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Transcriber’s note:
Text enclosed by underscores is in italics (_italics_).
Text enclosed by equal signs is in bold face (=bold=).
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EARTH FEATURES AND THEIR MEANING
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EARTH FEATURES AND THEIR MEANING
An Introduction to Geology for the Student and the General Reader
by
WILLIAM HERBERT HOBBS
Professor of Geology in the University of Michigan
Author of “Earthquakes. an Introduction to Seismic Geology”;
“Characteristics of Existing Glaciers”; etc.
New York
The Macmillan Company
1921
All rights reserved
Copyright, 1912,
By The Macmillan Company.
Norwood Press
J. S. Cushing Co.—Berwick & Smith Co.
Norwood, Mass., U.S.A.
TO THE MEMORY
OF
GEORGE HUNTINGTON WILLIAMS
PREFACE
THE series of readings contained in the present volume give in somewhat
expanded form the substance of a course of illustrated lectures
which has now for several years been delivered each semester at the
University of Michigan. The keynote of the course may be found in
the dominant characteristics of the different earth features and the
geological processes which have been betrayed in the shaping of them.
Such a geological examination of landscape is replete with fascinating
revelations, and it lends to the study of Nature a deep meaning which
cannot but enhance the enjoyment of her varied aspects.
That there is a real place for such a cultural study of geology within
the University is believed to be shown by the increasing number of
students who have elected the work. Even more than in former years the
American travels afar by car or steamship, and the earth’s surface
features in all their manifold diversity are thus one after the other
unrolled before him. The thousands who each year cross the Atlantic
to roam over European countries may by historical, literary, or
artistic studies prepare themselves to derive an exquisite pleasure
as they visit places identified with past achievement of one form or
another. Yet the Channel coast, the gorge of the Rhine, the glaciers of
Switzerland, and the wild scenery of Norway or Scotland have each their
fascinating story to tell of a history far more remote and varied. To
read this history, the runic characters in which it is written must
first of all be mastered; for in every landscape there are strong
individual lines of character such as the pen artist would skillfully
extract for an outline sketch. Such _character profiles_ are often many
times repeated in each landscape, and in them we have a key to the
historical record.
An object of the present readings has thus been to enable the
student to himself pick out in each landscape these more significant
lines and so read directly from Nature. In the landscapes which
have been represented, the aim has been to draw as far as possible
upon localities well known to travelers and likely to be visited,
either because of their historical interest or their purely scenic
attractions. It should thus be possible for a tourist in America or
Europe to pursue his landscape studies whenever he sets out upon his
travels. The better to aid him in this endeavor, some suggestions
concerning the itinerary of journeys have been supplied in an appendix.
Regarded as a textbook of geology, the present work offers some
departures from existing examples. Though it has been customary to
combine in a single text historical with dynamical and structural
geology, a tendency has already become apparent to treat the historical
division apart from the others. Again, a desire to treat the science
of geology comprehensively has led some authors into including so
many subjects as to render their texts unnecessarily encyclopedic
and correspondingly uninteresting to the general reader. It is the
author’s belief that there is a real need for a book which may be read
intelligently by the general public, and it must be recognized that
the beginner in the subject cannot cover the entire field by a single
course of readings. The present work has, therefore, been prepared with
a view to selecting for study those dominant geological processes which
are best illustrated by features in northern North America and Europe.
It is this desire to illustrate the readings by travels afield, which
accounts for the prominence given to the subject of glaciation; for the
larger number of colleges and universities in both America and Europe
are surrounded by the heavy accumulations that have resulted from
former glaciations.
Emphasis has also been placed upon the dependence of the dominant
geological processes of any region upon existing climatic conditions,
a fact to which too little attention has generally been given. This
explains the rather full treatment of desert regions, of which,
in our own country particularly, much may be illustrated upon the
transcontinental railway journeys.
More than in most texts the attempt has here been made to teach
directly through the eye with the efficient aid of apt illustrations
intimately interwoven with the text. For such success as has been
reached in this endeavor, the author is greatly indebted to two
students of the University of Michigan,—Mr. James H. Meier, who has
prepared the line drawings of landscapes, and Mr. Hugh M. Pierce, who
has draughted the diagrams. Though credit has in most cases been given
where illustrations have been made from another’s photographs, yet
especial mention should here be made of the debt to Dr. H. W. Fairbanks
of Berkeley, California, whose beautiful and instructive photographs
are reproduced upon many a page.
As given at the University of Michigan, the lectures reflected in the
present volume are supplemented by excursions and by so much laboratory
practice as is necessary to become familiar with the more common
minerals and rocks, and to read intelligently the usual topographical
and geological maps. In the appendices the means for carrying out such
studies, in part with newly devised apparatus, have been indicated.
The scope of the book precludes the possibility of furnishing the
reader with the sources for the body of fact and theory which is
presented, although much may be inferred from the names which appear
beneath the illustrations, and more definite knowledge will be found in
the references to literature supplied at the ends of chapters. A large
amount of original and unpublished material is for a similar reason
unlabeled, and it has been left for the professional geologist to
detect these new strands which have been drawn into the web.
WILLIAM HERBERT HOBBS.
ANN ARBOR, MICHIGAN,
October 25, 1911.
CONTENTS
CHAPTER I
THE COMPILATION OF EARTH HISTORY
PAGE
The sources of the history—Subdivisions of geology—The
study of earth features and their significance—Tabular
recapitulation—Geological processes not universal—Change, and not
stability, the order of nature—Observational geology _versus_
speculative philosophy—The scientific attitude and temper—The
value of the hypothesis—Heading references 1
CHAPTER II
THE FIGURE OF THE EARTH
The lithosphere and its envelopes—The evolution of ideas
concerning the earth’s figure—The oblateness of the earth—The
arrangement of oceans and continents—The figure toward
which the earth is tending—Astronomical _versus_ geodetic
observations—Changes of figure during contraction of a spherical
body—The earlier figures of the earth—The continents and
oceans at the close of the Paleozoic era—The flooded portions
of the present continents—The floors of the hydrosphere and
atmosphere—Reading references 8
CHAPTER III
THE NATURE OF THE MATERIALS IN THE LITHOSPHERE
The rigid quality of our planet—Probable composition of the
earth’s core—The earth a magnet—The chemical constitution of
the earth’s surface shell—The essential nature of crystals—The
lithosphere a complex of interlocking crystals—Some properties of
natural crystals, minerals—The alterations of minerals—Reading
references 20
CHAPTER IV
THE ROCKS OF THE EARTH’S SURFACE SHELL
The processes by which rocks are formed—The marks of origin—The
metamorphic rocks—Characteristic textures of the igneous
rocks—The classification of rocks—Subdivisions of the sedimentary
rocks—The different deposits of ocean, lake, and river—Special
marks of littoral deposits—The order of deposition during a
transgression of the sea—The basins of deposition of earlier
ages—The deposits of the deep sea—Reading references 30
CHAPTER V
CONTORTIONS OF THE STRATA WITHIN THE ZONE OF FLOW
The zones of fracture and flow—Experiments which illustrate
the fracture and flow of solid bodies—The arches and troughs
of the folded strata—The elements of folds—The shapes of rock
folds—The overthrust fold—Restoration of mutilated folds—The
geological map and section—Measurement of the thickness of
formations—The detection of plunging folds—The meaning of an
unconformity—Reading references 40
CHAPTER VI
THE ARCHITECTURE OF THE FRACTURED SUPERSTRUCTURE
The system of the fractures—The space intervals of joints—The
displacements upon joints: faults—Methods of detecting faults—The
base of the geological map—The field map and the areal geological
map—Laboratory models for study of geological maps—The method of
preparing the map—Fold _vs._ fault topography—Reading references 55
CHAPTER VII
THE INTERRUPTED CHARACTER OF EARTH MOVEMENTS: EARTHQUAKES AND
SEAQUAKES
Nature of earthquake shocks—Seaquakes and seismic sea waves—The
grander and the lesser earth movements—Changes in the earth’s
surface during earthquakes: faults and fissures—The measure
of displacement—Contraction of the earth’s surface during
earthquakes—The plan of an earthquake fault—The block movements
of the disturbed district—The earth blocks adjusted during the
Alaskan earthquake of 1899 67
CHAPTER VIII
THE INTERRUPTED CHARACTER OF EARTH MOVEMENTS: EARTHQUAKES AND
SEAQUAKES (_concluded_)
Experimental demonstration of earth movements—Derangement of
water flow by earth movement—Sand or mud cones and craterlets—The
earth’s zones of heavy earthquake—The special lines of heavy
shock—Seismotectonic lines—The heavy shocks above loose
foundations—Construction in earthquake regions—Reading references 81
CHAPTER IX
THE RISE OF MOLTEN ROCK TO THE EARTH’S SURFACE; VOLCANIC
MOUNTAINS OF EXUDATION
Prevalent misconceptions about volcanoes—Early views concerning
volcanic mountains—The birth of volcanoes—Active and extinct
volcanoes—The earth’s volcano belts—Arrangement of volcanic
vents along fissures, and especially at their intersections—The
so-called fissure eruptions—The composition and the properties of
lava—The three main types of volcanic mountain—The lava dome—The
basaltic lava domes of Hawaii—Lava movements within the caldron
of Kilauea—The draining of the lava caldrons—The outflow of the
lava floods 94
CHAPTER X
THE RISE OF MOLTEN ROCK TO THE EARTH’S SURFACE; VOLCANIC
MOUNTAINS OF EJECTED MATERIALS
The mechanics of crater explosions—Grander volcanic eruptions
of cinder cones—The eruption of Volcano in 1888—The eruption of
Taal volcano on January 30, 1911—The materials and the structure
of cinder cones—The profile lines of cinder cones—The composite
cone—The caldera of composite cones—The eruption of Vesuvius
in 1906—The sequence of events within the chimney—The spine of
Pelé—The aftermath of mud flows—The dissection of volcanoes—The
formation of lava reservoirs—Character profiles—Reading
references 115
CHAPTER XI
THE ATTACK OF THE WEATHER
The two contrasted processes of weathering—The rôle of the
percolating water—Mechanical results of decomposition:
spheroidal weathering—Exfoliation or scaling—Dome structure
in granite masses—The prying work of frost—Talus—Soil flow in
the continued presence of thaw water—The splitting wedges of
roots and trees—The rock mantle and its shield in the mat of
vegetation—Reading references 149
CHAPTER XII
THE LIFE HISTORIES OF RIVERS
The intricate pattern of river etchings—The motive power of
rivers—Old land and new land—The earlier aspects of rivers—The
meshes of the river network—The upper and lower reaches
of a river contrasted—The balance between degradation and
aggradation—The accordance of tributary valleys—The grading of
the flood plain—The cycles of stream meanders—The cut-off of the
meander—Meander scars—River terraces—The delta of the river—The
levee—The sections of delta deposits 158
CHAPTER XIII
EARTH FEATURES SHAPED BY RUNNING WATER
The newly incised upland and its sharp salients—The stage of
adolescence—The maturely dissected upland—The Hogarthian line of
beauty—The final product of river sculpture: the peneplain—The
river cross sections of successive stages—The entrenchment of
meanders with renewed uplift—The valley of the rejuvenated
river—The arrest of stream erosion by the more resistant
rocks—The capture of one river by another—Water and wind
gaps—Character profiles—Reading references 169
CHAPTER XIV
THE TRAVELS OF THE UNDERGROUND WATER
The descent within the unsaturated zone—The trunk channels
of descending water—The caverns of limestones—Swallow holes
and limestone sinks—The sinter deposits—The growth of
stalactites—Formation of stalagmites—The Karst and its features—A
desert from the destruction of forests—The ponore and the
polje—The return of the water to the surface—Artesian wells—Hot
springs and geysers—The deposition of siliceous sinter by plant
growth—Reading references 180
CHAPTER XV
SUN AND WIND IN THE LANDS OF INFREQUENT RAINS
The law of the desert—The self-registering gauge of past
climates—Some characteristics of the desert waste—Dry weathering:
the red and brown desert varnish—The mechanical breakdown of the
desert rocks—The natural sand blast—The dust carried out of the
desert 197
CHAPTER XVI
THE FEATURES IN DESERT LANDSCAPES
The wandering dunes—The forms of dunes—The cloudburst in the
desert—The zone of the dwindling river—Erosion in and about the
desert—Characteristic features of the arid lands—The war of dune
and oasis—The origin of the high plains which front the Rocky
Mountains—Character profiles—Reading references 209
CHAPTER XVII
REPEATING PATTERNS IN THE EARTH RELIEF
The weathering processes under control of the fracture system—The
fracture control of the drainage lines—The repeating pattern in
drainage networks—The dividing lines of the relief patterns:
lineaments—The composite repeating patterns of the higher
orders—Reading references 223
CHAPTER XVIII
THE FORMS CARVED AND MOLDED BY WAVES
The motion of a water wave—Free waves and breakers—Effect
of the breaking wave upon a steep, rocky shore: the notched
cliff—Coves, sea arches, and stacks—The cut rock terrace—The
cut and built terrace on a steep shore of loose materials—The
work of the shore current—The sand beach—The shingle beach—Bar,
spit, and barrier—The land-tied island—A barrier series—Character
profiles—Reading references 231
CHAPTER XIX
COAST RECORDS OF THE RISE OR FALL OF THE LAND
The characters in which the record has been preserved—Even
coast line the mark of uplift—A ragged coast line the mark of
subsidence—Slow uplift of the coasts; the coastal plain and
cuesta—The sudden uplifts of the coast—The upraised cliff—The
uplifted barrier beach—Coast terraces—The sunk or embayed
coast—Submerged river channels—Records of an oscillation of
movement—Simultaneous contrary movements upon a coast—The
contrasted islands of San Clemente and Santa Catalina—The Blue
Grotto of Capri—Character profiles—Reading references 245
CHAPTER XX
THE GLACIERS OF MOUNTAIN AND CONTINENT
Conditions essential to glaciation—The snow-line—Importance
of mountain barriers in initiating glaciers—Sensitiveness of
glaciers to temperature changes—The cycle of glaciation—The
advancing hemicycle—Continental and mountain glaciers
contrasted—The nourishment of glaciers—The upper and lower cloud
zones of the atmosphere 261
CHAPTER XXI
THE CONTINENTAL GLACIERS OF POLAR REGIONS
The inland ice of Greenland—The mountain rampart and its
portals—The marginal rock islands—Rock fragments which travel
with the ice—The grinding mill beneath the ice—The lifting
of the grinding tools and their incorporation within the
ice—Melting upon the glacier margins in Greenland—The marginal
moraines—The outwash plain or apron—The continental glacier
of Antarctica—Nourishment of continental glaciers—The glacier
broom—Field and pack ice—The drift of the pack—The Antarctic
shelf ice—Icebergs and snowbergs and the manner of their
birth—Reading references 271
CHAPTER XXII
THE CONTINENTAL GLACIERS OF THE “ICE AGE”
Earlier cycles of glaciation—Contrast of the glaciated and
nonglaciated regions—The “driftless area”—Characteristics of
the glaciated regions—The glacier gravings—Younger records over
older: the glacier palimpsest—The dispersion of the drift—The
diamonds of the drift—Tabulated comparison of the glaciated and
nonglaciated regions—Unassorted and assorted drift—Features into
which the drift is molded—Marginal or “kettle” moraines—Outwash
plains—Pitted plains and interlobate moraines—Eskers—Drumlins—The
shelf ice of the ice age—Character profiles 297
CHAPTER XXIII
GLACIAL LAKES WHICH MARKED THE DECLINE OF THE LAST ICE AGE
Interference of glaciers with drainage—Temporary lakes due to ice
blocking—The “parallel roads” of the Scottish glens—The glacial
Lake Agassiz—Episodes of the glacial lake history within the St.
Lawrence Valley—The crescentic lakes of the earlier stages—The
early Lake Maumee—The later Lake Maumee—Lakes Arkona and
Whittlesey—Lake Warren—Lakes Iroquois and Algonquin—The Nipissing
Great Lakes—Summary of lake stages—Permanent changes of drainage
effected by the glacier—Glacial Lake Ojibway in the Hudson’s Bay
drainage basin—Reading references 320
CHAPTER XXIV
THE UPTILT OF THE LAND AT THE CLOSE OF THE ICE AGE
The response of the earth’s shell to its ice mantle—The
abandoned strands as they appear to-day—The records of uplift
about Mackinac Island—The present inclinations of the uplifted
strands—The hinge lines of uptilt—Future consequences of the
continued uptilt within the lake region—Gilbert’s prophecy of a
future outlet of the Great Lakes to the Mississippi—Geological
evidences of continued uplift—Drowning of southwestern shores of
Lakes Superior and Erie—Reading references 340
CHAPTER XXV
NIAGARA FALLS A CLOCK OF RECENT GEOLOGICAL TIME
Features in and about the Niagara gorge—The drilling of the
gorge—The present rate of recession—Future extinction of the
American Fall—The captured Canadian Fall at Wintergreen Flats—The
Whirlpool Basin excavated from the St. David’s gorge—The shaping
of the Lewiston Escarpment—Episodes of Niagara’s history and
their correlation with those of the glacial lakes—Time measures
of the Niagara clock—The horologe of late glacial time in
Scandinavia—Reading references 352
CHAPTER XXVI
LAND SCULPTURE BY MOUNTAIN GLACIERS
Contrasted sculpturing of continental and mountain glaciers—Wind
distribution of the snow which falls in mountains—The niches
which form on snowdrift sites—The augmented snowdrift moves
down the valley: birth of the glacier—The excavation of the
glacial amphitheater or cirque—Life history of the cirque—Grooved
and fretted uplands—The features carved above the glacier—The
features shaped beneath the glacier—The cascade stairway in
glacier-carved valleys—The character profiles which result from
sculpture by mountain glaciers—The sculpture accomplished by ice
caps—The Norwegian tind or beehive mountain—Reading references 367
CHAPTER XXVII
SUCCESSIVE GLACIER TYPES OF A WANING GLACIATION
Transition from the ice cap to the mountain glacier—The piedmont
glacier—The expanded-foot glacier—The dendritic glacier—The
radiating glacier—The horseshoe glacier—The inherited-basin
glacier—Summary of types of mountain glacier—Reading references 383
CHAPTER XXVIII
THE GLACIER’S SURFACE FEATURES AND THE DEPOSITS UPON ITS BED
The glacier flow—Crevasses and séracs—Bodies given up by the
_Glacier des Bossons_—The moraines—Selective melting upon
the glacier surface—Glacier drainage—Deposits within the
vacated valley—Marks of the earlier occupation of mountains by
glaciers—Reading references 390
CHAPTER XXIX
A STUDY OF LAKE BASINS
Fresh water and saline lakes—Newland lakes—Basin-range
lakes—Rift-valley lakes—Earthquake lakes—Crater lakes—Coulée
lakes—Morainal lakes—Pit lakes—Glint or colk lakes—Ice-dam
lakes—Glacier-lobe lakes—Rock-basin lakes—Valley moraine
lakes—Landslide lakes—Border lakes—Ox-bow lakes—Saucer
lakes—Crescentic levee lakes—Raft lakes—Side-delta lakes—Delta
lakes—Barrier lakes—Dune lakes—Sink lakes—Karst lakes:
_poljen_—Playa lakes—Salines—Alluvial-dam lakes—Résumé—Reading
references 401
CHAPTER XXX
THE EPHEMERAL EXISTENCE OF LAKES
Lakes as settling basins—Drawing off of water by erosion of
outlet—The pulling in of headlands and the cutting off of
bays—Lake extinction by peat growth—Extinction of lakes in desert
regions—The rôle of lakes in the economy of nature—Ice ramparts
on lake shores—Reading references 426
CHAPTER XXXI
THE ORIGIN AND THE FORMS OF MOUNTAINS
A mountain defined—The festoons of mountain arcs—Theories of
origin of the mountain arcs—The Atlantic and Pacific coasts
contrasted—The block type of mountain—Mountains of outflow
or upheap—Domed mountains of uplift; laccolites—Mountains
carved from plateaus—The climatic conditions of the mountain
sculpture—The effect of the resistant stratum—The mark of the
rift in the eroded mountains—Reading references 435
APPENDICES
A. The quick determination of the common minerals 449
B. Short descriptions of some common rocks 462
C. The preparation of topographical maps 467
D. Laboratory models for study in the interpretation of
geological maps 472
E. Suggested itineraries for pilgrimages to study earth features 475
INDEX 489
LIST OF PLATES
PLATE
1. Mount Balfour and the Balfour Glacier in the Selkirks
_Frontispiece_
FACING PAGE
2. A. Layers compressed in experiments and showing the effect of
a competent layer in the process of folding 44
B. Experimental production of a series of parallel thrusts
within closely folded strata 44
C. Apparatus to illustrate shearing action within the
overturned limb of a fold 44
3. A. An earthquake fault opened in Formosa in 1906 with vertical
and lateral displacements combined 72
B. Earthquake faults opened in Alaska in 1889 on which
vertical slices of the earth’s shell have undergone
individual adjustments 72
4. A. Experimental tank to illustrate the earth movements which
are manifested in earthquakes. The sections of the earth’s
shell are here represented before adjustment has taken
place 82
B. The same apparatus after a sudden adjustment 82
C. Model to illustrate a block displacement in rocks which are
intersected by master joints 82
5. A. Once wooded region in China now reduced to desert through
deforestation 156
B. “Bad Lands” in the Colorado Desert 156
6. A. Barren Karst landscape near the famous Adelsberg grottoes 188
B. Surface of a limestone ledge where joints have been
widened through solution 188
7. A. Ranges of dunes upon the margin of the Colorado Desert 210
B. Sand dunes encroaching upon the oasis of Oued Souf, Algeria 210
8. A. The granite needles of Harney Peak in the Black Hills of
South Dakota 216
B. Castellated erosion chimneys in El Cobra Cañon, New Mexico 216
9. Map of the High Plains at the eastern front of the Rocky
Mountains 220
10. A. View in Spitzbergen to illustrate the disintegration of
rock under the control of joints 228
B. Composite pattern of the joint structures within recent
alluvial deposits of the Syrian Desert 228
11. A. Ripple markings within an ancient sandstone 232
B. Wave breaking as it approaches the shore 232
12. A. V-shaped cañon cut in an upland recently elevated from the
sea, San Clemente Island, California 256
B. A “hogback” at the base of the Bighorn Mountains, Wyoming 256
13. A. Precipitous front of the Bryant Glacier outlet of the
Greenland inland ice 272
B. Lateral stream beside the Benedict Glacier outlet,
Greenland 272
14. View of the margin of the Antarctic continental glacier in
Kaiser Wilhelm Land 282
15. A. An Antarctic ice foot with boat party landing 290
B. A near view of the front of the Great Ross Barrier,
Antarctica 290
16. A. Incised topography within the “driftless area” 300
B. Built-up topography within the glaciated region 300
17. A. Soled glacial bowlders which show differently directed
striæ upon the same facet 306
B. Perched bowlder upon a striated ledge of different rock
type, Bronx Park, New York 306
C. Characteristic knob and basin surface of a moraine 306
18. A. Fretted upland of the Alps seen from the summit of Mount
Blanc 372
B. Model of the Malaspina Glacier and the fretted upland
above it 372
19. A. Contour map of a grooved upland, Bighorn Mountains,
Wyoming 372
B. Contour map of a fretted upland, Philipsburg Quadrangle,
Montana 372
20. Map of the surface modeled by mountain glaciers in the Sierra
Nevadas of California 376
21. A. View of the Harvard Glacier, Alaska, showing the
characteristic terraces 394
B. The terminal moraine at the foot of a mountain glacier 394
22. A. Model of the vicinity of Chicago, showing the position of
the outlet of the former Lake Chicago 400
B. Map of Yosemite Falls and its earlier site near Eagle Peak 400
23. A. View of the American Fall at Niagara, showing the
accumulation of blocks beneath 414
B. Crystal Lake, a landslide lake in Colorado 414
24. A. Apparatus for exercise in the preparation of topographic
maps 468
B. The same apparatus in use for testing the contours of a map 468
C. Modeling apparatus in use 468
ILLUSTRATIONS IN THE TEXT
FIG. PAGE
1. Diagram to show the measure of the earth’s surface
irregularities 11
2. Map to show the reciprocal relation of areas of land and sea 11
3. The tetrahedral form toward which the earth is tending 12
4. A truncated tetrahedron to show the reciprocal relation of
projection and depression upon the surface 13
5. Approximations to earlier and present figures of the earth 15
6. Diagrams for comparison of coasts upon an upright and upon an
inverted tetrahedron 17
7. The continents, including submerged portions 18
8. Diagram to indicate the altitude of different parts of the
lithosphere surface 18
9. Diagram to show how the terrestrial rocks grade into the
meteorites 22
10. Comparison of a crystalline with an amorphous substance 24
11. “Light figure” seen upon etched surface of calcite 25
12. Battered sand grains which have developed crystal faces 26
13. Unassimilated grains of quartz within a garnet crystal 28
14. New minerals developed about the core of an augite crystal 28
15. A common rim of new mineral developed by reaction where
earlier minerals come into contact 28
16. Laminated structure of a sedimentary rock 30
17. Characteristic textures of igneous rocks 33
18. Diagram to show the order of sediments laid down during a
transgression of the sea 37
19. Fractures produced by compression of a block of molder’s wax 41
20. Apparatus to illustrate the folding of strata 41
21. Diagrams of fold types 42
22. Diagrams to illustrate crustal shortening 42
23. Anticlinal and synclinal folds 43
24. Diagrams to illustrate the shapes of rock folds 44
25. Secondary and tertiary flexures superimposed upon the
primary ones 44
26. A bent stratum to illustrate tension and compression upon
opposite sides 45
27. A geological section with truncated arches restored 47
28. Diagram to illustrate the nature of strike and dip 47
29. Diagram to show the use of T symbols for strike and dip
observation 48
30. Diagram to show how the thickness of a formation is
determined 49
31. A plunging anticline 50
32. A plunging syncline 50
33. An unconformity upon the coast of California 51
34. Series of diagrams to illustrate the episodes involved in
the production of an angular unconformity 52
35. Types of deceptive or erosional unconformities 53
36. A set of master joints in shale 55
37. Diagram to show the manner of replacement of one set of
joints by another 56
38. Diagram to show the different combinations of joint series 56
39. View of the shore in West Greenland 57
40. View in Iceland which shows joint intervals of more than one
order 57
41. Faulted blocks of basalt near Woodbury, Connecticut 58
42. A fault in previously disturbed strata 59
43. Diagram to show the effect of erosion upon a fault 60
44. A fault plane exhibiting drag 60
45. Map to show how a fault may be indicated by abrupt changes
in strike and dip 61
46. A series of parallel faults revealed by offsets 61
47. Field map prepared from the laboratory table 64
48. Areal geological map based upon the field map 64
49. A portion of the ruins of Messina 67
50. Ruins of the Carnegie Palace of Peace at Cartaga, Costa Rica 68
51. Overturned bowlders from Assam earthquake of 1897 69
52. Post sunk into ground during Charleston earthquake 69
53. Map showing localities where shocks have been reported at
sea off Cape Mendocino, California 70
54. Effect of seismic water wave in Japan 70
55. A fault of vertical displacement 71
56. Escarpment produced by an earthquake fault in India 72
57. A fault of lateral displacement 72
58. Fence parted and displaced by lateral displacement on fault
during California earthquake 72
59. Fault with vertical and lateral displacements combined 72
60. Diagram to show how small faults may be masked at the
earth’s surface 73
61. “Mole hill” effect above buried earthquake fault 73
62. Post-glacial earthquake faults 74
63. Earthquake cracks in Colorado desert 74
64. Railway tracks broken or buckled at time of earthquake 75
65. Railroad bridge in Japan damaged by earthquake 75
66. Diagrams to show contraction of earth’s crust during an
earthquake 76
67. Map of the Chedrang fault of India 76
68. Displacements along earthquake fault in Alaska 77
69. Abrupt change in direction of throw upon an earthquake fault 77
70. Map of faults in the Owens Valley, California, formed during
earthquake of 1872 78
71. Marquetry of the rock floor in the Tonopah district, Nevada 79
72. Map of Alaskan coast to show adjustments of level during an
earthquake 79
73. An Alaskan shore elevated seventeen feet during the
earthquake of 1899 80
74. Partially submerged forest from depression of shore in
Alaska during earthquake 80
75. Effect of settlement of the shore at Port Royal during
earthquake of 1907 80
76. Diagrams to illustrate the draining of lakes during
earthquakes 83
77. Diagram to illustrate the derangements of water flow during
an earthquake 84
78. Mud cones aligned upon an earthquake fissure in Servia 84
79. Craterlet formed near Charleston, South Carolina, during the
earthquake of 1886 85
80. Cross section of a craterlet 85
81. Map of the island of Ischia to show the concentration of
earthquake shocks 87
82. A line of earth fracture revealed in the plan of the relief 87
83. Seismotectonic lines of the West Indies 88
84. Device to illustrate the different effects of earthquakes in
firm rock and in loose materials 88
85. House wrecked in San Francisco earthquake 90
86. Building wrecked in California earthquake by roof and upper
floor battering down the upper walls 91
87. Breached volcanic cone in New Zealand showing the bending
down of the strata near the vent 96
88. View of the new Camiguin volcano formed in 1871 in the
Philippines 97
89. Map to show the belts of active volcanoes 98
90. A portion of the “fire girdle” of the Pacific 98
91. Volcanic cones formed in 1783 above the Skaptár fissure in
Iceland 99
92. Diagrams to illustrate the location of volcanic vents upon
fissure lines 100
93. Outline map showing the arrangement of volcanic vents upon
the island of Java 100
94. Map showing the migration of volcanoes along a fissure 101
95. Basaltic plateau of the northwestern United States due to
fissure eruptions of lava 102
96. Lava plains about the Snake River in Idaho 102
97. Characteristic profiles of lava volcanoes 103
98. A driblet cone 104
99. Leffingwell Crater, a cinder cone in the Owens Valley,
California 104
100. Map of Hawaii and its lava volcanoes 106
101. Section through Mauna Loa and Kilauea 106
102. Schematic diagram to illustrate the moving platform in the
crater of Kilauea 107
103. View of the open lava lake of Halemaumau 108
104. Map to show the manner of outflow of the lava from Kilauea
in the eruption of 1840 109
105. Lava of Matavanu flowing down to the sea during the eruption
of 1906 110
106. Lava stream discharging into the sea from a lava tunnel 111
107. Diagrammatic representation of the structure of lava
volcanoes as a result of the draining of frozen lava streams 112
108. Diagram to show the formation of mesas by outflow of lava in
valleys and subsequent erosion 112
109. Surface of lava of the Pahoehoe type 113
110. Three successive views to show the growth of the island of
Savaii, from lava outflow in 1906 113
111. View of the volcano of Stromboli showing the excentric
position of the crater 116
112. Diagrams to illustrate the eruptions within the crater of
Stromboli 117
113. Map of Volcano in the Æolian Islands 118
114. “Bread-crust” lava projectile from the eruption of Volcano
in 1888 119
115. “Cauliflower cloud” of steam and ash rising above the cinder
cone of Volcano 120
116. Eruption of Taal volcano in 1911 seen from a distance of six
miles 120
117. The thick mud veneer upon the island of Taal (after a
photograph by Deniston) 121
118. A pear-shaped lava projectile 121
119. Artificial production of a cinder cone 122
120. Diagram to show the contrast between a lava dome and a
cinder cone 123
121. Mayon volcano on the island of Luzon, Philippine Islands 123
122. A series of breached cinder cones due to migration of the
eruption along a fissure 124
123. The mouth upon the inner cone of Mount Vesuvius from which
flowed the lava of 1872 124
124. A row of parasitic cones raised above a fissure opened on
the flanks of Etna in 1892 125
125. View of Etna, showing the parasitic cones upon its flanks 125
126. Sketch map of Etna to show the areas covered by lava and
tuff respectively 126
127. Panum crater showing the caldera 126
128. View of Mount Vesuvius before the eruption of 1906 127
129. Sketches of the summit of the Vesuvian cone to bring out the
changes in its outline 128
130. Night view of Vesuvius from Naples before the outbreak of
1906, showing a small lava stream descending the central cone 129
131. Scoriaceous lava encroaching upon the tracks of the Vesuvian
railway 130
132. Map of Vesuvius, showing the position of the lava mouths
opened upon its flanks during the eruption of 1906 131
133. The ash curtain over Vesuvius lifting and disclosing the
outlines of the mountain 132
134. The central cone of Vesuvius as it appeared after the
eruption of 1906 132
135. A sunken road upon Vesuvius filled with indrifted ash 133
136. View of Vesuvius from the southwest during the waning stages
of the eruption 133
137. The main lava stream advancing upon Boscotrecase 133
138. A pine snapped off by the lava and carried forward upon its
surface 133
139. Lava front pushing over and running around a wall in its
path 134
140. One of the ruined villas in Boscotrecase 134
141. Three diagrams to illustrate the sequence of events during
the cone-building and crater-producing periods 135
142. The spine of Pelé rising above the chimney of the volcano
after the eruption of 1902 136
143. Successive outlines of the Pelé spine 137
144. Corrugated surface of the Vesuvian cone due to the mud flows
which followed the eruption of 1906 138
145. View of the Kammerbühl near Eger in Bohemia 139
146. Volcanic plug exposed by natural dissection of a volcanic
cone in Colorado 140
147. A dike cutting beds of tuff in a partly dissected volcano of
southwestern Colorado 140
148. Map and general view of St. Paul’s rocks, a volcanic cone
dissected by waves 141
149. Dissection by explosion of Little Bandai-san in 1888 141
150. The half-submerged volcano of Krakatoa before and after the
eruption of 1883 142
151. The cicatrice of the Banat 142
152. Diagram to illustrate a probable cause of formation of lava
reservoirs and the connection with volcanoes upon the surface 143
153. Effect of relief of load upon rocks by arching of a
competent formation 144
154. Character profiles connected with volcanoes 146
155. Diagrams to show the effect of decomposition in producing
spheroidal bowlders 150
156. Spheroidal weathering of an igneous rock 151
157. Dome structure in granite mass 152
158. Talus slope beneath a cliff 153
159. Striped ground from soil flow 154
160. Pavement of horizontal surface due to soil flow 154
161. Tree roots prying rock apart on fissure 154
162. Bowlder split by a growing tree 155
163. Rock mantle beneath soil and vegetable mat 155
164. Diagram to show the varying thickness of mantle rock upon
the different portions of a hill surface 156
165. Gullies from earliest stage of a river’s life 160
166. Partially dissected upland 160
167. Longitudinal sections of upper portion of a river valley 161
168. Map and sections of a stream meander 163
169. Tree undermined on the outer bank of a meander 164
170. Diagrams to show the successive positions of stream meanders 164
171. An ox-bow lake in the flood plain of a river 165
172. Schematic representation of a series of river terraces 165
173. “Bird-foot” delta of the Mississippi River 167
174. Diagrams to show the nature of delta deposits as exhibited
in sections 168
175. Gorge of the River Rhine near St. Goars 169
176. Valley with rounded shoulders characteristic of the stage of
adolescence 170
177. View of a maturely dissected upland 170
178. Hogarth’s line of beauty 171
179. View of the oldland of New England, with Mount Monadnock
rising in the distance 171
180. Comparison of the cross sections of river valleys of
different stages 172
181. The Beavertail Bend of the Yakima River 173
182. A rejuvenated river valley 174
183. Plan of a river narrows 174
184. Successive diagrams to illustrate the origin of “trellis
drainage” 175
185. Sketch maps to show the earlier and present drainage near
Harper’s Ferry 176
186. Section to illustrate the history of Snickers Gap 177
187. Character profiles of landscapes shaped by stream erosion in
humid climates 177
188. Diagram to show the seasonal range in the position of the
water table 180
189. Diagram to show the effect of an impervious layer upon the
descending water 181
190. Sketch map to illustrate corrosion of limestone along two
series of vertical joints 181
191. Diagram to show the relation of limestone caverns to the
river system of the district 182
192. Plan of a portion of Mammoth Cave, Kentucky 183
193. Trees and shrubs growing upon the bottoms of limestone sinks 183
194. Diagrams to show the manner of formation of stalactites and
stalagmites 185
195. Sinter formations in the Luray caverns 186
196. Map of the dolines of the Karst region 187
197. Cross section of a doline formed by inbreak 187
198. Sharp Karren of the Ifenplatte 188
199. The Zirknitz seasonal lake 189
200. Fissure springs arranged at intersections of rock fractures 190
201. Schematic diagrams to illustrate the different types of
artesian wells 191
202. Cross section of Geysir, Iceland 192
203. Apparatus for simulating geyser action 193
204. Cone of siliceous sinter about the Lone Star Geyser 194
205. Former shore lines in the Great Basin 198
206. Map of the former Lake Bonneville 199
207. Borax deposits in Death Valley, California 201
208. Hollowed forms of weathered granite in a desert of Central
Asia 201
209. Hollow hewn blocks in a wall in the Wadi Guerraui 202
210. Smooth granite domes shaped by exfoliation 203
211. Granite blocks rent by diffission 204
212. “Mushroom Rock” from a desert in Wyoming 205
213. Windkanten shaped by sand blast in the desert 205
214. The “stone lattice” of the desert 206
215. Shadow erosion in the desert 206
216. Cliffs in loess with characteristic vertical jointing 207
217. A cañon in loess worn by traffic and wind 207
218. Diagrams to illustrate the effects of obstructions in
arresting wind-driven sand 209
219. Sand accumulating on either side of a firm and impenetrable
obstruction 210
220. Successive diagrams to illustrate the history of the town of
Kunzen upon the Kurische Nehrung 210
221. View of desert barchans 211
222. Diagrams to show the relationships of dunes to sand supply
and wind direction 211
223. Ideal section showing the rising mountain wall about a
desert and the neighboring slope 212
224. Dry delta at the foot of a range upon the borders of a
desert 213
225. Map of distributaries of streams which issue at the western
base of the Sierra Nevadas 213
226. A group of “demoiselles” in the “bad lands” 214
227. Amphitheater at the head of the Wadi Beni Sur 215
228. Mesa and outlier in the Leucite Hills of Wyoming 216
229. Flat-bottomed basin separating dunes 216
230. Billowy surface of the salt crust on the central sink of the
desert of Lop 217
231. Schematic diagram to show the zones of deposition in their
order from the margin to the center of a desert 217
232. Mounds upon the site of the buried city of Nippur 218
233. Exhumed structures in the buried city of Nippur 218
234. Section across the High Plains 219
235. Section across the lenticular threads of alluvial deposits
of the High Plains 220
236. Distributaries of the foot hills superimposed upon an
earlier series 220
237. Character profiles in the landscapes of arid lands 220
238. Rain sculpturing under control by joints 224
239. Sagging of limestone above joints 224
240. Map of the joint-controlled Abisko Cañon in Northern Lapland 225
241. Map of the gorge of the Zambesi River below Victoria Falls 225
242. Controlled drainage network of the Shepaug River in
Connecticut 226
243. A river network of repeating rectangular pattern 226
244. Squared mountain masses which reveal a distribution of
joints in block patterns of different orders 228
245. Island groups of the Lofoten Archipelago 229
246. Diagrams to illustrate the composite profiles of the islands
on the Norwegian coast 229
247. Diagram to show the nature of the motions within a free
water wave 231
248. Diagram to illustrate the transformation of a free wave into
a breaker 232
249. Notched rock cliff and fallen blocks 233
250. A wave-cut chasm under control by joints 233
251. Grand Arch upon one of the Apostle Islands in Lake Superior 234
252. Stack near the shore of Lake Superior 234
253. The Marble Islands, stacks in a lake of the southern Andes 235
254. Squared stacks revealing the position of the joint planes on
which they were carved 235
255. Ideal section cut by waves upon a steep rocky shore 236
256. Map showing the outlines of the island of Heligoland at
different stages in its history 236
257. Ideal section carved by waves upon a steep shore of loose
materials 237
258. Sloping cliff and boulder pavement at Scituate,
Massachusetts 237
259. Map to show the nature of the shore current and the forms
which are molded by it 238
260. Crescent-shaped beach in the lee of a headland 239
261. Cross section of a beach pebble 239
262. A storm beach on the northeast shore of Green Bay 240
263. Spit of shingle on Au Train Island, Lake Superior 240
264. Barrier beach in front of a lagoon 241
265. Cross section of a barrier beach with lagoon in its rear 242
266. Cross section of a series of barriers and an outer bar 242
267. A barrier series and an outer bar on Lake Mendota at
Madison, Wisconsin 242
268. Series of barriers at the western end of Lake Superior 243
269. Character profiles resulting from wave action upon shores 243
270. The even shore line of a raised coast 246
271. The ragged coast line produced by subsidence 246
272. Portion of the Atlantic coastal plain at the base of the
oldland 246
273. Ideal form of cuestas and intermediate lowlands carved from
a coastal plain 247
274. Uplifted sea cave on the coast of California 248
275. Double-notched cliff near Cape Tiro, Celebes 248
276. Uplifted stacks on the coast of California 249
277. Uplifted shingle beach across the entrance to a former bay
upon the coast of California 250
278. Raised beach terraces near Elie, Fife, Scotland 250
279. Uplifted sea cliffs and terraces on the Alaskan coast 250
280. Diagrams to show how excessive sinking upon the sea floor
will cause the shore to migrate landward 251
281. A drowned river mouth or estuary upon a coastal plain 251
282. Archipelago of steep rocky islets due to submergence 252
283. The submerged Hudsonian channel which continues the Hudson
River across the continental shelf 252
284. Marine clay deposits near the mouths of the Maine rivers
which preserve a record of earlier subsidence and later
elevation 253
285. View of the three standing columns of the Temple of Jupiter
Serapis, at Pozzuoli 254
286. Three successive views to set forth the recent oscillations
of level on the northern shore of the Bay of Naples 255
287. Relief map of San Clemente Island, California 256
288. Relief map of Santa Catalina Island, California 257
289. Cross section of the Blue Grotto, on the island of Capri 258
290. Character profiles of coast elevation and subsidence 259
291. Map showing the distribution of existing glaciers and the
two important wind poles of the earth 263
292. An Alaskan glacier spreading out at the foot of the range
which nourishes it 264
293. Surface of a glacier whose upper layers spread with but
slight restraint from retaining walls 265
294. Section through a mountain glacier 267
295. Profile across the largest of the Icelandic ice caps 267
296. Ideal section across a continental glacier 267
297. View of the Eyriks Jökull, an ice cap of Iceland 268
298. The zones of the lower atmosphere as revealed by recent kite
and balloon exploration 269
299. Map of Greenland, showing the area of inland ice and the
routes of explorers 271
300. Profile in natural proportions across the southern end of
the continental glacier of Greenland 272
301. Map of a glacier tongue with dimple above 273
302. Edge of the Greenland inland ice, showing the nunataks
diminishing in size toward the interior 274
303. Moat surrounding a nunatak in Victoria Land 274
304. A glacier pavement of Permo-Carboniferous age in South
Africa 276
305. Diagrams to illustrate the manner of formation of scape
colks 277
306. Marginal moraine now forming at the edge of the continental
glacier of Greenland 279
307. Small lake between the ice front and a moraine which it has
recently built 279
308. View of a drained lake bottom between the ice front and an
abandoned moraine 280
309. Diagrams to show the manner of formation and the structure
of an outwash plain and fosse 280
310. Map of the ice masses of Victoria Land, Antarctica 282
311. Sections across the inland ice and the shelf ice of
Antarctica 283
312. Diagram to show the nature of the fixed glacial anticyclone
above continental glaciers 284
313. Snow deltas about the margins of a glacier tongue in
Greenland 285
314. View of the sea ice of the Arctic region 286
315. Map of the north polar regions, showing the area of drift
ice and the tracks of the _Jeannette_ and the _Fram_ 288
316. The shelf ice of Coats Land with surrounding pack ice 290
317. Tidewater cliff on a glacier tongue from which icebergs are
born 290
318. A Greenlandic iceberg after a long journey in warm latitudes 291
319. Diagram showing one way in which northern icebergs are born
from the glacier tongue 291
320. A northern iceberg surrounded by sea ice 292
321. Tabular Antarctic iceberg separating from the shelf ice 293
322. Map of the globe, showing the areas covered by continental
glaciers during the “ice age” 297
323. Glaciated granite bowlder weathered out of a moraine of
Permo-Carboniferous age, South Australia 298
324. Map to show the glaciated and nonglaciated regions of North
America 298
325. Map of the glaciated and nonglaciated areas of northern
Europe 299
326. An unstable erosion remnant characteristic of the “driftless
area” 300
327. Diagram showing the manner in which a continental glacier
obliterates existing valleys 301
328. Lake and marsh district in northern Wisconsin 302
329. Cross section in natural proportion of the latest North
American continental glacier 303
330. Diagram showing the earlier and the later glacier records
together upon the same limestone surface 304
331. Map to show the outcroppings of peculiar rock types in the
region of the Great Lakes, and some localities where “drift
copper” has been collected 305
332. Map of the “bowlder train” from Iron Hill, Rhode Island 306
333. Shapes and approximate natural sizes of some of the diamonds
from the Great Lakes region 307
334. Glacial map of a portion of the Great Lakes region 308
335. Section in coarse till 310
336. Sketch map of portions of Michigan, Ohio, and Indiana,
showing the distribution of moraines 312
337. Map of the vicinity of Devil’s Lake, Wisconsin, partly
covered by the continental glacier 313
338. Moraine with outwash apron in front 313
339. Fosse between an outwash plain and a moraine 314
340. View along an esker in southern Maine 315
341. Outline map of moraines and eskers in Finland 315
342. Sketch maps showing the relationships of drumlins and eskers 316
343. View of a drumlin, showing an opening in the till 317
344. Outline map of the front of the Green Bay lobe to show the
relationships of drumlins, moraines, outwash plains, and
ground moraine 317
345. Character profiles referable to continental glacier 318
346. View of the flood plain of the ancient Illinois River near
Peoria 320
347. Broadly terraced valleys which mark the floods that once
issued from the continental glacier of North America 321
348. Border drainage about the retreating ice front south of Lake
Erie 321
349. The “parallel roads” of Glen Roy in the Scottish Highlands 322
350. Map of Glen Roy and neighboring valleys of the Scottish
Highlands 322
351. Three successive diagrams to set forth the late glacial lake
history of the Scottish glens 324
352. Harvesting time on the fertile floor of the glacial Lake
Agassiz 325
353. Map of Lake Agassiz 325
354. Map showing some of the beaches of Lake Agassiz and its
outlet 326
355. Narrows of the Warren River where it passed between jaws of
granite and gneiss 327
356. Map of the valley of the Warren River near Minneapolis 327
357. Portion of the Herman beach on the shore of the former Lake
Agassiz 328
358. Map of the continental glacier of North America when it
covered the entire St. Lawrence basin 329
359. Outline map of the early Lake Maumee 330
360. Map to show the first stages of the ice-dammed lakes within
the St. Lawrence basin 330
361. Outline map of the later Lake Maumee and its outlet 332
362. Outline map of lakes Whittlesey and Saginaw 333
363. Map of the glacial Lake Warren 333
364. Map of the glacial Lake Algonquin 334
365. Outline map of the Nipissing Great Lakes 335
366. Probable preglacial drainage of the upper Ohio region 337
367. Diagrams to illustrate the episodes in the recent history of
a Connecticut river 338
368. The notched rock headland of Boyer Bluff on Lake Michigan 341
369. View of Mackinac Island from the direction of St. Ignace 342
370. The “Sugar Loaf”, a stack of Lake Algonquin upon Mackinac
Island 342
371. Beach ridges in series on Mackinac Island 343
372. Notched stack of the Nipissing Great Lakes at St. Ignace 343
373. Series of diagrams to illustrate the evolution of ideas
concerning the uplift of the lake region since the Ice Age 344
374. Map of the Great Lakes region to show the isobases and hinge
lines of uptilt 345
375. Series of diagrams to indicate the nature of the recovery of
the crust by uplift when unloaded of an ice mantle 346
376. Portion of the Inner Sandusky Bay, for comparison of the
shore line of 1820 with that of to-day 350
377. Ideal cross section of the Niagara Gorge to show the
marginal terrace 353
378. View of the bed of the Niagara River above the cataract
where water has been drained off 353
379. View of the Falls of St. Anthony in 1851 354
380. Ideal section to show the nature of the drilling process
beneath the cataract 355
381. Plan and section of the gorge, showing how the depth is
proportional to the width 355
382. Comparative views of the Canadian Falls in 1827 and 1895 356
383. Map to show the recession of the Canadian Fall 357
384. Comparison of the present with the future falls 358
385. Bird’s-eye view of the captured Canadian Fall at Wintergreen
Flats 358
386. Map of the Whirlpool Basin 360
387. Map of the cuestas which have played so important a part in
fixing the boundaries of the lake basins 361
388. Bird’s-eye view of the cuestas south of Lakes Ontario and
Erie 362
389. Sketch map of the greater portion of the Niagara Gorge to
illustrate Niagara history 363
390. Snowdrift hollowing its bed by nivation 368
391. Amphitheater formed upon a drift site in northern Lapland 369
392. The marginal crevasse on the highest margin of a glacier 370
393. Niches and cirques in the Bighorn Mountains of Wyoming 371
394. Subordinate cirques in the amphitheater on the west face of
the Wannehorn 371
395. “Biscuit cutting” effect of glacial sculpture in the Uinta
Mountains of Wyoming 372
396. Diagram to show the cause of the hyperbolic curve of cols 372
397. A col in the Selkirks 373
398. Diagrams to illustrate the formation of comb ridges, cols,
and horns 374
399. The U-shaped Kern Valley in the Sierra Nevadas of California 375
400. Glaciated valley wall, showing the sharp line which
separates the abraded from the undermined rock surface 375
401. View of the Vale of Chamonix from the séracs of the _Glacier
des Bossons_ 376
402. Map of an area near the continental divide in Colorado 377
403. Gorge of the Albula River in the Engadine cut through a rock
bar 378
404. Idealistic sketch, showing glaciated and nonglaciated side
valleys 378
405. Character profiles sculptured by mountain glaciers 379
406. Flat dome shaped under the margin of a Norwegian ice cap 379
407. Two views which illustrate successive stages in the shaping
of tinds 380
408. Schematic diagram to bring out the relationships of the
various types of mountain glaciers 383
409. Map of the Malaspina Glacier of Alaska 384
410. Map of the Baltoro Glacier of the Himalayas 385
411. View of the Triest Glacier, a hanging glacieret 385
412. Map of the Harriman Fjord Glacier of Alaska 386
413. Map of the Rotmoos Glacier, a radiating glacier of
Switzerland 386
414. Outline map of the Asulkan Glacier in the Selkirks, a
horseshoe glacier 387
415. Outline map of the Illecillewaet Glacier of the Selkirks, an
inherited-basin glacier 388
416. Diagram to illustrate the surface flow of glaciers 390
417. Diagram to show the transformation of crevasses into séracs 391
418. View of the _Glacier des Bossons_, showing the position of
accidents to Alpinists 392
419. Lines of flow upon the surface of the _Hintereisferner_
Glacier in the Alps 393
420. Lateral and medial moraines of the _Mer de Glace_ and its
tributaries 393
421. Ideal cross section of a mountain glacier 394
422. Diagrams to illustrate the melting effects upon glacier ice
of rock fragments of different sizes 394
423. Small glacier table upon the Great Aletsch Glacier 395
424. Effects of differential melting and subsequent refreezing
upon a glacier surface 396
425. Dirt cone with its casing in part removed 396
426. Schematic diagram to show the manner of formation of glacier
cornices 397
427. Superglacial stream upon the Great Aletsch Glacier 398
428. Ideal form of the surface left on the site of a piedmont
glacier apron 399
429. Map of the site of the earlier piedmont glacier of the Upper
Rhine 399
430. Diagram and map to bring out the characteristics of newland
lakes 402
431. View of the Warner Lakes, Oregon 402
432. Schematic diagram to illustrate the characteristics of
basin-range lakes 403
433. Schematic diagram of rift-valley lakes and the valley of the
Jordan 403
434. Map of the rift-valley lakes of East Central Africa 404
435. Earthquake lakes formed in 1811 in the flood plain of the
Lower Mississippi 404
436. View of a crater lake in Costa Rica 405
437. Diagrams to illustrate the characteristics of crater lakes 406
438. View of Snag Lake, a coulée lake in California 406
439. Diagrams to illustrate the characteristics of morainal lakes 407
440. Diagram to show the manner of formation of pit lakes 408
441. Diagrams to illustrate the characteristics of pit lakes 408
442. Diagram to show the manner of formation of glint lakes 409
443. Map of a series of glint lakes on the boundary of Sweden and
Norway 409
444. Map of ice-dam lakes near the Norwegian boundary of Sweden 410
445. Wave-cut terrace of a former ice-dam lake in Sweden 410
446. View of the Márjelen Lake from the summit of the Eggishorn 411
447. Diagrams to illustrate the arrangement and the characters of
rock-basin lakes 412
448. Convict Lake, a valley-moraine lake of California 413
449. Lake basins produced by successive slides from the steep
walls of a glaciated mountain valley 414
450. Lake Garda, a border lake upon the site of a piedmont apron 414
451. Diagrams to bring out the characteristics of ox-bow lakes 415
452. Diagrammatic section to illustrate the formation of
saucer-like basins between the levees of streams on a flood
plain 415
453. Saucer lakes upon the bed of the former river Warren 416
454. Levee lakes developed in series within meanders in a delta
plain 417
455. Raft lakes along the banks of the Red River in Arkansas and
Louisiana 418
456. Map of the Swiss lakes Thun and Brienz 419
457. Delta lakes formed at the mouth of the Mississippi 419
458. Delta lakes at the margin of the Nile delta 420
459. Diagrams to illustrate the characteristics of barrier lakes 420
460. Dune lakes on the coast of France 421
461. Sink lakes in Florida, with a schematic diagram to
illustrate the manner of their formation 421
462. Map of the Arve and the Upper Rhone 426
463. View of the Arve and the Rhone at their junction 427
464. A village in Switzerland built upon a strath at the head of
Lake Poschiavo 428
465. View of the floating bog and surrounding zones of vegetation
in a small glacial lake 429
466. Diagram to show how small lakes are transformed into peat
bogs 430
467. Map to show the anomalous position of the delta in Lake St.
Clair 431
468. A bowlder wall upon the shore of a small lake 432
469. Diagrams to show the effect of ice shove in producing ice
ramparts upon the shores of lakes 433
470. Various forms of ice ramparts 433
471. Map of Lake Mendota, showing the position of the ridge which
forms from ice expansion and the ice ramparts upon the shores 434
472. The great multiple mountain arc of Sewestan, British India 436
473. Diagrams to illustrate the theories of origin of mountain
arcs 437
474. Festoons of mountain arcs about the borders of the Pacific
Ocean 438
475. The interrupted Armorican Mountains common to western Europe
and eastern North America 438
476. A zone of diverse displacement in the western United States 439
477. Section of an East African block mountain 439
478. Tilted crust blocks in the Queantoweap valley 440
479. View of the laccolite of the Carriso Mountain 441
480. Map of laccolitic mountains 441
481. Ideal sections of laccolite and bysmalite 442
482. The gabled façade largely developed in desert landscapes 443
483. Balloon view of the Mythen in Switzerland 444
484. The battlement type of erosion mountain 445
485. Symmetrically formed low islands repeated in ranks upon
Temagami Lake, Ontario 445
486. Forms of crystals of a number of minerals 454
487. Forms of crystals of a number of minerals 457
488. A student’s contour map 469
489. Models to represent outcrops of rock 472
490. Special laboratory table set with a problem in geological
mapping which is solved in Figs. 47 and 48 472
491. Three field maps to be used as suggestions in arranging
laboratory table for problems in the preparation of areal
geological maps 473
492. Sketch map of Western Scotland and the Inner Hebrides to
show location of some points of special geological interest 481
493. Outline map of a geological pilgrimage across the continent
of Europe 483
EXPLANATORY LIST OF ABBREVIATIONS FOR JOURNAL NAMES IN READING
REFERENCES
Am. Geol.: American Geologist.
Am. Jour. Sci.: American Journal of Science, New Haven.
Ann. de Géogr.: Annales de Géographie, Paris.
Ann. Rept. Geol. and Geogr. Surv. Ter.: Annual Report of the
Geological and Geographical Survey of the Territories (Hayden),
Washington.
Ann. Rept. Geol. and Nat. Hist. Surv. Minn.: Annual Report of the
Geological and Natural History Survey of Minnesota, Minneapolis.
Ann. Rept. Mich. Geol. Surv.: Annual Report of the Michigan Geological
Survey, Lansing.
Ann. Rept. U. S. Geol. Surv.: Annual Report of the United States
Geological Survey, Washington.
Bull. Am. Geogr. Soc.: Bulletin of the American Geographical Society,
New York.
Bull. Earthq. Inv. Com. Japan: Bulletin of the Earthquake
Investigation Committee of Japan, Tokyo.
Bull. Geogr. Soc. Philadelphia: Bulletin of the Geographical Society
of Philadelphia.
Bull. Geol. Soc. Am.: Bulletin of the Geological Society of America.
Bull. Mus. Comp. Zoöl.: Bulletin of the Museum of Comparative Zoölogy,
Harvard College, Cambridge.
Bull. N. Y. State Mus.: Bulletin of the New York State Museum, Albany.
Bull. Soc. Belge d’Astronomie: Bulletin de la Société Belge
d’Astronomie, Brussels.
Bull. Soc. Belge Géol.: Bulletin de la Société Belge de Géologie,
Brussels.
Bull. Soc. Sc. Nat. Neuchâtel: Bulletin de la Société des Sciences
Naturelles de Neuchâtel.
Bull. Univ. Calif. Dept. Geol.: Bulletin of the University of
California, Department of Geology, Berkeley.
Bull. U. S. Geol. Surv.: Bulletin of the United States Geological
Survey, Washington.
Bull. Wis. Geol. and Nat. Hist. Surv.: Bulletin of the Wisconsin
Geological and Natural History Survey, Madison.
C. R. Cong. Géol. Intern.: Comptes Rendus de la Congrès Géologique
Internationale.
Dept. of Mines, Geol. Surv. Branch, Canada: Department of Mines,
Geological Survey Branch, Canada.
Geogr. Abh.: Geographische Abhandlungen.
Geogr. Jour.: Geographical Journal, London.
Geol. Folio U. S. Geol. Surv.: Geological Folio of the United States
Geological Survey.
Geol. Mag.: Geological Magazine, London (sections designated by
decades).
Jour. Am. Geogr. Soc.: Journal of the American Geographical Society,
New York.
Jour. Coll. Sci. Imp. Univ. Tokyo: Journal of the College of Science
of the Imperial University, Tokyo, Japan.
Jour. Geol.: Journal of Geology, Chicago.
Jour. Sch. Geogr.: Journal of School Geography.
Livret Guide Cong. Géol. Intern.: Livret Guide Congrès Géologique
Internationale.
Mem. Geol. Surv. India: Memoirs of the Geological Survey of India,
Calcutta.
Mitt. Geogr. Ges. Hamb.: Mitteilungen der Geographische Gesellschaft,
Hamburg.
Mon. U. S. Geol. Surv.: Monograph of the United States Geological
Survey, Washington.
Nat. Geogr. Mag.: National Geographic Magazine, Washington.
Nat. Geogr. Mon.: National Geographic Monographs, American Book
Company, New York.
Naturw. Wochenschr.: Naturwissenschaftliche Wochenschrift.
Pet. Mitt.: Petermanns Mittheilungen aus Justus Perthes’
Geographischer Anstalt, Gotha.
Pet. Mitt., Ergänzungsh. or Erg.: Petermanns Mittheilungen, Gotha
(Ergänzungsheft or Supplementary Paper).
Phil. Jour. Sci.: Philippine Journal of Science, Manila.
Phil. Trans.: Philosophical Transactions of the Royal Society, London.
Proc. Am. Acad. Arts and Sci.: Proceedings of the American Academy of
Arts and Sciences.
Proc. Am. Assoc. Adv. Sci.: Proceedings of the American Association
for the Advancement of Science.
Proc. Am. Phil. Soc.: Proceedings of the American Philosophical
Society, Philadelphia.
Proc. Bost. Soc. Nat. Hist.: Proceedings of the Boston Society of
Natural History, Boston.
Proc. Ind. Acad. Sci.: Proceedings of the Indiana Academy of Science.
Proc. Linn. Soc. New South Wales: Proceedings of the Linnean Society
of New South Wales.
Proc. Ohio State Acad. Sci.: Proceedings of the Ohio State Academy of
Science.
Prof. Pap. U. S. Geol. Surv.: Professional Paper of the United States
Geological Survey, Washington.
Pub. Carneg. Inst.: Publication of the Carnegie Institution of
Washington.
Pub. Mich. Geol. and Biol. Surv.: Publication of the Michigan
Geological and Biological Survey, Lansing.
Quart. Jour. Geol. Soc. Lond.: Quarterly Journal of the Geological
Society, London.
Rept. Brit. Assoc. Adv. Sci.: Report of the British Association for
the Advancement of Science.
Rept. Geol. Surv. Mich.: Report of the Geological Survey of Michigan,
Lansing.
Rept. Mich. Acad. Sci.: Report of the Michigan Academy of Science,
Lansing.
Rept. Nat. Conserv. Com.: Report of the National Conservation
Commission, Washington.
Rept. Smithson. Inst.: Report of the Smithsonian Institution,
Washington.
Sci. Bull. Brooklyn Inst. Arts and Sci.: Science Bulletin of the
Brooklyn Institute of Arts and Sciences.
Scot. Geogr. Mag.: Scottish Geographic Magazine, Edinburgh.
Smith. Cont. to Knowl.: Smithsonian Contributions to Knowledge,
Washington.
Tech. Quart.: Technology Quarterly of the Massachusetts Institute of
Technology, Boston.
Trans. Am. Inst. Min. Eng.: Transactions of the American Institute of
Mining Engineers, New York.
Trans. Roy. Dublin Soc.: Transactions of the Royal Dublin Society.
Trans. Seis. Soc. Japan: Transactions of the Seismological Society of
Japan, Tokyo.
Trans. Wis. Acad. Sci.: Transactions of the Wisconsin Academy of
Sciences, Arts, and Letters, Madison.
U. S. Geogr. and Geol. Surv. Rocky Mt. Region: United States
Geographical and Geological Survey of the Rocky Mountain Region
(Powell), Washington.
Zeit. d. Gesell. f. Erdk. z. Berlin: Zeitschrift der Gesellschaft für
Erdkunde zu Berlin.
Zeit. f. Gletscherk: Zeitschrift für Gletscherkunde, Berlin.
EARTH FEATURES AND THEIR MEANING
CHAPTER I
THE COMPILATION OF EARTH HISTORY
=The sources of the history.=—The science which deals with the
chapters of earth history that antedate the earliest human writings
is geology. The pages of the record are the layers of rock which make
up the outer shell of our world. Here as in old manuscripts pages are
sometimes found to be missing, and on others the writing is largely
effaced so as to be indistinct or even illegible. An intelligent
interpretation of this record requires a knowledge of the materials
and the structure of the earth, as well as a proper conception of the
agencies which have caused change and so developed the history. These
agencies in operation are physical and chemical processes, and so the
sciences of physics and chemistry are fundamental in any extended study
of geology. Not only is geology, so to speak, founded upon chemistry
and physics, but its field overlaps that of many other important
sciences. The earliest earth history has to do with the form, size, and
physical condition of a minor planet in the solar system. The earliest
portion of the story belongs therefore to astronomy, and no sharp line
can be drawn to separate this chapter from those later ones which are
more clearly within the domain of geology.
=Subdivisions of geology.=—The terms “cosmic geology” and “astronomic
geology” have sometimes been used to cover the astronomy of the earth
planet. The later earth history develops, among other things, the
varied forms of animal and vegetable life which have had a definite
order of appearance. Their study is to a large extent zoölogy and
botany, though here considered from an essentially different viewpoint.
This subdivision of our science is called paleontological geology or
paleontology, which in common usage includes the plant as well as the
animal world, or what is sometimes called paleobotany. In order to fix
the order of events in geological history, these biological studies
are necessary, for the pages of the record have many of them been
misplaced as a result of the vicissitudes of earth history, and the
remains of life in the rock layers supply a pagination from which it is
possible to correctly rearrange the misplaced pages. As compiled into a
consecutive history of the earth since life appeared upon it, we have
the division of historical geology; though this differs but little from
stratigraphical geology, the emphasis in the case of the former being
placed on the history itself and in the latter upon the arrangement of
events—the pagination of the record.
So far as they are known to us, the materials of which the earth is
composed are minerals grouped into various characteristic aggregates
known as rocks. Here the science is founded upon mineralogy as well as
chemistry, and a study of the rock materials of the earth is designated
petrographical geology or petrography. The various rocks which enter
into the composition of the earth’s outer shell—the only portion known
to us from direct observation—are built into it in an architecture
which, when carefully studied, discloses important events in the
earth’s history. The division of the science which is concerned with
earth architecture is geotectonic or structural geology.
=The study of earth features and their significance.=—The features
upon the surface of the earth have all their deep significance, and
if properly understood, a flood of light is thrown, not only upon
present conditions, but upon many chapters of the earth’s earlier
history. Here the relation of our study to topography and geography is
very close, so that the lines of separation are but ill defined. The
terms “physiographical geology”, “physiography”, and “geomorphology”
are concerned with the configuration of the earth’s surface—its
physiognomy—and with the genesis of its individual surface features.
It is this genetical side of physiography which separates it from
topography and lends it an absorbing interest, though it causes it
to largely overlap the division of dynamical geology or the study of
geological processes. In fact, the difference between dynamical geology
and physiography is largely one of emphasis, the stress being laid
upon the processes in the former and upon the resultant features in the
latter.
Under dynamical geology are included important subdivisions, such
as seismic geology, or the study of earthquakes, and vulcanology,
or the study of volcanoes. Another large subject, glacial geology,
belongs within the broad frontier common to both dynamical geology
and physiography. A relatively new subdivision of geological science
is orientational geology, which is concerned with the trend of earth
features, and is closely related both to physiography and to dynamical
and structural geology.
=Tabular recapitulation.=—In a slightly different arrangement from the
above order of mention, the subdivisions of geology are as follows:—
_Subdivisions of Geology_
_Petrographical Geology._ Materials of the earth.
_Geotectonic Geology._ Architecture of the earth’s
outer shell.
_Dynamical Geology._ Earth processes.
Seismic Geology—earthquakes.
Vulcanology—volcanoes. Glacial
Geology—glaciers, etc.
_Physiographical Geology._ Earth physiognomy and its
genesis.
_Orientational Geology._ The arrangement and the trend
of earth features.
In one way or another all of the above subdivisions of geology are in
some way concerned in the genesis of earth physiognomy, and they must
therefore be given consideration in a work which is devoted to a study
of the meaning of earth features. The compiled record of the rocks is,
however, something quite apart and without pertinence to the present
work. As already indicated its subdivisions are:—
_Astronomic Geology._ Planetary history of the earth.
_Statigraphic Geology._ The pagination of earth records.
_Historical Geology._ The compiled record and its
interpretation.
_Paleontological Geology._ The evolution of life upon the earth.
In every attempt at systematic arrangement difficulties are
encountered, usually because no one consideration can be used
throughout as the basis of classification. Such terms as “economic
geology” and “mining geology” have either a pedagogical or a commercial
significance, and so would hardly fit into the system which we have
outlined.
=Geological processes not universal.=—It is inevitable that the
geology of regions which are easily accessible for study should
have absorbed the larger measure of attention; but it should not be
forgotten that geology is concerned with the history of the entire
world, and that perspective will be lost and erroneous conclusions
drawn if local conditions are kept too often before the eyes. To
illustrate by a single instance, the best studied regions of the globe
are those in which fairly abundant precipitation in the form of rain
has fitted the land for easy conditions of life, and has thus permitted
the development of a high civilization. In degree, and to some extent
also in kind, geologic processes are markedly different within those
widely extended regions which, because either arid or cold, have been
but ill fitted for human habitation. Yet in the historical development
of the earth, those geologic processes which obtain in desert or
polar regions are none the less important because less often and less
carefully observed.
=Change, and not stability, the order of nature.=—Man is ever prone to
emphasize the importance of apparent facts to the disadvantage of those
less clearly revealed though equally potent. The ancient notion of the
_terra firma_, the safe and solid ground, arose because of its contrast
with the far more mobile bodies of water; but this illusion is quickly
dispelled with the sudden quaking of the ground. Experience has clearly
shown that, both upon and beneath the earth’s surface, chemical and
physical changes are going on, subject to but little interruption. “The
hills rock-ribbed and ancient as the sun” is a poetical metaphor; for
the Himalayas, the loftiest mountains upon the globe, were, to speak
in geological terms, raised from the sea but yesterday. Even to-day
they are pushing up their heads, only to be relentlessly planed down
through the action of the atmosphere, of ice, and of running water.
Even more than has generally been supposed, the earth suffers change.
Often within the space of a few seconds, to the accompaniment of a
heavy earthquake, many square miles of territory are bodily uplifted,
while neighboring areas may be relatively depressed. Thus change, and
not stability, is the order of nature.
=Observational geology _versus_ speculative philosophy.=—There appears
to be a more or less prevalent notion that the views which are held
by scientists in one generation are abandoned by those of the next;
and this is apt to lead to the belief that little is really known and
that much is largely guessed. Some ground there undoubtedly is for
such skepticism, though much of it may be accounted for by a general
failure among scientists, as well as others, to clearly differentiate
that which is essentially speculative from what is based broadly upon
observed facts. Even with extended observation, the possibility of
explaining the facts in more than one way is not excluded; but the
line is nevertheless a broad one which separates this entire field
of observation from what is essentially speculative philosophy. To
illustrate: the mechanics of the action which goes on within volcanic
craters is now fairly well understood as a result of many and extended
observations, and it is little likely that future generations of
geologists will discredit the main conclusions which have been reached.
The cause of the rise of the lava to the earth’s surface is, on the
other hand, much less clearly demonstrated, and the views which are
held express rather the differing opinions than any clear deductions
from observation. Again, and similarly, the physical history of the
great continental glaciers of the so-called “ice age” is far more
thoroughly known than that of any existing glacier of the same type;
but the cause of the climatic changes which brought on the glaciation
is still largely a matter for speculation.
In the present work, the attempt will be, so far as possible, to give
an exposition of geologic processes and the earth features which result
from them, with hints only at those ultimate causes which lie hidden in
the background.
=The scientific attitude and temper.=—The student of science should
make it his aim, not only clearly to separate in his studies the
proximate from the ultimate causes of observed phenomena, but he should
keep his mind always open for reaching individual conclusions. No
doctrines should be accepted finally upon faith merely, but subject
rather to his own reasoning processes. This should not be interpreted
to mean that concerning matters of which he knows little or nothing
he should not pay respect to the recognized authorities; but his
acceptance of any theory should be subject to review so soon as his
own horizon has been sufficiently enlarged. False theories could hardly
have endured so long in the past, had not too great respect been given
to authorities, and individual reasoning processes been held too long
in subjection.
=The value of the hypothesis.=—Because all the facts necessary for a
full interpretation of observed phenomena are not at one’s hand, this
should not be made to stand in the way of provisional explanations. If
science is to advance, the use of hypothesis is absolutely essential;
but the particular hypothesis adopted should be regarded as temporary
and as indicating a line of observation or of experimentation which
is to be followed in testing it. Thus regarded with an open mind,
inadequate hypotheses are eventually found to be untenable, whereas
correct explanations of the facts by the same process are confirmed.
Most hypotheses of science are but partially correct, for we now “see
through a glass darkly”; but even so, if properly tested, the false
elements in the hypothesis are one after the other eliminated as the
embodied truth is confirmed and enlarged. Thus “working hypothesis”
passes into theory and becomes an integral part of science.
READING REFERENCES FOR CHAPTER I
The most comprehensive of general geological texts written in English
is Chamberlin and Salisbury’s “Geology” in three volumes (Henry Holt,
1904-1906), the first volume of which is devoted exclusively to
geological processes and their results. An abridged one-volume edition
of the work intended for use as a college text was issued in 1906
(College Geology, Henry Holt). Other standard texts are:—
SIR ARCHIBALD GEIKIE. Text-book of Geology, 4th ed. 2 vols. London,
1902, pp. 1472.
W. B. SCOTT. An Introduction to Geology. 2d ed. Macmillan, 1907, pp.
816.
J. D. DANA. Manual of Geology. New edition. American Book Company,
1895, pp. 1087.
JOSEPH LECONTE. Elements of Geology. (Revised by Fairchild.) Appleton,
1905, pp. 667.
A very valuable guide to the recent literature of dynamical and
structural geology is Branner’s “Syllabus of a Course of Lectures on
Elementary Geology” (Stanford University, 1908).
On the relation of geology to landscape, a number of interesting books
have been written:—
JAMES GEIKIE. Earth Sculpture or the Origin of Land-Forms. New York
and London, 1896, pp. 397.
JOHN E. MARR. The Scientific Study of Scenery. Methuen, London, 1900,
pp. 368.
SIR A. GEIKIE. The Scenery of Scotland. 3d ed. Macmillan, London,
1901, pp. 540.
SIR JOHN LUBBOCK. The Scenery of Switzerland and the Causes to which
it is Due. Macmillan, London, 1896, pp. 480.
LORD AVEBURY. The Scenery of England. Macmillan, London, 1902, pp. 534.
SIR A. GEIKIE. Landscape in History, and Other Essays. Macmillan,
London, 1905, pp. 352.
N. S. SHALER. Aspects of the Earth. Scribners, New York, 1889, pp. 344.
G. DE LA NOE ET EMM. DE MARGERIE. Les Formes du Terrain, Service
Géographique de l’Armée. Paris, 1888, pp. 205, pls. 48.
W. M. DAVIS. Practical Exercises in Physical Geography, with
Accompanying Atlas. Ginn and Co., Boston, 1908, pp. 148, pls. 45.
JOHN MUIR. The Mountains of California. Unwin, London, 1894, pp. 381.
Upon the use and interpretation of topographic maps in illustration of
characteristic earth features, the following are recommended:—
R. D. SALISBURY and W. W. ATWOOD. The Interpretation of Topographic
Maps, Prof. Pap., 60 U.S. Geol. Surv., pp. 84, pls. 170.
D. W. JOHNSON and F. E. MATTHES. The Relation of Geology to
Topography, in Breed and Hosmer’s Principles and Practice of
Surveying, vol. 2. Wiley, New York, 1908.
GÉNÉRAL BERTHAUT. Topologie, Étude du Terrain, Service Géographique de
l’Armée. Paris, 1909, 2 vols., pp. 330 and 674, pls. 265.
The United States Geological Survey issues free of charge a list of
100 topographic atlas sheets which illustrate the more important
physiographic types. In his “Traité de Géographie Physique”, Professor
E. de Martonne has given at the end of each chapter the important
foreign maps which illustrate the physiographic types there described.
“The Principles of Geology”, by Sir Charles Lyell, published first in
three volumes, appeared in the years 1830-1833, and may be said to
mark the beginning of modern geology. Later reduced to two volumes, an
eleventh edition of the work was issued in 1872 (Appleton) and may be
profitably read and studied to-day by all students of geology. Those
familiar with the German language will derive both pleasure and profit
from a perusal of Neumayr’s “Erdgeschichte” (2d ed. revised by Uhlig.
Leipzig and Vienna, 2 vols., 1895-1897), and especially the first
volume, “Allgemeine Geologie.” A recent French work to be recommended
is Haug’s “Traité de Géologie” (Paris, 1907).
Some texts of physical geography may well be consulted, especially Emm.
de Martonne’s “Traité de Géographie Physique.” Colin, Paris, 1909, pp.
910, pls. 48, and figs. 396.
* * * * *
NOTE. An explanatory list of abbreviations used in the reading
references follows the List of Illustrations.