of which may be

shown clearly in the photograph; his knowledge of all the features

enables him to see more in his picture than his readers will be able

to recognize without detailed description. Photographs in which

special or significant features are obscured by foliage or lost in

hazy distance do not make acceptable illustrations, and the use of a

picture that requires much description to make it illustrate reverses,

in a measure, the relations of text and illustrations.

A photograph is not necessarily good for reproduction simply because

it shows some particular feature to be illustrated; the quality of the

print it will afford when reproduced from an engraved plate should

also be considered. Some loss of detail by reproduction must be

expected, and therefore only the clearest and most effective prints

obtainable should be submitted.

If an author has difficulty in making his preliminary or "original"

drawings he may request that a draftsman be detailed to aid him. The

request should be made to the Director through the chief of branch and

properly approved. The work will then be done in the section of

illustrations as advance preparation, but finished drawings should not

be thus prepared unless the conditions are unusual. The administrative

geologist reviews all illustrations submitted and represents the

Director in matters relating to illustrations.

SUBMITTAL OF ILLUSTRATIONS.

All material intended for illustrations, except paleontologic

specimens, should be submitted with the manuscript of the paper to be

illustrated but in a separate package marked "Illustrations to

accompany a paper on ---- by ----." The package should contain a

carbon copy of the list of illustrations that accompanies the

manuscript or, if the titles to be printed on or with the

illustrations include fuller descriptions than are given in that list,

a carbon copy of the list giving complete titles and descriptions, the

original of which should also accompany the manuscript. In the list

each plate and figure should be separately numbered consecutively in

the order in which it should appear in the report, and a figure

opposite each title should show the number of the manuscript page on

which the illustration is first mentioned or most fully discussed.

Roman numerals should be used for the plates and arabic numerals for

the figures. Each drawing or photograph should bear, in addition to

the number and title, any suggestions concerning preparation,

reduction, and method of reproduction which the author may consider

especially desirable. The list should be headed "Illustrations."

Specimens other than fossils that are to be illustrated must be

submitted directly to the section of illustrations, but the author may

first obtain photographic prints of them in order to make up his

plates. The specimens should be carefully packed and any that are

fragile should be so marked.

KINDS OF ILLUSTRATIONS.

The illustrations in reports of the Geological Survey may be

classified into five more or less distinct groups--(1) maps, (2)

diagrams (including graphs, sections, plans, figures of apparatus, and

stereograms), (3) outdoor photographs, (4) photographs and drawings of

specimens, and (5) sketches. These may be further divided into two

large groups, which may be called permanent and ephemeral. The

permanent group includes illustrations that do not lose value through

lapse of time or by natural alteration, such as detailed geologic

maps, well-prepared structure sections, views of specimens, and good

photographs or drawings of natural phenomena; the ephemeral group

includes maps showing progress, key maps, diagrams showing yearly

production, and many others that should be prepared in such a way as

to minimize cost of preparation and reproduction.

[Illustration: U. S. GEOLOGICAL SURVEY PREPARATION OF ILLUSTRATIONS

PLATE I

METHODS OF INSERTING PLATES AND FIGURES.

1, 2, 3, 5, 6, 7, plates; 4, 8, 9, 10, figures; 11, pocket.]

The illustrations will be finally divided into plates and figures when

they are fully prepared, but if an author desires to determine the

classification in advance of transmittal he should submit his material

to the section of illustrations, where methods, processes, and

reductions will be decided for each. In determining which shall be

plates and which shall be figures, size and method of reproduction are

the only factors to be considered; there are no other real

differences. Illustrations that require separate or special printing,

such as those reproduced by Lithography and by the photogravure,

photogelatin, and three-color processes, must be printed separately

from the text as plates and inserted in the report at the proper

places; those that are reproduced by relief processes, such as zinc

and copper etching and wax engraving, if not too large, can be printed

with the text as figures. If an illustration to be reproduced by a

relief process is marked for reduction to a size not exceeding that of

the page of the text, it can be called a figure and be printed with

the text. Half tones, though etched in relief, are rarely made text

figures in Survey reports, because to give satisfactory impressions

they must be printed on the best quality of coated paper, which is not

used for the text. By using the coarser screens shown in Plate VI (p.

56), however, a half-tone cut may be made that can be used in the text

if it is smaller than the page.

SIZES OF ILLUSTRATIONS.

The regular book publications of the Geological Survey are issued in

three sizes--(1) octavo (annual reports of the Director, statistical

reports on mineral resources, bulletins, and water-supply papers); (2)

quarto (professional papers and monographs); (3) folio (geologic

folios). The following table gives the measure of the text of each

size and the measure of the trimmed page, in inches:

Size of text. Size of page.

Octavo 4-3/8 by 7-15/16 5-7/8 by 9-1/8

Quarto 6-1/16 by 9-1/8 9-1/4 by 11-5/8

Folio 13-13/16 by 17-7/8 18-1/2 by 21-3/4

Most professional papers are printed in two columns of type, each 3

inches wide, and folios are printed in three columns, each 4-3/8

inches wide. A text figure in one of these publications can be made to

fit one or more columns, and it may run the full length of the text

page.

The limits of the dimensions of plates and figures, in inches, are

given in the following table. If for any reason a plate can not be

reduced to the dimensions of a page it can be folded once or more; and

if it is large and unwieldy it may be placed in a pocket on the inside

of the back cover. (See Pl. I.)

Single-page Plate with

plate. one side fold. Text figure.

Octavo 4-3/8 by 7-1/2 7-1/2 by 8-1/2 4-3/8 by 7-1/2

Quarto 6 by 9 9-1/2 by 14-3/4 3 or 6 by 8-1/2

Folio 15 by 17-1/2 ............ 4-3/8 or 13-13/16 by 17-7/8

For an octavo report a single-page plate with side title should be 4

inches or less in width, and a plate with bottom title should be 7

inches or less in depth. In other words, the actual depth and width

of a single-page plate in a page of any size must depend on the number

of lines in its title, the inclusion of which should not extend the

matter much, if any, beyond the dimensions given in the table. A

difference of 1 inch or less in the width of a folding plate may

determine whether it must be folded once or twice, so that by

consulting this table an author may save expense in binding and

promote the reader's convenience in handling the plate.

A text figure (including the title) can not extend beyond the text

measure but may be of any size or shape within that measure, as shown

on Plate I, figures 4, 8, 9, 10.

SUBDIVISIONS OF PLATES AND FIGURES.

If a plate consists of two or more parts or photographs each part

should be marked with an italic capital letter--=A=, =B=, etc.--which

should be placed directly under each. If it is made up of many parts,

in the form of plates that accompany reports on paleontology, each

part should be similarly marked with an arable numeral--1, 2, 3, etc.

If a text figure is subdivided into two or more parts, each part

should be marked with a roman capital--A, B, C, etc.; and if details

of a part are to be described each detail should be marked by an

italic lower-case letter--a, 6, c, etc.

PREPARATION OF COPY BY AUTHORS.

CHARACTER OF ORIGINAL MATERIAL.

In the Geological Survey, as elsewhere, the "originals"--that is, the

original material submitted by authors for the illustration of their

reports--differ greatly in character and in degree of clearness. Some

are carefully prepared; others are rough, obscure in part, and

defective in detail. Drawings made from poor originals progress

slowly, because the draftsman spends much time in interpreting

uncertain features or in conference with the author concerning

details. An original should be perfectly clear in detail and meaning,

so that the draftsman can follow it without doubt. It should not

consist of parts that must be brought together to make a new drawing,

because the result of the combination of the parts will be uncertain

at the outset and may not prove satisfactory. Each original

illustration should be prepared with the idea that the draftsman who

will make the finished drawing will be unfamiliar with the subject and

will need definite instructions; all data should be plotted and each

figure or plate should be completely made up before it is submitted.

More or less roughly prepared originals are expected, but they should

show no uncertainty in details. Obscure features may be cleared up by

inclosing the features in penciled loops connected by a line with

notes written on the margin, such as "omit this line," "turn at an

angle of 30° from true north," "add," "cut out."

PRELIMINARY PREPARATION OF MAPS.

The base map that generally accompanies a report may be an original

field sheet or it may have been compiled from various sources by an

author and made to incorporate the results of his field work. It

should not be a collection of maps of different scales and standards

to be worked into a new map.

The source of the data shown on every original base map should be

indicated on the map, whether it is to be used as an illustration or

as a record of field work. This information is required as a permanent

record for showing the reliability of the map, for use in comparing

data, and for giving full credit to those who are responsible for the

data. An author should see that this requirement is observed in order

that proper credit may be given and should especially see that all

cooperative agreements and organizations are properly mentioned.

An original map should preferably be complete in itself. It should not

consist of several parts or sheets unless the data to be represented

are unusually complex. All elaborate or technical finish of border

lines, lettering, or like features should be left to the draftsman or

the engraver.

Base maps that involve the compilation of new data should be prepared

by either the topographic branch or the division of Alaskan mineral

resources. If a base map already published is to be reused it should

be submitted to the chief topographic engineer or to the chief of the

division of Alaskan mineral resources for approval. This procedure

will insure a single standard of geographic accuracy in maps appearing

in Survey publications.

A geologist who requires a base map that includes new topographic data

should address a request for its preparation to the chief geologist,

who, through the Director, will refer the request to the topographic

branch. The request must be accompanied by a full statement regarding

the proposed report and the time when it is likely to be submitted.

The preparation of such base maps by draftsmen in the division of

geology, the land-classification board, the water-resources branch, or

the section of illustrations has been discontinued except for the

minor adaptations provided for above.

If a report requires the preparation of a base map that includes no

new topographic data such a map must be compiled from other authentic

maps by the division or branch in which the report originates. If,

however, no draftsmen are available in that division or branch, an

arrangement can be made with any other branch--as the topographic or

publication branch--that may have draftsmen available, with the

understanding that the cost of the work shall be reimbursed to the

branch doing the work by the branch ordering it. For indicating

geologic and other data, however, an author may make use of an

authentic base map already published, and after it is reduced or

enlarged to appropriate scale by photography such a map may suffice

for transmittal with a manuscript.

MATERIAL AVAILABLE FOR BASE MAPS.

The maps already published by the Geological Survey[2] and other

Government bureaus should always be consulted when a new base is to be

compiled. The following list includes most of the maps available:

1. The Survey's regular topographic atlas sheets, published on three

scales--15-minute sheets, scale, 1:62,500; 30-minute sheets, scale,

1:125,000; 60-minute sheets, scale, 1:250,000--approximately 1 mile, 2

miles, and 4 miles to 1 inch, respectively--and its "special" maps,[2]

some of which are published on other scales. All these maps can be

used as bases for detailed geologic maps, for compiling maps on

smaller scales, and for revising other maps.

2. The United States part of the international map of the world, now

being published on the scale of 1:1,000,000 (approximately 16 miles to

1 inch). Each sheet of this map represents an area measuring 6° of

longitude and 4° of latitude. The published sheets of this map may be

used as bases for general maps. The sheets are drawn on the scale of

1:500,000, and photolithographs on this scale are available for use as

bases for geologic or other maps.

The adaptability of the 1:1,000,000 scale map to use as a base for

general geologic maps is shown in the geologic maps of the southern

peninsula of Michigan and of Indiana in Monograph 53 (Pls. IV and

VII), the map of Florida in Bulletin 60 (Pl. I), and the map of

Vermont in Water-Supply Paper 424 (Pl. I).

3. The Survey's two-sheet wall map of the United States, 49 by 76

inches, scale 1:2,500,000 (approximately 40 miles to 1 inch). Parts of

this map can be used as bases for general geologic or other maps and

as copy for index and other small diagrammatic maps. This map is

published both with and without contours.

4. Land Office maps and township plats. These maps are now being

published on a scale of 12 miles to 1 inch; they are also

photo-lithographed on one-half that scale, or 24 miles to 1 inch. The

township plats are printed on a scale of one-half mile to 1 inch. The

maps are especially useful in compiling maps in which land lines

(townships and sections) are essential, and the township plats afford

valuable detail and are useful in field work and in revising other

maps. Township and section lines should appear on all

land-classification maps published by the Survey. On maps on a scale

less than 1:250,000 only the townships should be shown; on maps on

scales greater than 1:250,000 the sections should be shown; on maps on

a scale of 1:250,000 the sections should be shown, unless their

representation will materially impair the legibility of the map, in

which case only the townships should be shown. (See fig. 1.)

5. Post-route maps, covering single States or groups of adjacent

States, published on sheets of different sizes and on scales

determined mainly by the size of the State. The map of Texas is

published on a scale of 12 miles to 1 inch, that of Virginia on a

scale of 7 miles to 1 inch, and that of West Virginia on a scale of 6

miles to 1 inch. Both the Land Office and the post-route maps are

useful for reference in compiling maps on smaller scales. Post-route

maps are especially useful for comparing and verifying the location of

cities, towns, and railroads.

6. Coast and Geodetic Survey charts, published on scales that are

governed by the area represented and the amount of detail to be shown.

These maps should always be used in compiling and correcting coast

lines.

7. Maps and charts published by the Corps of Engineers of the Army,

the Mississippi River Commission, the surveys of the Great Lakes, and

the boundary surveys. These maps are especially useful if the scale of

the map to be compiled requires considerable detail.

8. The Survey's three small base maps of the United States--(_a_) a

map 18 by 28 inches, scale 110 miles to 1 inch, which is published

both with and without contours, or with relief or hypsometric shading;

(_b_) a map 11 by 16 inches, scale 190 miles to 1 inch; (_c_) a map

7-1/2 by 12 inches, scale 260 miles to 1 inch, designed for use as a

two-page illustration in a bulletin or a water-supply paper.

9. The Century, Rand McNally & Co.'s, Cram's, Stieler's, The Times,

Johnston's Royal, and county atlases.

10. State and county maps.

11. Railroad surveys, which are useful in furnishing data for

elevations as well as for locations of towns and stations.

12. The latest national-forest maps and proclamations. It is, however,

not necessary that national forests, bird reservations, and national

monuments be shown on a map in a report unless their addition is

specially requested by the author or by the chief of the branch

submitting the report, and they should not be shown if they will

obscure other more important data.

[Footnote 2: See "Topographic maps and folios and geologic folios

published by the United States Geological Survey" (latest edition).]

[Illustration: Figure 1.--Diagrams showing principal, guide, and

auxiliary meridians, standard and special parallels and correction

lines, and system of numbering townships, ranges, and sections.]

The Survey has published numerous maps of parts of Alaska, as well as

other maps, which are available for use or reuse in its reports.

Copies of all base maps for which copper plates have been engraved by

the Survey can be obtained on requisition, and their use in a new

report will save time as well as the cost of engraving. Other maps

will be found in the Survey library, where the latest editions only

should be consulted.

BASIC FEATURES OF MAPS.

It must be remembered that "every map, whatever its scale, is a

reduction from nature and consequently must be more or less

generalized."[3] The degree of generalization in the geologic and

other detail to be shown on a map usually involves a corresponding

degree of generalization in its base. Absolutely true generalization

means the same degree of omission of detail for each kind of feature.

If a base map on a scale of 1 mile to 1 inch, prepared with the usual

detail, were placed before a camera and reduced to a scale of 16 miles

to 1 inch, the lines representing the smaller tributaries of streams

and the smaller water bodies, as well as many other features, would

probably be so greatly reduced in length as to be illegible. If from

this reduced photograph a new map were prepared, from which all

features not plainly discernible were omitted, the new map should

represent what might be called true generalization. This degree of

generalization is, however, not practicable, but unessential detail

should be systematically omitted. The amount of detail which a base

map should show is limited by its scale, by the character of the

country it represents, and by the kind of data to be shown. Coordinate

features of a topographic map should be shown with equal detail.

Detail in culture may call for detail in drainage, though relief may

be greatly generalized or entirely omitted; detail in relief may

like-wise call for detail in drainage, though culture may be more

generalized.

[Footnote 3: Gannett, Henry, A manual of topographic methods: U. S.

Geol. Survey Mon. 22, p. 107, 1893.]

If the three fundamental features of a topographic map--the culture,

the drainage, and the relief--are to be engraved or photo-lithographed

separately and printed in colors, the best results can be obtained by

drawing each feature in a separate color on one sheet unless the work

is coarse and great precision in register is not needed. The culture

should be drawn in black waterproof ink, the drainage in Prussian

blue, and the relief in burnt sienna; but care should be taken that

the colors used will photograph well. To insure a good photograph it

is usually necessary to add a little black to the blue and brown. (See

"Inks," p. 25.) The photographer will then make three negatives and

will opaque or paint out all but one of the three features on each

negative. The cost is somewhat greater than that of reproducing three

separate drawings, but the result gives more accurate register than if

the drawings were made on separate sheets, which are likely to change

in size before they are reproduced.

STANDARD SCALES.

The standard scales of the maps used in the publications of the

Geological Survey are fractions or multiples of 1:1,000,000 (see p.

14), except for a map that is reduced expressly to fit one or two

pages of a report or that is reduced horizontally or vertically to fit

the text as a small diagrammatic or index map. It should be remembered

that a map which may be serviceable for use in compiling a new map,

except as to scale, can be reduced or enlarged to the scale of the new

drawing by photography, by a pantograph, or by other means. (See p.

47.)

Maps compiled by an author should be prepared on a scale of at least

1-1/2 times and preferably twice the size of the scale used on the

published map. Maps traced on linen should be no less than twice the

size of publication. Not only is the quality of the reproduction

improved by considerable reduction, but the larger scale of the

drawing facilitates the plotting of details. It should be remembered,

however, that a linear reduction of one-half produces a map only

one-fourth the area of the original, and reduction so great may

prevent the addition of data, such as an extended note in small

letters applying to a small area on the face of a map, which would not

be legible when reduced.

ORIENTATION OF MAPS.

A map that bears no arrow indicating north is supposed to be oriented

north and south, and its title should read from west to east. If,

however, the area mapped has a general trend in one direction, as

northwest to southeast, and its squaring up by a north-south line

would leave too much blank paper, this general rule is not followed.

The border lines on such a map should conform to the general trend of

the area mapped, an arrow should show north, and the title and scale

should be placed horizontally, but the projection numbers and town

names should follow the direction of the parallels of latitude. (See

Pis. X and XII, Bull. 628; and Pis. VI, XV, and XVI, Mon. 52.)

PROJECTION.[4]

[Footnote 4: See also pp. 43-45, where the method of projecting a map

is more fully explained.]

The polyconic projection has been adopted by the Geological Survey for

its topographic atlas sheets and must be consistently used for its

other maps. If a new map is to be compiled an accurate projection

should first be constructed, and no plotting should be done on it

until the projection has been checked and found to be correct. A

projection should be checked or proved by some one other than the

person who prepared it. Next the drainage and the water areas should

be outlined; then the cultural features should be added; and finally

the relief, whether expressed by contour lines, hachures, or

shading.[5]

[Footnote 5: See pp. 49-48 for methods of tracing and transferring.]

EXPLANATION.

Under the heading "Explanation" should be placed all matter needed to

describe fully the details of an illustration, whether map, diagram,

or section, so that if the illustration became detached it would be a

complete self-explanatory unit.

The explanation of a map may be placed inside the border lines if

there is ample room for it, or it may be placed outside. The standard

arrangement for an outside explanation for geologic maps is shown, in

the geologic folios, which should be followed in general form. If

there is space within the border lines the explanation may be

appropriately arranged therein, either in a vertical column or

horizontally, according to the size and shape of the space available.

If the sequence of formation is shown by horizontal arrangement the

younger formations are placed at the left and the older at the right.

If it is shown by a vertical arrangement the youngest formation is

placed at the top.

Each original map submitted by an author should have at least 4-1/2

inches of blank margin on the right and at the bottom in which to

place the explanation, scale, title, and other matter, but the author

should make no attempt to elaborate these features nor should he

employ a draftsman to letter them carefully. Plainly written ordinary

script is quits sufficient for original maps; the final lettering,

which may consist entirely of impressions from type, will be added

after submittal of a report.

TITLES OF MAPS AND OTHER ILLUSTRATIONS.

The titles of maps should be supplied by authors but are subject to

revision in order to make them agree with established forms. They

should be written in ordinary script, not carefully lettered. They

should state concisely the kind of map, the area shown, the special

features represented, and the county, State, or Territory in which the

area is located. (See p. 58.) Titles are reproduced directly only on

lithographs, three-color prints, photogelatin plates, and other

illustrations that are printed by contractors, not by the Government

Printing Office. The titles of illustrations that are reproduced by

relief processes, such as zinc etching, half tone, and wax engraving,

are printed at the Government Printing Office from type, and proofs

are submitted to the authors for examination.

SYMBOLS USED ON MAPS.

GENERAL FEATURES.

More than 200 symbols have been used on maps to express 25 different

kinds of data, a fact indicating at once a notable lack of uniformity

and a need of standardization. It is of course impossible to provide a

characteristic symbol that can be used uniformly for each kind of

feature, and therefore the same symbol may be used on different maps

to express different things. The symbols shown in Plate II are those

most used on geologic maps. The symbols for dip and strike, fault

lines, mine shafts, prospects, and several others are generally well

known, but on some maps it may be necessary to modify a standard

symbol to express additional distinctions. The symbols shown, however,

will cover all the ordinary requirements of miscellaneous mapping.

Though the plate shows more than one symbol for some features the

symbol most commonly used is given first and should be preferred. The

center of each symbol should mark the location of the feature

symbolized. Symbols are not always platted with sufficient care. On

small-scale maps they are difficult to locate and unless great care is

taken in platting them they are likely to be several miles out of

place. All symbols should be located precisely where they belong.

The symbol showing dip and strike should be accurately platted by

means of a protractor, so that the strike will be shown graphically,

without a number and a degree mark, and not need replatting by a

draftsman or engraver. The dip, however, should be indicated by a

number and a degree mark.

LETTER SYMBOLS.

The letter symbols used on most geologic maps to indicate the ages

and names of the formations represented consist of two or more

letters--an initial capital letter for the name of the system and

one or more lower-case letters for the name of the formation or of

the material, as Qt (Quaternary--lower terrace deposits); Cpv

(Carboniferous--Pottsville formation); COk (Cambrian-Ordovician--Knox

dolomite), etc. The standard usage for this feature is shown in the

geologic folios but is subject to modification in other publications.

In preparing an original geologic map a letter symbol, such as has

been just described, or a number should be put in the proper place in

the explanation, and the same symbol or number should be repeated at

one or more places on the map within the areas to which it refers.

Each area that is indicated by a color should be marked with the

proper symbol in order to make its identification sure, for light

colors especially are likely to fade and mixed colors can not be

discriminated with certainty.

[Illustration: U. S. GEOLOGICAL SURVEY

PREPARATION OF ILLUSTRATIONS PLATE II

SYMBOLS USED ON GEOLOGIC MAPS, ECONOMIC MAPS AND MINE PLANS]

OIL AND GAS SYMBOLS.

A complete set of symbols for maps showing oil and gas is given on

Plate II. Referring to these symbols the chief geologist, in a

memorandum to the Director, writes:

The symbols used by the Survey in its oil and gas maps have

not been in accord with those used by the oil companies, nor

have they been wholly logical. It appears that though they

were submitted for recommendation they never have been

formally approved.

Herewith I submit a code prepared by the geologists of the

oil and gas section. They conform largely to commercial use

and embrace its best features as well as the best and most

logical features of our previous usage, the departures from

which are, after all, of minor consequence.

The symbols here submitted [see PI. II] with recommendation

for approval are founded on a building-up system, so that the

history and the results of drilling at any location can be

recorded by slight additions to symbol and without erasure.

Thus maps may be revised without scratching.

In drawing these symbols the draftsman should make the rays

of the gas well distinct and in adding the vertical bar or

line showing that a hole is dry or abandoned should make it

long enough to be distinct. It would be preferable to draw

this bar obliquely, but an oblique position would coincide

with some of the patterns on certain maps, and it should

therefore be placed vertically. The vertical line indicates

the failure or abandonment of the well, the symbol for which

Is thus scratched off or canceled by the line drawn through

it. The symbols agree so far with commercial usage that oil

men will have little need to consult the explanation.

SYMBOLS FOR USE ON MAPS SHOWING FEATURES OF GROUND WATER.

The symbols used on maps relating to ground water represent the

features named below, each of which has been shown in publications

already issued.

Area of absorption or outcrop. Area that discharges ground water.

Depth to water table. Quality of ground water.

Contours of water table. Area irrigated with ground water.

Fluctuation of water table. Nonflowing well.

Depth to water-bearing formation. Flowing well.

Structure contours of water-bearing Unsuccessful or dry well,

formation. Well with pumping plant.

Area of artesian flow. Spring.

Head of artesian water.

The lack of uniformity in the symbols commonly employed to represent

these features is due to differences in the number of color on the

maps and differences in the scale. Standard colors for the larger

features, such as those for areas of artesian flow, areas of

absorption, and curves showing depths to water table or to

water-bearing formations, can not be fixed, because of considerations

of economy in printing. For example, if light green is the standard

color to be used for delineating areas irrigated by ground water and

no green is used on other parts of the map its use would represent an

additional or special printing, whereas a tint of blue, brown, or

purple, if any of these colors is used for other features on the map,

might be used also for this feature without additional printing.

Therefore the general use of any particular color for a water feature

seems to be impracticable; but this fact should not preclude the

adoption of color standards for use subject to the requirements of

economy in publication.

The ordinary symbols for wells are the open circle and the solid

circle, or dot. Only in the secondary or specific well symbols does

there appear to be lack of uniformity, the choice of secondary symbols

being governed either by personal preference or by the requirements

for specific distinction.

All symbols should, if possible, suggest the things they represent.

Wells are circular and hence the open circle is most used and most

appropriate for nonflowing wells. To indicate a flowing well the

circle is made solid, denoting that the well is full of water. For an

unsuccessful well the most suggestive symbol would be an open circle

with a line drawn through it to denote cancellation. It has been

suggested that if water features, including wells, are to be printed

in blue, unsuccessful wells, or dry holes, be printed in black. A

large circle drawn around the symbol for a flowing or nonflowing well

will appropriately denote a pumping plant at the well.

The accepted symbol for a spring is a dot with a waved tail

representing the direction of flow, if known. This symbol can not be

modified without destroying its prime characteristics, but it may be

accompanied by a letter indicating the kind of spring. An open circle

with a tail might be used on large-scale maps, but it would be out of

scale on other maps, whereas the black or blue dot and tail will fit

maps of any scale.

The following colors and symbols can most appropriately be used to

represent ground-water features. The well and spring symbols can be

varied by adding letters if they are necessary to express other data

than those indicated in the list below.

_General ground-water features._

Area of absorption or outcrop: Flat color used on the map to

show the geologic system in which the absorbing formation

occurs.

Areas showing depths to water table: Shades of purple and gray;

if possible the shades showing the areas of least depth

should be darkest and the shades should grade from those to

lighter tints.

Contours of water table, or contours on water-bearing

formations: Gray or purple curves or lines.

Areas of artesian flow: Blue flat tint, or fine ruling in blue.

Depth to water-bearing formations: Gradation of a single

color or of two related colors from dark for shallow depths

to light for greater depths.

Nonflowing artesian areas (pumped wells): Green flat tint, or

fine ruling in green. Depth to water-bearing formations shown

by gradation of tint if possible from dark for shallow depths

to light for greater depths.

Head of artesian water: Blue curves or lines.

Areas that discharge ground water: Blue flat tint, or fine

ruling in blue.

Areas irrigated with ground water: Green flat tint, or fine

ruling in green.

[Illustration] Well, character not indicated. [Illustration]

Well, nonflowing. [Illustration] Well, flowing.

[Illustration] Well, unsuccessful or dry. [Illustration]

Well, nonflowing, with pumping plant [Illustration] Well,

flowing, with pumping plant. [Illustration] Springs.

[Illustration] Spring, thermal. [Illustration] Spring,

mineral.

The standard color scheme should be used if no conditions preclude its

use, but if other colors can be used with greater economy without

sacrificing clearness the use of the standard colors should be waived.

BLACK-LINE CONVENTIONS.

A complete set of the black-line patterns used to distinguish areas on

a map is given in Plate VIII (p. 60), and their application to a

finished drawing is shown in figure 9 (p. 62). These patterns,

however, should preferably not be used by the author in his

preliminary work on an illustration. For this purpose water colors or

colored crayons are preferable, and the distinctions between areas may

be emphasized by letter symbols.

MATERIALS USED IN PREPARING MAPS.

PAPER.

For large and important maps which may at some time be extended to

cover a greater area or which may be made to fit maps already prepared

or published the paper used should be mounted on muslin to reduce to a

minimum the shrinking or stretching caused by atmospheric changes.

Pure white paper produces a better negative than a cream or yellowish

paper and will retain its color longer, but all papers become more

yellow with age and exposure to light.

The following brands of paper are used in the Survey in the

preparation of maps:

"Normal" K. & E., unmounted. Has an excellent surface and comes in

flat sheets, 19 by 24, 22 by 30, and 27 by 40 inches.

"Paragon" K. & E., mounted on muslin. In 10-yard rolls 72 inches wide.

Used in the Survey for large office drawings and maps of large scale.

"Anvil" K. & E., mounted on muslin. In 10-yard rolls 42, 62, and 72

inches wide. Used in the Survey for large drawings.

"Whatman's hot pressed," unmounted or mounted on muslin. In sheets

ranging in size from 13 by 17 to 31 by 53 inches. An excellent paper

for maps. The muslin-backed paper is recommended for use in preparing

large detailed maps and base maps that are to be retained as permanent

records. The muslin provides a durable and flexible backing that

permits the map to be rolled, and paper thus mounted is particularly

serviceable for a map which may be subjected to considerable revision

and to which must be added finally a title, explanation, and other

marginal matter.

"Ross's relief hand-stipple drawing paper." A stiff enameled or

chalk-coated paper whose surface has been compressed into minute

points that stand in slight relief so that a shade made on it with

pencil or crayon is broken up into dots and can be reproduced by

photo-engraving. For use in making shaded drawings, drawings showing

relief by light and shade, etc. Similar paper is prepared for

parallel-line and other pattern effects. In sheets ranging in size

from 11 by 14 to 22 by 28 inches. (See p. 51 for method of using.)

Profile and cross-section paper. In sheets of convenient sizes or in

rolls. Bears lines printed in blue, green, red, or orange, in many

kinds of rulings, which may be selected by reference to catalogues.

Profile and cross-section paper printed in orange is recommended for

preliminary drawings; blue is recommended for drawings that are made

in pencil and submitted for inking in.

BRISTOL BOARD.

For the smaller maps, such as key maps and maps less than 18 by 24

inches, and for small drawings made for direct reproduction,

Reynolds's bristol board is recommended on account of its pure-white

color and its hardness, which permits erasures to be made without

affecting redrawing over the corrected area. It is obtained in 2-ply,

3-ply, and 4-ply sheets. The 2-ply and 3-ply are especially useful in

making delicate brush and pencil drawings and pen and ink drawings.

The sizes used in the Survey are 16-1/2 by 20-3/4, 18-1/4 by 22-3/8,

and 21-1/2 by 28-3/4 inches.

TRACING LINEN.

Tracing cloth or linen is especially useful for large work that will

require considerable reduction. (See p. 18.) Its advantages are that a

tracing that has been carefully made on it over any kind of copy for

direct reproduction by a photo-engraving process can be used for

making a paper negative for contact printing or blue printing. On the

other hand, it is susceptible to atmospheric changes that affect

scale, and the lines traced on it are not reproduced as sharply as

those made on paper. It can be obtained in rolls 30 to 54 inches wide.

Erasures should be made on tracing linen with a hard rubber eraser,

not with a sand rubber or a steel eraser.

INKS.

The best drawing inks are in liquid form, ready for use. They should

be waterproof and equal to the grade known as Higgins's waterproof

ink. When a suitable waterproof blue ink can not be obtained, a good

blue for features of drainage can be made by dissolving a half pan of

Winsor & Newton's prussian blue in water. No good waterproof burnt

sienna ink seems to be obtainable, but a good substitute can be made

by dissolving Winsor & Newton's water color of that name.

Ink lines should be drawn in full strength of color--lines that should

be black must not appear grayish, for example--and pens should be kept

clean. The same pen should not be used for applying two inks, as the

mixture thus produced is likely to thicken or coagulate on the pen. A

little black should be added to colored inks that are used in making

drawings to be reproduced in colors in order to strengthen the lines

for photographic reproduction.

DRAWING PENS.

The pens made by Keuffel & Esser, especially their No. 3202, and

Gillott's Nos. 291, 290, 170, and 303 give complete satisfaction. The

Gillott numbers are given in the order of fineness of the points. No.

291 being the finest. The best cleaner for a drawing pen is a piece of

chamois skin.

PENCILS.

Pencils used for drawing should have leads of a quality equal to those

of the Koh-i-noor brand, in which the grades of hardness are indicated

by 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, and 9H; the

softest grade is 3B and the hardest 9H. The grades most generally used

are B, HB, F, 4H, and 6H.

RUBBER ERASERS AND CLEANERS.

Two kinds of rubber erasers are usually employed in making erasures on

drawings--a hard, dense rubber like the "Ruby," and a soft, pliable

rubber like the "Venus" or "H" (Hardtmuth). The soft rubber is also

useful for cleaning large surfaces. Art gum is also recommended for

this purpose and has the advantage of not disturbing the surface of

the paper.

COLORED PENCILS AND CRAYONS.

Colored pencils and crayons are useful only for coloring preliminary

maps. They are not recommended for use on maps that are to be kept for

reference or to be submitted for reproduction, because the colors rub

off, but they can be used on photographic prints of base maps or on

transparent oversheets, for which the unglazed side of tracing cloth

is well suited. When they are so used register marks should be added

at numerous points on the map and the oversheet, including the four

comers, the color boundaries should be drawn or traced, and finally

the colors should be added. Two or more colors should not be used on

any one area to modify a tone, but each area should be colored with a

separate crayon. Patterns or designs should not be used except to

strengthen contrasts, and for that purpose a pattern may be drawn with

a black pencil over a color.

WATER COLORS.

By dilution to half strength some of the standard water colors will

yield a tint or hue that will contrast with other tints or hues

produced in the same way quits as well as undiluted or full colors

will contrast with one another. The colors named below, except

chrome-yellow and emerald-green, are among those that when diluted

will afford satisfactory contrasts among themselves and with their

full colors and are recommended for use in coloring original maps.

Mauve. Hooker's green No. 2.

Crimson lake. Emerald-green.

Orange-vermilion. Payne's gray.

Burnt sienna. Lampblack.

Cadmium-yellow. Sepia.

Chrome-yellow. Cerulean blue.

Olive-green.

Other pigments spread better than cerulean blue and emerald-green, but

the exceptional purity of color of these two seems to warrant their

use.

JAPANESE TRANSPARENT WATER COLORS.

Japanese transparent water colors, so called, are used by some

geologists. They spread evenly and are convenient for field use, but

they can not be washed out like other water colors, so that when they

are once applied to an area and a change of color becomes necessary

they must be bleached out. A good bleach is sodium hypochlorite, which

should be applied with a brush until the color disappears, and the

area dried with a blotter before recoloring. Light tints of these

colors are believed to be somewhat fugitive if exposed to strong

light.

COLORING GEOLOGIC MAPS.

The colors used on most original maps are not pleasing, a fact that is

of no particular importance, but--and this is of importance--they

often fail to give clear distinctions; the separate areas can not

always be identified or distinguished with certainty. Again, some

colors are fugitive, and when laid on in light tints they disappear

entirely or become uncertain. Much of the difficulty in identifying

and discriminating colors on an author's original maps is due to the

promiscuous mixing of colors. Many persons can not match or

discriminate mixed or broken colors. Hence if the supply of a color

produced by mixing becomes exhausted and the attempt is made to

duplicate it by a second mixture the two will probably fail to match.

It is therefore suggested that colors in full strength and colors

diluted to half strength be used instead of mixtures of two or more

pigments, so that one color in two strengths or tones can be employed

to indicate areas that are to be distinguished. The colors listed on

page 26 will give 24 satisfactory distinctions and will thus supply

all demands for map coloring.

To insure satisfactory contrasts between colored areas on a map,

unlike colors should be placed next to each other--that is, colors

should be placed together that are widely separated in the spectrum,

such as yellow and mauve, red and green, blue and orange, burnt sienna

and olive-green; not such as red and orange, blue and purple, orange

and yellow, sepia and burnt sienna.

A sufficient quantity of water and color pigment to be used for one

formation area on a map should be stirred in a saucer until the

desired tint is produced before it is applied. To maintain the same

tone properly the color should be well stirred every time the brush is

filled; if it is not stirred the brush will on the next dipping take

up a lighter tint, because most pigments, especially those derived

from minerals, tend to precipitate. When the colors are applied the

map should preferably be placed in a slightly inclined position, and

the coloring should be started at the upper boundaries of an area to

be colored, the well-filled brush being pulled toward the painter and

Worked rapidly back and forth horizontally, the edges of the fresh

color being kept wet. If the edges are allowed to dry, a hard line and

a smeared or uneven effect will be produced.

A strong color should generally be used for small areas unless the map

shows also large areas that must have the same color; lighter hues

should be used for large areas. Bright colors are best suited for

areas of igneous rocks, dikes, and veins, and these may be reduced in

strength for the larger areas.

The Survey's color scheme (see p. 63) need not be applied at this

stage of preparation, except in the most general way. Appropriate

final colors can be best selected when the new map is made ready for

engraving. In the author's original maps adequate color distinctions

between areas are more important than the use of standard geologic

colors. Patterns should not be ruled in one color on an original map

to indicate distinctions between different formations of the same age

or period, because such patterns are difficult to produce by hand with

proper uniformity except by engraving.

It is of vital importance that an original base map should be free

from colors and from technical symbols in order that it may be kept

clean for photographing and preserved for possible future use. Such a

map should preferably be photographed in order to obtain prints on

which to add the colors and symbols; the use of an oversheet for this

purpose is not nearly so satisfactory. When photographed a base map

should be reduced to publication scale in order to save the additional

cost of a larger negative, and this reduced map may be made up for

publication by the addition of colors and symbols, title, explanation,

etc.; but the lithographer will also need the original base map from

which to make his reproduction.

DIAGRAMS.

ESSENTIAL FEATURES.

The term "diagrams," as used here, includes such illustrations as mine

plans, profiles, sections, stereograms, and maps that are more

diagrammatic than cartographic. The first essential in the original

drawings for simple diagrams is clearness of copy. Simplicity of

subject does not warrant hasty preparation, for an original sketch

that has been carelessly drawn and is inaccurate or inconsistent in

detail may lead to serious errors. Ruled paper printed especially for

platting profiles and cross sections should be used. Curves or graphs

made by an author with pencil on blue-lined section paper may be inked

by more skillful draftsmen. An author's pencil sketches are usually

satisfactory if they indicate plainly the facts to be represented, but

they should be prepared with some care as to detail. Tables and like

matter are not generally satisfactory material from which to prepare

drawings. In drawings for diagrams that are to be printed in the text

as figures the use of large, solid black bars or of conspicuous areas

of solid black is objectionable, because the black is likely to print

gray and to appear uneven in tone. Ruled tints or cross lining give

better effects. Stereograms should be prepared by an author with

especial care, for they represent facts only as the author sees them,

and the author's view must be imparted to the draftsman graphically.

The "third dimension"--the relief--in such drawings is not easily

expressed and should be brought out clearly in the author's rough

sketches.

For illustrations of apparatus photographs are preferred, but if rough

sketches are submitted they should show not only correct relations but

all dimensions.

PLANS OF MINE WORKINGS.

Blue prints obtained from mining companies are acceptable for plans of

mines or underground workings, but all unnecessary or irrelevant

details on such plans must be canceled and all essential features

retained, and every essential feature, especially any added data, must

be clearly interpretable. Many such blue prints are so large and

unwieldy that they must be greatly reduced by photography before they

can be redrawn. If the lines are too weak to photograph, a tracing of

the essential parts can be made and reduced to about twice publication

size. The shadowless drafting table, described on pages 47-48, is well

adapted to the work of making such tracings. Blue prints can also be

pantographed to any convenient size if the details are not too minute

or complex.

[Illustration: Figure 2.--Conventional lines used in preparing plans

and diagrams of mine workings to distinguish different levels.]

The levels in plans of underground workings can be differentiated in

finished drawings by a system of conventional outlines in black, as

shown in figure 2, by conventional patterns or symbols within plain

outlines, or by colors. Such plans should not be printed in colors

unless the maze of workings is so complex that lines showing the

different levels would become confused or obscure if printed in black.

SECTIONS.

The standard forms of geologic sections are shown in the geologic

folios. Structure sections should be prepared with great care as to

detail but without attempt at refinement of lines and lettering. The

author's drawing of a section along a line or zone that is not

definitely indicated by a line on an accompanying map should be so

prepared that it may be copied exactly. On the other hand, the

draftsman, in reproducing a section that represents the structure

along a given line or zone, may be able to make the outcrops coincide

with the topography and the formation boundaries shown on the map, but

the structure, or the interpretation of it to be given, should be

carefully worked out by the author. All essential facts relating to

bedding, folding, faulting, crosscutting dikes and veins, or other

significant details should be indicated with precision. No attempt

need be made to draw firm, steady lines so long as the essential facts

are clearly expressed.

All sections should be drawn to scale, and both the vertical and the

horizontal scale should be given on the drawing. These scales should

be uniform if possible, or at least the vertical exaggeration should

be minimized. Too great vertical exaggeration creates distortion and

is grossly misleading. Sections should be drawn to scale on ruled

paper prepared for the use of authors. Such paper may be obtained on

requisition.

[Illustration: Figure 3.--Section and perspective view showing

relations of surface features to the different kinds of rock and the

structure of the beds.]

A kind of cross section which is not often used but which gives a

more pictorial and clearer conception of underground relations than

other kinds is made by adding a sketch of the topography above the

section. This sketch should be a perspective view, in which the

prominent features shown hypothetically in the section below it will

be reflected in the topography. Such a sketch might show, for example,

not only monoclinal slopes, "hogbacks" due to steeply upturned beds,

terraces, escarpments, and like features, but volcanic necks or other

extruded masses in their true relations to the underground geology of

the country. (See fig, 3.) In submitting the draft of such an

illustration the author should, if possible, submit also a sketch or

photographs of the adjacent country and indicate on the section the

point of view by notes such as "Sketch A made at this point," "See

photograph B." The sketch will be more useful if it is prepared on a

scale consistent with the details of the section. It may be made with

a pencil and should show as well as possible the relations of the

features in the landscape to those in the section. Some good examples

of illustrations of this type can be found in Powell's "Exploration of

the Colorado River," pages 182-193. One simpler figure of the same

kind is given on the cover of the geologic folios.

In preparing original drawings representing columnar sections, or

sections in wells or ravines, the author should indicate all

well-defined or important local features of structure, such as

cross-bedding, ore bodies, or lenses. If there are no unusual features

or details, the subdivisions need be identified only by names of

materials, such as "thin-bedded limestone," or "slates with some

coal," the coal beds being shown. The sections should, however, be so

plotted and subdivided by the author that each section or group of

sections will be complete in its crude form. The compilation of

various parts into one unit and the construction of columnar sections

by reference to tables alone is an essential part of the author's

original preparation.

[Illustration: Figure 4.--Sections of coal beds. The Figure shows the

publications size and the arrangement at the sections. Each section

should be drawn three-tenths or four-tenths of an inch wide and

reduced one-half. Thicknesses can be indicated by numbers, as shown on

sections 1 and 10, or by bar scale.]

Sections designed to show the relative thickness of beds of coal,

arranged in groups for publication either as plates or figures, should

be drawn in columns three or four tenths of an inch wide and reduced

one-half, as shown in figure 4. These sections, whether correlated or

not, should be drawn to some definite vertical scale and should show

the thickness of the coal beds, preferably by numbers indicating feet

and inches, the other material being symbolized and the symbols

explained graphically, as shown in figure 4. The vertical scale should

always be stated for the use of the draftsman. A bar scale may be

used instead of figures showing the dimensions of the individual beds.

LITHOLOGIC SYMBOLS.

The symbols used to indicate the various kinds of rocks illustrated in

sections and diagrams are shown in Plate III. The units or elements of

these symbols may be spaced more openly in generalized diagrammatic

sections than in sections that show great detail.

Symbols should be used consistently throughout a report, and in order

to make them consistent a set showing the symbol to be used for each

kind of rock to be indicated should be prepared before the original

drawings are made. Some inconsistencies may be unavoidable on account

of the small size of some areas shown and the contrast needed between

others; but the deviations from the set of symbols adopted should be

minimized.

USE OF PHOTOGRAPHS AS ILLUSTRATIONS.

ESSENTIAL FEATURES.

The foundation of a good photographic print is a good negative, and

the best prints for reproduction as illustrations are those made from

negatives in which the illumination is evenly distributed and the

details are sharp--such negatives as are obtainable only by the use of

small stops and correct focusing. A good print should not present too

sharp contrasts between its dark and its light parts; if it does, the

printed reproduction will show a loss of detail in both. Sufficiency

of detail depends largely on focus, stopping down, and timing;

brilliancy is the direct result of ample illumination by sun or

artificial light, without which a photograph will be dull or "flat"

and generally unsatisfactory for reproduction. Bad weather may prevent

good field exposures, yet even in bad weather acceptable negatives may

be obtained by judicious focusing, stopping down, and timing. If a

negative is overexposed it may be full of detail, but flat and too

thin to print well. If underexposed it will show no details in its

lighter parts and the shadows will be black; and a black shadow is

nothing less than a blemish. Some detail should appear in all shadows

and in the middle tones, and some should appear in the high lights;

and a print in which these are evenly developed and in which the

illumination is distributed uniformly is technically perfect.

Unfortunately not all field photographs are good, so an author must

select from his collection those which will make the best half tones.

In making this selection he should of course consider, first, the

scientific value of the photograph, and next, its pictorial or

artistic quality, which, though of secondary importance, should

nevertheless be kept in mind. A feature worthy of illustration

deserves good pictorial expression; if it is of superior scientific

interest it should not be represented by an inferior photograph.

Fortunately, a good, accurate drawing may be made from a poor

photograph, and a photographic view that has only minor defects can be

successfully retouched. Photographs that need much retouching should

generally be larger than publication size, for the effects of

retouching--brush marks, etc.--will be softened by reduction.

Photographs that need only slight retouching need not be larger than

publication size. A photograph can rarely be satisfactorily enlarged

in reproduction unless it is sharp in detail and requires no

retouching.

[Illustration: U. S. GEOLOGICAL SURVEY

PREPARATION OF ILLUSTRATIONS. PLATE III.

LITHOLOGIC SYMBOLS USED IN STRUCTURE AND COLUMNAR SECTIONS TO

REPRESENT DIFFERENT KINDS OF ROCK]

Unmounted prints are always preferable for use in making

illustrations. A group that is to form a single plate should be placed

in an envelope bearing the number of the plate and its title, and each

print of the group should bear a corresponding number, written in

pencil on its back. The envelope will protect the prints and keep them

together, and the numbers will identify them. Red ink should not be

used to mark photographs, as it is likely to penetrate the coating or

even the fiber of the paper, so that it can not be erased.

If a print is of doubtful quality two copies of it should be

submitted--one glazed, the other having a dead finish or "mat"

surface, which is generally preferable if the print must be

considerably retouched. The best prints for use as illustrations are

those made on "regular" or "special" semimat velox and glossy haloid

papers. The author should indicate prints that may be grouped together

according to their relation geographically or by subject. Generally

two half tones will be combined on a page, and the list of

illustrations should be prepared accordingly.

With slight trimming and reduction, three photographs measuring 3-1/4

by 5-1/2 inches may be made up one above the other to form a full-page

octavo plate. Four photographs in which the longer dimensions

represent vertical distances may sometimes be used if they are placed

sidewise on the page, with side titles.

Some photographs may be reduced to the width of a page by trimming

instead of by photographic reduction, which may involve loss of

detail. The author should clearly indicate the extent of such trimming

as they may bear without loss of essential details. The trimming is

best done during the final preparation. A line should not be drawn

across a photograph to mark such trimming, but the position of the

line or lines should be indicated either on temporary mounts, on the

backs of the prints, or by a statement, such as "One inch may be cut

off on right, one-fourth inch on left, and one-half inch at bottom."

COPYRIGHTED PHOTOGRAPHS.

Section 4965 (ch. 3, title 60) of the Revised Statutes, amended by act

of March 2, 1895 (Stat. L., vol. 28, p. 965), provides that no

copyrighted photograph may be used without the consent of the

proprietor of the copyright in writing signed in the presence of two

witnesses. A penalty of $1 is imposed for every sheet on which such a

photograph is reproduced without consents, "either printing, printed,

copied, published, imported, or exposed for sale." An author should

therefore obtain the written consent of the owner of a copyrighted

photograph to use it, and the letter giving this consent should be

submitted with the illustration.

SOURCES OF PHOTOGRAPHS.

Every photograph submitted with a manuscript should bear a memorandum

giving the name of the photographer or the owner of the negative. If

the negative is in the Survey's collection that fact should be stated,

as "Neg. Keith 318." The Survey receives many requests for copies of

photographs that have been reproduced as illustrations in its

publications, and replies to these requests will be facilitated if the

Survey's number or the source of each photograph presented for use as

an illustration is stated as above on the photograph.

LENDING ORIGINAL PHOTOGRAPHS AND DRAWINGS.

A photograph that has been used in making a half-tone cut for a Survey

report can not be lent, but if the negative is on file a print can be

furnished at cost; and a Survey drawing that is well preserved can be

photographed and a print furnished, also at cost. Requests for such

prints should be addressed to the Director.

UNPUBLISHED PHOTOGRAPHS.

The Survey can not issue a copy of an unpublished photograph except

upon the written approval or requisition of the person under whose

name the negative is filed. This requirement does not apply to a print

needed for official use, nor to a print made from an old negative

reserved under the name of any present member of the Survey or from a

negative that has been released by the person under whose name it is

filed.

Authors using Survey photographs in unofficial publications are

requested to acknowledge the source of the photograph by adding to the

printed title such a statement as "Photograph by U. S. Geological

Survey (David Whits)."

SPECIMENS.

GENERAL REQUIREMENTS.

Specimens other than fossils that are to be illustrated in a report

should be photographed before they are submitted, but the requisition

for the photographs should be initialed by the chief illustrator, who

will indicate the kinds of prints needed. Duplicate photographs of the

specimens should be made up into temporary plates by the author and

submitted with his other illustrations, the specimens being retained

subject to call, if needed, when the illustrations are finally

prepared. Should a colored illustration of a specimen be needed,

however, the specimen must be submitted with the report, and a

different kind of print, preferably one made on platinum or other

special paper, will be obtained by the section of illustrations.

BORROWED AND FRAGILE SPECIMENS.

In submitting specimens to be illustrated an author should call

attention to those that have been borrowed and to those that are

fragile. Borrowed specimens will receive first attention, so that they

may be returned promptly.

TRANSMITTAL OF PALEONTOLOGIC SPECIMENS.

All requests for paleontologic illustrations should be addressed to

the Director. The letter of transmittal should state the title of the

paper, the form of publication desired (bulletin, professional paper,

or monograph), and the status of the manuscript, whether completed or

in preparation. If the paper is unfinished an estimate of the number

of illustrations required should be given, and the special reasons for

prompt preparation should be fully stated. A letter transmitting a

second or third lot of fossils should refer to the preceding lot or

lots if all the fossils are to be used in illustrating the same paper.

Fossils that are to be drawn should be sent directly to the section

of illustrations, but those that are to be photographed and require

unusual posing or that are extremely delicate and valuable may be sent

directly to the photographic laboratory to avoid repeated handling.

Each specimen or, if it is very small, each box or bottle containing a

specimen should be numbered, and each lot should be accompanied by a

list giving their names and numbers. Full instructions as to size of

reproduction, together with sketches showing the point of view

preferred and any special features to be displayed should also be

submitted. All specimens that show strong colors and all groups of

specimens that are not uniform in color will be coated by holding them

in the vapor of ammonium chloride unless directions to the contrary

are given by the author of the paper. As it may not be desirable to

apply this process to soft or fragile specimens or to specimens that

have been borrowed an author should indicate any specimens that may

not be so treated. Specimens whose color aids in revealing detail are

not so coated. If any features of a specimen are unusual that fact

should be stated so that the photographer and the retoucher may

perform their work according to the requirements.

MAKING UP PLATES.

Two or more illustrations may be combined to form one plate in order

to permit easy and close comparison as well as for economy, for if a

particular illustration is too small to make a full plate and is not

suitable for enlargement other illustrations that are closely related

to it may be put on the same plate. The size of the printed page as

given in the table on page 11 will determine the size of the plate.

In making up plates composed of a number of figures the author should

endeavor to group related figures together and at the same time to

observe proper regard for artistic effect, but as figures vary in size

and shape a grouping according to relations may not be possible in

some plates. If related figures can not be kept together the larger

and darker figures should be placed in the lower part of the plate and

the smaller and lighter above. If a plate consists of one large figure

and several smaller ones the large figure should be placed below and

the smaller figures above.

A number designating a figure should be placed immediately below the

figure, and a series of such numbers should preferably begin with 1 in

the upper left corner and continue consecutively across and down

through the plate. This arrangement is not always possible, however,

on account of variations in the size of figures.

As drawings of fossils or other specimens are prepared separately and

grouped into plates, and as most paleontologists make up their own

plates, each in his own way, there is naturally great dissimilarity in

methods and in results. Ordinary white or light-gray cardboard should

be used, and the figures that are to make up a plate should be

arranged as stated above but not securely pasted until the grouping is

satisfactory. In trimming each drawing or photograph the author should

be careful to leave room at its lower edge for the number. Small

drawings or photographs, such as paleontologists use, when pasted on

bristol board or other board faced with tough paper are difficult or

impossible to remove without injury if they have to be remounted;

figures pasted on ordinary white or gray cardboard can be removed

without difficulty. Each plate should be made up in a size to fit the

volume or in its correct proportion to a page in the volume in which

it is to be used (see table on p. 11), and each figure should be

properly oriented--that is, all vertical lines, or the vertical axis

of each specimen, should be parallel with the sides of the plate. When

the figures are being mounted care should be taken that the mucilage

or paste does not exude under pressure and cover any part of the

drawing or photograph. The same attention should be given to pasting

on numbers. Inattention to these details may produce results that

will affect the reproduction of the plates.

Ordinary mucilage may be used for mounting drawings and photographs,

but photo paste gives good results and is perhaps cleaner to handle.

Dry-mounting tissue is well adapted to mounting single illustrations

but not groups of figures. Liquid rubber is sometimes used, but it is

not suitable for mounting small figures, such as drawings and

photographs of fossils. It can be used satisfactorily for mounting

temporary plates and for mounting photographs in albums and on large

cards for study or exhibition; but it has not proved to be a permanent

adhesive. Its special merit is that it does not cause either the

photograph or the mounting sheet to warp. It is applied by spreading

it evenly over the back of the photograph with the fingers. The

superfluous rubber can easily be removed from the hands and from the

cards or sheets when it is dry. Anything mounted with liquid rubber

can be easily removed.

If a plate is to be made up of a small number of figures that require

different reductions, the author, instead of mounting or pasting the

separate figures on one card in the manner already indicated, may draw

a rectangle of the size of the printed plate and sketch within it the

several figures in their respective sizes and positions. These "dummy"

plates or layouts should be numbered as plates, and they may bear

captions and titles. The photographs or drawings represented by the

sketches should then be numbered to identify them with the sketches on

the dummy plate, and those that pertain to each plate should be

inclosed in an envelope attached to the dummy plate. A plate made up

in this manner will meet every requirement of the photo-engraver or

lithographer.

If a paleontologist so desires, his plates can be permanently made up

after he has transmitted his material, but he should always submit a

tentative arrangement.

REUSE OF ILLUSTRATIONS.

If an author desires to use in modified form an illustration already

published, whether by the Geological Survey or by an outside

publisher, he should furnish a print or tracing of the illustration

showing the changes desired. If the illustration is not to be modified

he need only give the title of the volume in which it was used, with

the number of the page, figure, or plate, and he need not make a

sketch of the illustration or furnish a dummy; but its title should be

quoted and proper reference should be given in the list of

illustrations. Due credit should be given to the author or publisher.

The original cuts of illustrations will be kept for one year after the

report for which they were made has been published, and authors of

later reports may and should reuse, whenever practicable, any such

cut that will serve as an illustration. In the author's list of

illustrations such a cut should be referred to by its number as plate

or figure and the volume in which it was first used.

An electrotype of any cut on hand will be furnished for use in

publications other than those of the Geological Survey at the cost of

making, which is 3-1/2 to 5-1/2 cents a square inch of printing

surface. The minimum charge for a single electrotype ranges from 46 to

60 cents.

APPROVAL OF FINISHED ILLUSTRATIONS.

After the drawings for a report have been prepared they will be

submitted to the author or to the chief of his branch or division for

examination. The finished drawings will be accompanied by the

"originals," with which the author should carefully and thoroughly

compare them. After making a thorough comparison he should mark

lightly with a pencil, on the finished drawings, all necessary

corrections, or indicate his approval subject to such corrections and

additions as may be required. He should verify all type matter and

other lettering and assure himself that no mistakes have been made in

grouping the photographs into plates, especially such as have been

regrouped since they left his hands. The author's list of

illustrations will be submitted with the new drawings for this

purpose.

REVISION OF ILLUSTRATIONS.

All illustrations receive editorial revision before they are sent to

the engravers. After they are drawn they are examined with reference

to their scientific features and their accuracy, and then in turn with

reference to the correctness of geologic names and geographic names

and to errors in statement and in spelling. Each illustration thus,

before it is completed, receives critical examination by persons

qualified in particular kinds of work to detect errors or omissions.

SUBMITTAL OF PROOFS.

The first proofs of all illustrations are submitted to an author when

he is within reach, but if he is in the field and the transmittal of

the proofs to him is likely to cause too much delay they are submitted

to the chief of the branch or division in which the report was

prepared. Second proofs of the more complicated illustrations,

particularly geologic maps, may be submitted. An author's examination

should be confined principally to the revision of the scientific

features of his illustrations, but suggestions as to general

effectiveness are always acceptable.

The process to be used in engraving each illustration is stamped in

its lower left corner. In examining proofs an author should note the

following facts:

1. Changes can not be made in zinc etchings except by eliminating

parts, cutting away defects, and connecting lines. If additions are

required reengraving is generally necessary, and reengraving should

preferably be avoided.

2. Changes can be made in half-tone plates only by re-etching certain

parts to make them lighter and by burnishing certain parts to make

them darker. If the proof shows a general loss of detail the fault may

lie either in the proving of the cut or in the reproduction. If it is

in the reproduction it can not be remedied without reengraving. A

slight loss of detail may be expected in all half tones, especially in

those that are smaller than the copy submitted.

3. Minor changes can be made in photolithographs and

chromolithographs, but changes can not be made twice in one place

without danger of affecting the printing. It is customary to approve

all lithographic proofs subject to the corrections indicated, the

printed edition being examined and compared, but if the changes are

numerous and radical second proofs may be required. Second combined

proofs of chromolithographs are very expensive. (See p. 89.)

PROOF READING ILLUSTRATIONS.

An author should examine the proofs of his illustrations closely and

should compare them carefully with the original drawings. A mere

cursory examination may fail to detect errors that have not been

caught by the regular proof reader. Every correction desired should be

clearly indicated with pen and ink in the body of the proof and

inclosed in a loop from which a line should be carried to a marginal

note or comment, but if the time available is short a pencil may be

used. In correcting type matter or lettering (such as that in a

geologic legend or explanation) the ordinary proof reader's marks

should be used. The author or the person examining the proofs should

initial each one at the place indicated by a rubber stamp.

Proofs should be held only long enough to examine them properly and to

compare them with the original illustrations, for a time limit is

fixed in each contract for engraving, and if the author holds proofs

beyond a reasonable time he causes a delay in the fulfillment of the

contract.

As the illustrations for many reports contain important data that will

be discussed in the text, proofs of illustrations can not be supplied

to any applicant without consent from the Director's office.

GENERAL CONSIDERATIONS.

The following requirements are essential to obtain good original

illustrations:

1. The material selected should be pertinent and expressive; it

should have the qualities essential to good illustrations.

2. The character of the report and the size of the illustrations

should be kept clearly in mind. If the report is preliminary or

ephemeral the illustrations should be simple and inexpensive. If the

report represents the sum of knowledge on the subject treated or the

last word on some particular area the illustrations may be more

elaborate. The character of a report generally determines the form of

publication, which, in turn, determines the size of the pages and the

size of the plates and figures. Every sketch made should be larger

than publication size--preferably twice publication size--whether it

is a simple diagram or a base map.

3. The kind of reproduction that is apparently needed should be fully

considered, for it should have some relation to the kind of report.

The illustrations for short-lived reports are reproduced by the

cheaper processes. Those for hurried reports are reproduced by

processes that can be worked quickly, but no process should be

considered that will not give a clear reproduction of essential

details.

4. Clearness of preparation of original matter is invariably

essential. An author should not expect the draftsmen or the editors to

supply missing links. Each original should be complete and should be

so made that it can be understood and followed without question.

Changes made in the finished drawings or on proof sheets are expensive

and delay publication.

PART II. PREPARATION BY DRAFTSMEN.

GENERAL DIRECTIONS.

The work of preparing illustrations such as are used in the reports of

the Geological Survey is essentially that of making finished drawings

from more or less crude and imperfect material furnished by authors to

illustrate certain features or phenomena discussed in their

manuscripts. Each finished drawing must be so prepared that it can be

reproduced in multiple by one of several processes of engraving. The

author's sketches and other material are commonly called "originals";

the finished illustrations are known by the engravers as "copy."

Though most engraver's copy consists of more or less elaborate

drawings that are to be reproduced in facsimile by "direct" processes

without the interposition of handwork, some of it consists of more

roughly prepared copy which is accurate in statement but requires

complete manual or "indirect" reproduction. The direct processes in

use are zinc etching, half-tone engraving, photolithography,

three-color half tone, photogravure, and photogelatin. The manual or

indirect processes are wax engraving, wood engraving, engraving on

copper and on stone, plain lithography, and chromolithography. These

processes are described on pages 72-90.

Part I of this pamphlet contains some matter that is pertinent to

final preparation and should be consulted by draftsmen.

To prepare a drawing that will be in every way suitable for

reproduction usually requires experience of a kind not acquired in

many other kinds of drafting, such as preparing engineers' or

architects' drawings, because the drawings themselves or blue prints

made directly from them are the things the engineer or the architect

desires. Drawings prepared for reproduction are generally made larger

than publication size, and it is therefore necessary to gage each

line, letter, or feature for a definite reduction. Engineers' and

architects' drawings generally do not require preparation for

reproduction by any process, but in preparing illustrations for the

reports of the Geological Survey reproduction must be fully considered

at every step, and each drawing must be made according to the

requirements of a certain selected process and gaged for a certain

reduction. The draftsman should therefore know how to plan each

drawing step by step for an engraved cut, a lithograph, a text figure,

or a plate, always with a definite result in view. He should be

familiar with processes of engraving and should know the special

requirements of each process, and he should be able to prepare

drawings for any specified reduction in a way to insure good, legible

reproduction.

The geologic draftsman should read and study such textbooks of geology

as those of Dana and Geikie and should familiarize himself with

structural geology, the geologic time divisions, and geologic

nomenclature. He should be able to prepare a simple, effective

illustration from complicated rough originals and to supply minor

missing essential parts or features. To perform his work successfully

he must possess mechanical skill and some artistic taste, as well as

good eyesight and great patience.

INSTRUMENTS.

The following list of draftsmen's instruments is practically complete.

Those which are considered indispensable are marked by asterisks; the

others may be used according to individual preference. The same kind

of instrument may be duplicated in different sizes according to the

variation in the demands of the work.

Air brush and connections. Pens, Payzant's, 1 set.

Beam compass. *Pencils, best quality, graded

Bow pen, drop spring. leads.

*Bow pen, steel spring. *Protractor.

Bow pencil, steel spring. Railroad curves, pearwood, 1 set.

*Brushes, red sable. Railroad pen.

China saucers. *Railroad pencil.

*Color box. Reading glass.

*Compass, pen and pencil points. *Reducing glass.

Crayons, assorted colors. *Ruling pen.

Curve rule, adjustable. Scale, boxwood, 12 inches long,

*Dividers, plain. with divisions of millimeters

*Dividers, proportional. and inches.

Dividers, steel spring. Scales, boxwood, triangular.

Drawing boards, several sizes. Section liner (parallel ruling

Eraser, glass. device).

*Eraser, rubber, hard. Straightedge, steel, 24 inches.

*Eraser, rubber, soft. Straightedge, steel, 36 inches,

*Eraser, steel. with divisions for hundredths

Erasing shield. of an inch and millimeters.

*French curves, xylonite. *Straightedge, wood, 24 inches.

Microscope, low power and Swivel or curve pen.

lenses. Thumb tacks.

Palette knife. Tracing point, steel.

Pantograph. *Triangle, 45°.

Pens, double-pointed. *Triangle, 60°.

*Pens, Gillott's, Nos. 170, *T square, pearwood, xylonite edge.

290, 291. *Tweezers, dentist's.

Pens, K. & E., drawing. No. 3202.

CLASSIFICATION OF MATERIAL.

The draftsman handling the drawings and other original material

submitted by the author of a report for its illustration should first

group them, as far as possible, into kinds or classes, in order that

he may decide how each illustration should be prepared (1) to express

most effectively the author's purpose, (2) to insure reasonable

economy in preparation and in reproduction, and (3) to meet the

requirements of the processes of reproduction selected. All similar

illustrations for one publication should be prepared in the same

general style. In a series of geologic sections, for example, the same

lithologic symbols should be used throughout for the same kinds of

rocks. The titles, explanations, and captions of the maps should also

agree with one another in general style and in details of workmanship.

The draftsman should determine in advance the reduction for each

drawing or for each group of drawings, in order that he may use the

same size of letters or the same kinds of type for the lettering on a

series of drawings that require the same reduction. The reduction

should preferably be marked in fractions (as "1/2 off," "1/4 off" or

"reduce 1/2," "reduce 1/4"), and the choice of the same reduction for

a group of drawings will not only insure greater uniformity in the

drafting and in the reproduction but will permit the drawings to be

reproduced more economically, for the engraver can photograph them in

groups instead of each one separately.

The draftsman should therefore note and consider (1) the special

features shown in the author's originals; (2) whether or not these

features have been plainly indicated and whether the originals are

complete; (3) the size of the printed page of the volume in which the

illustrations will appear and the reduction required for each drawing;

and (4) the process by which each drawing should be reproduced. If an

original is of doubtful or uncertain interpretation or appears to be

incomplete the draftsman should confer with the author of the paper if

he is within reach or should bring the matter to the attention of the

chief of the branch; otherwise he may waste much time in making the

drawing.

PREPARATION OF MAPS.

PROJECTION.

The base maps furnished by authors (see pp. 13-14) are prepared in

many different ways and in different degrees of refinement and of

crudity, but the work of redrawing them for reproduction involves

well-established and generally uniform principles. All maps except

those of very extensive areas should be based on a map projection

which will show with a minimum of distortion the effect of the

curvature of the earth. The polyconic projection (see fig. 5) is used

for most Government maps. In this projection the central meridian is

a straight vertical line, and each parallel of latitude is developed

independently of the others. The mathematical elements of map

projection are given in tables published by the Geological Survey[6]

and the Coast and Geodetic Survey.[7] Figure 5, however, illustrates

the mechanical or constructional features of the polyconic projection

and if used in connection with the published tables will probably be

a sufficient guide for projecting a map on any desired scale.

[Footnote 6: Gannett, S. S., Geographic tables and formulas, 4th ed.:

U. S. Geol. Survey Bull. 650, 1916. See also Gannett, Henry, Manual of

topographic methods: U. S. Geol. Survey Bull. 307, pp. 85-86, 1906.]

[Footnote 7: Methods and results: Tables for the projection of maps

and polyconic development; Appendix No. 6, Report for 1884; Tables for

a polyconic projection of maps, based upon Clarke's reference spheroid

of 1886; 3d ed., 1910.]

[Illustration: Figure 5.--Diagram illustrating method of projecting a

map.]

In projecting a map first select a convenient measuring scale for

setting off the dimensions given in the tables, or if no scale is at

hand one may be constructed. Measuring scales are made, however,

bearing divisions for miles and kilometers and finer subdivisions of 6

to 100 parts. They include the ratios of 1:31,250, 1:31,680, 1:48,000,

1:62,500, 1:63,360, 1:125,000, 1:250,000, 1:500,000, 1:1,000,000, and

others. On a map drawn on the scale of 1 to 63,360, for example, 1

inch would represent 1 mile; on a map drawn on the scale of 1 to

1,000,000, 1 millimeter would represent 1 kilometer, and so on. It

will be seen that the use of a scale that shows in ratios, such as

those just given, the actual distance on the ground as compared with

the unit representing the same distance on the map will reduce the

possibility of error.

The method of projecting a map, illustrated in the accompanying

diagram (fig. 5), is as follows: First draw a straight vertical line

(A) through the middle of the sheet to represent the central meridian

of the map and a line (B) at the lower end of this line exactly at

right angles to it to represent the bottom of the map. Then set off on

the line showing the central meridian the distances between parallels

given in Table 6 on page 36 of "Geographic tables and formulas" (Bull.

650). It should be noted that the figures in these tables give the

distance, in meters and statute miles, of 1° on a meridian measured

30' each way from a point where the meridian is intersected by a

parallel. The exact distances between parallels as measured on the

ground are given in the Coast and Geodetic Survey tables, or they may

be computed from Table 6 of "Geographic tables and formulas" by adding

the sum of the figures given for any two latitudes 1° apart and

dividing by 2.

The distance between parallels that are 2° apart, as shown in the

diagram, may be computed from Table 6 of "Geographic tables and

formulas," as follows:

Meters. Meters.

1° of latitude on 37th parallel = 100,975.1 / 2 = 55,487.5

1° of latitude on 36th parallel = 110,956.2

1° of latitude on 35th parallel = 110,937.6 / 2 = 55,468.8

---------

True distance from 35° to 37° latitude = 221,912.5

The distances given in the diagram were obtained by adding the figures

given in the Coast and Geodetic Survey tables, which yield the same

results. Other tables in Bulletin 650 give the true distances in

inches on maps of certain standard scales.

Through the points thus obtained on the central meridian draw lines at

right angles to the vertical line. Along these horizontal lines lay

off the dimensions in the column headed X, Table 6 (pp. 39-47) of

"Geographic tables and formulas" as required for each individual

map--in the diagram every alternate degree. Draw vertical lines at

these points and set off the distance Y in the same table in a similar

manner, and the points so found will be the points of intersection of

the respective meridians and parallels. Figures are given on the

diagram for the thirty-fifth parallel only.

DETAILS OF BASE MAPS.

Anyone who attempts to draw a base map must, first of all, know how

each feature or part of the map should be represented. Most of the

conventional symbols for features shown on base maps are well

established and should invariably be used; for instance, a line

composed of alternate long and short dashes (not dashes and dots)

represents a county boundary, and a line or two parallel lines across

which short lines are drawn at regular intervals represents a

railroad. If he finds that two or more symbols have been widely used

to represent the same feature the draftsman should select the one that

is best suited to the map in hand. The correct forms of the

conventional symbols or features to be used in preparing miscellaneous

maps are shown in Plate IV, but the size and weight of each line or

symbol must depend on the size and character of the map.

TRANSFERRING OF COPYING.

TRACING.

The oldest method of transferring a map or parts of a map or other

drawing to another sheet is that of copying it by means of tracing

paper. This method, though still used for simple work, has given way

to quicker and more effective methods. By one of these methods a piece

of thin, fairly smooth paper (not necessarily transparent) is coated

with graphite by rubbing over it a soft pencil. When the graphite has

been evenly distributed over it, this sheet is laid upon the drawing

paper, coated side down, the map or other subject to be copied is laid

upon the graphite-coated sheet, and the two outer sheets--the drawing

paper and the map--are securely fastened together. By a steel tracing

point or very hard pencil the lines and other details of the matter to

be copied are then firmly and carefully traced and thus transferred to

the clean drawing paper beneath.

For maps that show several features in different colors sheets rubbed

with blue, orange, brown, or green pencils may be used, one after

another, for tracing each set of the features. Red should not be used,

as it is not easily erased. This method insures distinctive lines for

the separate features and prevents the confusion that might result

from the use of one color only. Exact register of the features shown

in the several colors used may be insured by fastening one edge of the

drawing to be copied to the drawing paper by mucilage or thumb tacks.

The colored sheets may then be slipped in and out without altering the

position of the lines or symbols for one set of data with relation to

those for the others.

In the final preparation of a base map to be engraved and printed in

colors--for example, black, blue, and brown--tracings of the three

colors appearing on the original base should generally be transferred,

as described above, to one sheet of paper and thus worked up into a

three-colored map. It is usually unnecessary and undesirable to draw

each color on a separate sheet. The preparation of separate drawings

may facilitate reproduction, but if they are made on tracing cloth the

usual uneven shrinking or stretching of the cloth may produce

misregister in the printing; therefore it is safer to make a single

drawing, so that the photolithographer can make three negatives and

separate the colors by painting out or "opaquing" the colors not

wanted on each negative. A map drawn on a single sheet is also less

bulky and can therefore be more conveniently handled and compared with

proof.

If for any reason separate tracings for the different colors to be

used on a map are considered desirable they should be made on linen

cut from one roll and in the same direction according to the warp and

woof.

CELLULOID TRANSFERRING.

In the celluloid method of transferring a map or parts of a map to

paper upon which a complete new map is to be drawn the map or part of

the map to be copied is photographed to the exact scale of the new

drawing and reproduced in graphite on thin sheets of celluloid.

The celluloid sheet is then laid face down in the correct position on

the drawing paper and firmly rubbed on the back with a steel

burnisher, which makes a perfect offset of the map on the paper. After

the parts desired are inked over the rest of the graphite print is

easily erased with an ordinary rubber.

By using this method it is possible to get absolute scale and more

satisfactory results than by tracing over a photographic print line

for line or by using a pantograph.

Requisitions for celluloid prints are made on the form used for

requesting photolithographic work.

SKETCHING BY RETICULATION.

If the sheet bearing the design or matter to be copied may be marred

without objection it is ruled lightly into pencil squares of equal

size. Corresponding squares of the same size, larger, or smaller,

according to the size of the new drawing, are then ruled on the

drawing paper, and the work is sketched square by square. If the

original sheet may not be marred the same result can be obtained by

drawing the lines on a transparent oversheet. This method is

serviceable for enlarging or reducing simple work that includes no

great amount of detail; if great precision of detail is required the

original should be enlarged or reduced by photography or by the

pantograph.

THE "SHADOWLESS DRAFTING TABLE."

One of the most useful contrivances that has been made for tracing a

drawing on the same scale is called by its manufacturers the

"shadowless drafting table." The essential features of this table are

a wooden box inclosing strong incandescent lights and bearing a

ground-glass top. A drawing placed on the ground glass can be so

illuminated as to make its lines conspicuous and readily traceable

even through relatively thick paper. The table is particularly useful

for tracing sheets upon, which the lines are indistinct and would not

be discernible under tracing paper with reflected light. It is also

useful in preparing drawings in which certain features must register

perfectly over each other. In fact any drawing that does not require

enlarging or reducing can be traced with great facility by the use of

this drafting table, and it is particularly useful for tracing faint

lines on old and poorly preserved prints or drawings.

Such a table has been installed in the section of illustrations, where

it can be used by authors and others.

TOPOGRAPHIC FEATURES.

RELIEF.

The effect of relief is expressed on a map by three methods--by

contours, by hachures, and by shading. (See fig. 6.) The first method

does not give pronounced pictorial expression of relief, though it

gives correct shape and exact elevation; the others are mow pictorial,

but they do not give exact elevation.

_Contours._--As contoured maps are originally prepared from actual

surveys the draftsman should simply follow the copy furnished by the

topographer or such original matter as may be given to him for

redrawing. If the area mapped is large and the contours are close

together the original may be transferred by celluloid tracing (see p.

47), or it may be transferred by tracing with graphite-coated paper

(see p. 46). After the contour lines have been transferred they should

be traced in ink, in lines of even thickness, except those that

represent certain fixed intervals and are to be numbered, which should

be made slightly thicker. (See fig. 6, A.) In drawing these lines some

draftsmen use an ordinary ruling pen, others the swivel pen; but

considerable practice is required in the use of either before it can

be controlled to follow precisely the penciled lines. Still other

draftsmen use the Shepard pen or an ordinary drawing pen. The swivel

pen, if expertly handled, produces a firm and even line.

Italic numbers should be used to indicate the elevation of a contour

and should be placed in an opening in the line, never between lines.

Where the lines run close together great care should be taken that

they do not touch unless the interspaces are so narrow that they must

touch and combine. The lines should be firm and even, and if the copy

or original map shows that they are uniformly very close together it

should be enlarged before the tracing is made in order to give more

freedom in drawing; but if the enlarged map is to be much reduced care

should be taken to make the lines proportionate to the reduction. A

photo-engraving of a map on which the contour lines are drawn very

close together is likely to be unsatisfactory because, though the

spaces between the lines are reduced in width, the lines themselves

may show no corresponding reduction in thickness.

[Illustration: Figure 6.--Methods of expressing relief: (A) by contour

lines, (B) by hachures, (C) by shading on stipple board, and (D) by a

brush drawing. The four examples given represent the same area. The

drawings were made twice the size of the printed cuts.]

Certain contour lines are commonly accentuated on a map, generally

every fourth or fifth line--that is, for a 10-foot interval every

50-foot line, for a 20-foot interval every 100-foot line, for a

25-foot interval every 100-foot line, for a 50-foot interval every

250-foot line, and for a 100-foot interval every 500-foot line.

_Hachuring._--The effect of relief can be produced satisfactorily by

hachuring but only by a draftsman who has had considerable

well-directed practice in that kind of drawing. In a hachured map the

light should seem to come from the west or northwest--that is, the

darker parts should be on the east or southeast side of an elevation

and the lighter parts on the west or northwest The highest elevation

should be represented by the darkest shade on the right and by a

corresponding high light on the left. The hachuring should begin at

the crest of a peak, range, or butte and be worked downward toward the

gentler slopes, the lines being drawn farther apart and made thinner

until the floor of the valley is reached and the effect of shadow is

lost by fewer and lighter lines. On a hachured map that is made from a

contoured map somewhat definite differences of elevation may be

indicated by the intervals between the strokes, and abrupt changes in

slope may be indicated by shorter and heavier lines. The strokes

should be disjointed, and they should trend at right angles to the

upper margin of a cliff and should radiate from a peak. Figure 6, B,

represents satisfactory hachuring.

_Hill shading._--Relief is more easily expressed by shading than by

hachuring. (See fig. 6, C, D.) The draftsman can best express it by

this means after he has studied contoured maps or photographs of the

region mapped, if they are available, in order that he may obtain an

idea of the details of its topography.

The special means used to produce hill shading will depend on the

character of surface of the paper on which the drawing is to be made,

the size of the map, the amount of detail and refinement of execution

desired, and the amount of reduction to be made in reproducing the

drawing. For maps on which it is desired to show some refinement of

drawing and detail, a lithographic or wax crayon can be used on paper

which has a grained surface. The draftsman must express relief

according to the information he has at hand, whether detailed or

general, and must employ methods that accord with the purpose of the

map and the mode of reproduction selected. If a shaded relief map is

to be prepared for direct reproduction by photolithography and the

shading is to be printed in a separate color the base map should be

completed first and a light photographic or blue print obtained on

which to add the relief in black lithographic crayon, to insure

perfect fitting of the relief and the base; or the relief can be

prepared on an oversheet--a semitransparent white paper with

sufficient "tooth" or grain to cut the shading up into minute dots.

The shadowless drafting table (see p. 47) is especially useful for

this purpose. On this oversheet register marks should be placed at the

four comers and at several other points, particularly at the

intersection of parallels and meridians.

For relief shading on small black and white maps Ross's hand-stipple

drawing paper may be used. (See p. 24.) By rubbing a black wax crayon

or pencil over the surface of the paper the desired effect is produced

in fine dots or in stipple, which may be varied in density of shade at

the will of the draftsman. (See fig. 6, C.) High lights can be

produced by scraping away the chalky surface of the paper. A

lithographic or wax crayon is the best medium to use on this stipple

paper, as on the paper referred to in the preceding paragraph, for the

shading produced by it is not so easily smeared as that produced in

pastel or by a graphite pencil. The object of using either the rough

paper or Boss's stipple paper for drawings that are to be reproduced

by photo-engraving is to produce a shading that is broken up into dots

of varying sizes, which is essential in such reproduction.

Belief shading for maps can also be made with a brush in flat washes

of either india ink or lampblack. Such shading should be made only

over a blue print or an impression of some kind from the map upon

which the shading or relief is to be overprinted. If the relief is

expressed on the author's original by contours the general shapes of

the relief and the drainage lines can be traced and transferred

lightly in blue lines to form a base on which to model the shading and

at the same time to make the shading fit the streams. Such a drawing

can be photographed through a screen and reproduced by half tone (see

fig. 6, D) or mezzotint as a separate plate made to overprint the map

in another color.

HYDROGRAPHY.

_General directions._--The drainage features of a map should be so

drawn as to suggest the natural courses of the streams. Streams should

not be drawn in straight, hard lines, as such lines are decidedly

unnatural and produce a crude effect. The course of a river may be

straight in general, but it is likely to be somewhat sinuous in

detail. If the streams shown on a preliminary map are drawn in a

clumsy or characterless fashion they should be redrawn with a freehand

effect or made slightly wavy, in order that they may appear more

natural. The gradual widening of streams from source to mouth should

also be shown in the drawing. On small-scale maps, where the eye can

at once see a stream through its full length, this almost

imperceptible widening can be expressed by a line of almost uniform

weight except for the stretch near the source, where it should grow

thinner and taper off. On maps which are to be reproduced directly

from drawings in black and white and which are to show both contour

lines and drainage the lines representing the streams and other water

bodies should generally be drawn freehand and slightly heavier than

the contour lines, which should be sharper and more precise.

The names of all streams or other bodies of water should be in italic

letters, those of the larger streams being lettered in capitals and

those of the smaller streams in capitals and lower-case letters. (See

"Lettering," p. 53.)

_Water lining._--The use of water lining on black and white maps

should be limited to maps on which the water areas are not readily

distinguishable from the land areas. In rough drawings that are to

serve only as copy for engravers a flat color may be used for water

areas and its conversion into water lines specified. In base maps to

be reproduced in three colors a light-blue tint may be used in lieu of

water lining, and it can be printed either flat or in a fine ruling

transferred to the stone that is to print the drainage. The engraving

of water lines is expensive, and the flat blue color should generally

be preferred.

Water lining usually consists of 30 to 45 lines on engraved or large

maps, but on small maps and sketch maps the number may be reduced as

desired. Care should be taken that the lines are as nearly parallel as

they can be made freehand and of even weight or thickness. The first

three to six lines outside the coast line should be somewhat closer

together than those farther out and should conform closely to the

coast line, but the spacing between the lines should increase and the

lines should become almost imperceptibly less conformable to the coast

line as they reach their outer limit, the last three to six being made

with the greatest care and refinement. Water-lined maps that are to be

reproduced by photographic processes should be drawn at least twice

publication size. The reduction will bring the lines closer together,

and the reproduction will show a more refined effect than could

possibly be produced by the most skillful drawing.

Good examples of water lining, such as are shown on the topographic

atlas sheets of the Survey, should be studied by draftsmen before

they undertake such work.

[Illustration: U. S. GEOLOGICAL SURVEY

PREPARATION OF ILLUSTRATIONS PLATE IV

SYMBOLS USED ON BASE MAPS]

CULTURAL FEATURES.

The cultural features represented on a map include "the works of

man"--not only cities, towns, buildings, bridges, railroads, and other

roads, but State, county, and other boundary lines--in short, all that

part of a three-color base map which is shown in black, the engraved

plate for the black being called the culture plate. The features named

in the list below are the cultural features referred to. (See PL IV

for corresponding symbols.)

Aqueduct mains.

Aqueduct tunnels.

Bench marks.

Boundary Lines.

Boundary monuments.

Breakwaters.

Bridges.

Buildings.

Cable Lines.

Camps.

Canal locks.

Canals.

Cemeteries.

Churches.

Cities.

County lines.

Dams.

District lines.

Ditches.

Electric power lines.

Fences.

Ferries.

Fords.

Gas wells.

Hedges.

Hospitals.

Jetties.

Land-grant lines.

Land-section Lines.

Levees.

Mains.

Mineral monuments.

Mine tunnels.

Mines.

National forests.

National parks.

Oil tanks.

Oil wells.

Open cuts.

Park boundaries.

Paths.

Pits.

Post offices.

Precinct lines.

Prospects.

Province lines.

Quarries.

Quarter-section lines.

Railroads, steam or electric.

Ranches.

Reservation boundaries.

Reservoirs.

Roads.

Ruins.

Schoolhouses.

Section comers.

Section Lines.

Settlements.

Shafts.

Streets.

Telegraph Lines.

Towns.

Township comers.

Townships.

Trails.

Tramways.

Triangulation stations.

Tunnels.

Villages.

Water mains.

Water wells.

Waterworks.

Windmills.

LETTERING.

GENERAL DIRECTIONS.

The cultural features are named on maps by letters of two distinct

styles--slanting gothic for public works and roman for habitations and

civil divisions. The size of the letters used should indicate in a

general way the relative importance of the feature or group to which

they are applied, but on some maps the county seats, State capitals,

and large cities may be distinguished by different symbols. The names

of civil divisions are lettered in sizes depending on their relative

grade and the size of the area or space in which the names are to

appear.

The features shown on a topographic map may be broadly separated into

four groups and are lettered as follows:

Civil divisions (countries, States, counties, townships, land grants,

reservations, cities, towns, villages, settlements, schools, lodges,

ranches, etc.), roman capitals or capitals and lower case.

Public works (railroads, tunnels, roads, canals, ferries, bridges,

fords, dams, mains, mines, forts, trails, etc.), slanting gothic

capitals (light) or capitals and lower case.

Hydrographic features (oceans, seas, gulfs, bays, lakes, ponds,

rivers, creeks, brooks, springs, wells, falls, rapids, marshes,

glaciers, etc.), italic capitals or capitals and lower case.

Hypsographic features (mountains, ranges, peaks, plateaus, cliffs,

buttes, canyons, valleys, peninsulas, islands, capes, etc.), upright

gothic capitals (light) or capitals and lower case.

The essential principles of lettering have been described in numerous

treatises and are well understood by most draftsmen. The correct form

of each letter may be learned from such treatises, but spacing and

arrangement are best learned by observation and experience. Good

lettering will not strongly attract attention, but even slight

imperfections of form, spacing, slant, and shading will be quickly

detected and criticized. Map letterers should note that the name of a

place or the number of a symbol should be put to the right of the

symbol if possible and a little above or below it--not to the left and

directly on a line with it, as Tucson=o=, 17=o=, Dallas=o=, Carson=o=.

Names indicating large areas, if written from west to east, should

curve with the parallels, and all names should be so lettered that "if

they should fall they would fall on their feet." Every name should be

distinctly legible but not so conspicuous as to subordinate the

feature it designates. Lines should therefore not be broken in order

to make the lettering clear except where there is possible danger that

the smaller spaces may be filled up in printing. The lettering on a

map should always be so spaced that it will properly fit the area it

is intended to designate. In names consisting of two or more words the

letters should not be closely spaced if wide spaces are left between

the words. In numbers, except those used to indicate elevations on

contour Lines or elsewhere, thousands should always be set off by

commas.

Draftsmen often draw bad forms for commas, quotation marks,

apostrophes, and question marks. The following forms are correct:

Comma , ; quotation marks "" ; apostrophe ' ; question mark ? .

LETTERING BY TYPE.

Names and short notes printed from type on paper, to be cut out and

pasted in proper positions on maps or other drawings, now furnish a

large proportion of the lettering on the Survey's illustrations. The

strips are likely to become detached by the repeated handling of a

drawing, however, unless they are securely pasted on. The best results

can be obtained by having the type printed on a special brand of

"noncurling" gummed paper, from which the lettering is cut in squares

or strips, which are dampened and applied to the proper places on the

drawing. In handling such strips a pair of dentist's tweezers is

useful. When mucilage is applied to printed strips of ordinary paper

the moisture causes the paper to warp or curl, often so much as to

affect the reproduction of the drawing. This printed lettering is

generally used, however, only for headings, titles, notes, and other

matter that stands alone; it should not be used for the geographic

names in the body of a map unless only a few names are to appear, for

the strips of paper bearing the names may obscure parts of the map.

The reproduction of this lettering by photo-engraving or

photolithography gives results superior to those obtained from hand

lettering unless each letter is made with the utmost care, work which

is considered a waste of time.

[Illustration: U. S. GEOLOGICAL SURVEY

PREPARATION OF ILLUSTRATIONS PLATE V

REDUCTION SHEET USED IN LETTERING ILLUSTRATIONS.

The largest size shows the letters unreduced; the other sizes show

the letters reduced as indicated in the margin.]

Type is used also for printing lettering directly on a drawing exactly

in proper position, by a special type holder, somewhat like a

self-inking stamp.

Most of the styles and sizes of type now used on maps in the Survey's

reports are shown in Plate V.

If a drawing is to be reduced one-half the smallest type used should

be about 2 millimeters in height; if it is to be reduced one-third the

smallest type used should be about 1.5 millimeters in height; and so

on. No letter whose vertical height after reproduction would be less

than about 1 millimeter should be used, and the larger lettering

should bear a proper relation to the smaller. Sheets showing the

styles of type in use by the Survey, in full size and reduced

one-fourth, one-third, two-fifths, one-half, three-fifths, two-thirds,

and three-fourths, will be furnished on request. If a drawing is to be

reduced one-half, for example, the sheet that has been reduced

one-half will show the size of the lettering on the printed plate, so

that the draftsman, by referring to the sheet showing the reduction he

desires, can select type of a size that will be legible. Plate V shows

a part of this reduction sheet.

ABBREVIATIONS.

The following are the correct forms for abbreviations used on maps and

other illustrations:

A. Arroyo.

B. M. Bench mark.

Bdy. Boundary.

Br. Branch, bridge.

C. Cape.

Can. Canal, canyon.

Cem. Cemetery.

Co. County.

Cr. Creek.

E. East.

El. Elevation.

Est. Estuary.

Fk. Fork.

Ft. Fort, foot.

Gl. Gulch, glacier.

Hrb. Harbor.

I. Island.

Is. Islands.

Jc. Junction.

L. Lake.

Lat. Latitude.

Ldg. Landing.

L. S. S. Life-saving station.

L. H. Lighthouse.

Long. Longitude.

M. P. Milepost.

M. M. Mineral monument.

Mt. Mount.

Mtn. Mountain.

Mts. Mountains.

N. North.

Pen. Peninsula.

Pk. Peak.

P. O. Post office.

Pt. Point.

R. Range, river.

Res. Reservation, reservoir.

R. H. Road house.

S. South.

Sd. Sound.

S. H. Schoolhouse.

Sta. Station.

Str. Stream.

T. Township.

Tel. Telegraph.

W. West.

Words like mount, river, point should not be abbreviated where they

form a part of the name of a city or town, as Rocky Mount, Fall River,

West Point. Neither the word nor the abbreviation for railroad or

railway should be placed on a map; the chartered name (or initials of

the name) and the road symbol are sufficient.

Names of States and Territories should be abbreviated, where

abbreviation is necessary, as follows:

Ala. Ga. Minn. N. J. Tenn.

Ariz. Ill. Miss. N. Mex. Tex.

Ark. Ind. Mo. N. Y. Va.

Calif. Kans. Mont. Okla. Vt.

Colo. Ky. Nebr. Oreg. Wash.

Conn. La. Nev. Pa. W. Va

D. C. Mass. N. C. R. I. Wis.

Del. Md. N. Dak. S. C. Wyo.

Fla. Mich. N. H. S. Dak.

Alaska, Guam, Hawaii, Idaho, Iowa, Maine, Ohio, Samoa, and Utah should

be written in full.

The abbreviations used on the margins of maps for subdivisions of land

should be as follows (note punctuation): T. 2 N., E. 3 W. On

large-scale plats the marginal lettering should be as follows: N. 1/2

NE. 1/4 sec. 1, T. 7 N., K 2 W.; fractional secs. 2 and 35, Tps. 7 and

8 N., R. 2 W.; NW. 1/4 sec. 20, T, 7 N., R. 2 W. In spelling fractions

use half and quarter, not one-half and one-quarter.

The abbreviated forms of such names as North Fork and South Fork

should be N. Fork and S. Fork, not North Fk. and South Fk.

Additional abbreviations used on illustrations are as follows: