THE NATIONAL GEOGRAPHIC MAGAZINE
VOLUME I, 1889
WASHINGTON
PUBLISHED BY THE NATIONAL GEOGRAPHIC SOCIETY
1889
OFFICERS OF THE NATIONAL GEOGRAPHIC SOCIETY
1889
GARDINER G. HUBBARD, _President_
HERBERT G. OGDEN |
GEO. L. DYER |
A. W. GREELY | _Vice-Presidents_
C. HART MERRIAM |
A. H. THOMPSON |
CHARLES J. BELL, _Treasurer_
HENRY GANNETT |
GEORGE KENNAN | _Secretaries_
CLEVELAND ABBE |
MARCUS BAKER |
ROGERS BIRNIE, JR. |
G. BROWN GOODE |
C. A. KENASTON | _Managers_
W. B. POWELL |
O. H. TITTMANN |
JAMES C. WELLING |
PRINTERS
TUTTLE, MOREHOUSE & TAYLOR,
NEW HAVEN CONN.
Vol. I. No. 1.
THE NATIONAL GEOGRAPHIC MAGAZINE.
PUBLISHED BY THE
NATIONAL GEOGRAPHIC SOCIETY.
WASHINGTON, D. C.
Price 50 Cents.
CONTENTS.
Announcement
Introductory Address by the President
Geographic Methods in Geologic Investigation: Wm. M. Davis
The Classification of Geographic Forms by Genesis: W. J. McGee
The Great Storm of March 11 to 14, 1888: A. W. Greely,
Everett Hayden
The Survey of the Coast: Herbert G. Ogden
The Survey and Map of Massachusetts: Henry Gannett
Proceedings of the National Geographic Society
National Geographic Society
Certificate of incorporation
By-laws
List of Officers, 1888
List of Members
PRESS OF TUTTLE, MOREHOUSE & TAYLOR, NEW HAVEN, CONN.
ANNOUNCEMENT.
The "NATIONAL GEOGRAPHIC SOCIETY" has been organized "to increase and
diffuse geographic knowledge," and the publication of a Magazine has
been determined upon as one means of accomplishing these purposes.
It will contain memoirs, essays, notes, correspondence, reviews, etc.,
relating to Geographic matters. As it is not intended to be simply the
organ of the Society, its pages will be open to all persons interested
in Geography, in the hope that it may become a channel of
intercommunication, stimulate geographic investigation and prove an
acceptable medium for the publication of results.
The Magazine is to be edited by the Society. At present it will be
issued at irregular intervals, but as the sources of information are
increased the numbers will appear periodically.
The National Capital seems to be the natural and appropriate place for
an association of this character, and the aim of the founders has been,
therefore, to form a National rather than a local society.
As it is hoped to diffuse as well as to increase knowledge, due
prominence will be given to the educational aspect of geographic
matters, and efforts will be made to stimulate an interest in original
sources of information.
In addition to organizing, holding regular fortnightly meetings for
presenting scientific and popular communications, and entering upon the
publication of a Magazine, considerable progress has been made in the
preparation of a Physical Atlas of the United States.
The Society was organized in January, 1888, under the laws of the
District of Columbia, and has at present an active membership of about
two hundred persons. But there is no limitation to the number of
members, and it will welcome both leaders and followers in geographic
science, in order to better accomplish the objects of its organization.
October, 1888.
Correspondence with the Society should be addressed to Mr. GEORGE
KENNAN, Corresponding Secretary, No. 1318 Massachusetts Avenue,
Washington, D. C.
THE NATIONAL GEOGRAPHIC MAGAZINE.
Vol. I. 1888. No. 1.
INTRODUCTORY ADDRESS.
BY THE PRESIDENT, MR. GARDINER G. HUBBARD.
I am not a scientific man, nor can I lay claim to any special knowledge
that would entitle me to be called a "Geographer." I owe the honor of
my election as President of the National Geographic Society simply to
the fact that I am one of those who desire to further the prosecution
of geographic research. I possess only the same general interest in the
subject of geography that should be felt by every educated man.
By my election you notify the public that the membership of our Society
will not be confined to professional geographers, but will include that
large number who, like myself, desire to promote special researches by
others, and to diffuse the knowledge so gained, among men, so that we
may all know more of the world upon which we live.
By the establishment of this Society we hope to bring together (1) the
scattered workers of our country, and (2) the persons who desire to
promote their researches. In union there is strength, and through the
medium of a national organization, we may hope to promote geographic
research in a manner that could not be accomplished by scattered
individuals, or by local societies; we may also hope--through the same
agency--to diffuse the results of geographic research over a wider area
than would otherwise be possible.
The position to which I have been called has compelled me to become a
student. Since my election I have been trying to learn the meaning of
the word "geography," and something of the history of the science to
which it relates. The Greek origin of the word ([Greek: gê], the earth,
and [Greek: graphê], description) betrays the source from which we
derived the science, and shows that it relates to a description of the
earth. But the "earth" known to the Greeks was a very different thing
from the earth with which we are acquainted.
To the ancient Greek it meant land--not all land, but only a limited
territory, in the centre of which he lived. His earth comprised simply
the Persian Empire, Italy, Egypt and the borders of the Black and
Mediterranean seas, besides his own country. Beyond these limits, the
land extended indefinitely to an unknown distance--till it reached the
borders of the great ocean which completely surrounded it.
To the members of this society the word "earth" suggests a very
different idea. The term arouses in our minds the conception of an
enormous globe suspended in empty space, one side in shadow and the
other bathed in the rays of the sun. The outer surface of this globe
consists of a uniform, unbroken ocean of air, enclosing another more
solid surface (composed partly of land and partly of water), which
teems with countless forms of animal and vegetable life. This is the
earth of which geography gives _us_ a description.
To the ancients the earth was a flat plain, solid and immovable, and
surrounded by water, out of which the sun rose in the east and into
which it set in the west. To them "Geography" meant simply a
description of the lands with which they were acquainted.
Herodotus, who lived about the year 450 B.C., transmitted to posterity
an account of the world as it was known in his day. We look upon him as
the father of geography as well as of history. He visited the known
regions of the earth, and described accurately what he saw, thus laying
the foundations of comparative geography.
About 300 years B.C., Alexander the Great penetrated into hitherto
unknown regions, conquered India and Russia, and founded the Macedonian
Empire. He sent a naval expedition to explore the coasts of India,
accompanied by philosophers or learned men, who described the new
countries discovered and the character of their inhabitants. This
voyage may be considered as originating the science of Political
Geography, or the geography of man.
About the year 200 B.C., Eratosthenes of Cyrene, the keeper of the
Royal Library at Alexandria, became convinced, from experiments, that
the idea of the rotundity of the earth, which had been advanced by some
of his predecessors, was correct, and attempted to determine upon
correct principles its magnitude. The town of Cyrene, on the river
Nile, was situated exactly under the tropic, for he knew that on the
day of the summer solstice, the sun's rays illuminated at noon the
bottom of a deep well in that city. At Alexandria, however, on the day
of the summer solstice, Eratosthenes observed that the vertical finger
of a sun-dial cast a shadow at noon, showing that the sun was not there
exactly overhead. From the length of the shadow he ascertained the
sun's distance from the zenith to be 7° 12', or one-fiftieth part of
the circumference of the heavens; from which he calculated that if the
world was round the distance between Alexandria and Cyrene should be
one-fiftieth part of the circumference of the world. The distance
between these cities was 5000 stadia, from which he calculated that the
circumference of the world was fifty times this amount, or 250,000
stadia. Unfortunately we are ignorant of the exact length of a stadium,
so we have no means of testing the accuracy of his deduction. He was
the founder of Mathematical Geography; it became possible through the
labors of Eratosthenes to determine the location of places on the
surface of the earth by means of lines corresponding to our lines of
latitude and longitude.
Claudius Ptolemy, in the second century of the Christian era, made a
catalogue of the positions of plans as determined by Eratosthenes and
his successors, and with this as his basis, he made a series of
twenty-six maps, thus exhibiting, at a glance, in geographical form,
the results of the labors of all who preceded him. To him we owe the
art of map-making, the origination of Geographic Art.
We thus see that when Rome began to rule the world, the Greeks had made
great progress in geography. They already possessed Comparative,
Political and Mathematical Geography, and Geographic Art, or the art of
making maps.
Then came a pause in the progress of geography.
The Romans were so constantly occupied with the practical affairs of
life, that they paid little attention to any other kind of geography
than that which facilitated the administration of their empire. They
were great road-builders, and laid out highways from Rome to the
farthest limits of their possessions. Maps of their military roads were
made, but little else. These exhibited with accuracy the less and
greater stations on the route from Rome to India, and from Rome to the
further end of Britain.
Then came the decline and fall of Rome, and with it the complete
collapse of geographical knowledge. In the dark ages, geography
practically ceased to exist. In the typical map of the middle ages,
Jerusalem lay in the centre with Paradise on the East and Europe on the
West. It was not until the close of the dark ages that the spirit of
discovery was re-awakened. Then the adventurous Northmen from Norway
and Sweden crossed the ocean to Iceland.
From Iceland they proceeded to Greenland and even visited the main-land
of North America about the year 1000 A.D., coasting as far south as New
England; but these voyages led to no practical results, and were
forgotten or looked upon as myths, until within a few years. For
hundreds of years geography made but little advance--and the
discoveries of five centuries were less than those now made in five
years. In the fourteenth or fifteenth century, the mariner's compass
was introduced into Europe from China, and it then became possible to
venture upon the ocean far out of sight of land. Columbus instead of
coasting from shore to shore like the ancient Northmen, boldly set sail
across the Atlantic. To many of his contemporaries it must have seemed
madness to seek the East by thus sailing towards the West, and we need
hardly wonder at the opposition experienced from his crew. The
rotundity of the earth had become to him an objective reality, and in
sublime faith he pursued his westward way. Expecting to find the East
Indies he found America instead. Five centuries had elapsed since the
Northmen had made their voyages to these shores--and their labors had
proved to be barren of results. The discovery of Columbus, however,
immediately bore fruit. It was his genius and perseverance alone that
gave the new world to the people of Europe, and he is therefore
rightfully entitled to be called the discoverer of America. His
discovery was fraught with enormous consequences, and it inaugurated a
new era for geographic research. The spirit of discovery was quickened
and geographic knowledge advanced with a great leap. America was
explored; Africa was circumnavigated. Magellan demonstrated the
rotundity of the earth by sailing westward until he reached his
starting point. Everywhere--all over the civilized world--the spirit of
adventure was aroused. Navigators from England, Holland, France and
Spain rapidly extended the boundaries of geographical knowledge, while
explorers penetrated into the interior of the new lands discovered. The
mighty impetus given by Columbus set the whole world in motion and it
has gone on moving ever since with accelerated velocity.
The great progress that has been made can hardly be realized without
comparing the famous Borgia map, constructed about one hundred years
before the discovery of America, with the modern maps of the same
countries; or Hubbard's map of New England made two hundred years ago,
with the corresponding map of to-day. The improvements in map-making
originated with Mercator, who, in 1556 constructed his cylindrical
projection of the sphere. But it has been only during the last hundred
years that great progress has been made. Much yet remains to be done
before geographic art can fully accomplish its mission.
The present century forms a new era in the progress of geography--the
era of organized research. In 1830, the Royal Geographical Society of
England was founded, and it already forms a landmark in the history of
discovery. The Paris Society preceded it in point of time, and the
other countries of Europe soon followed the example. Through these
organizations, students and explorers have been encouraged and
assisted, and information systematically collected and arranged. The
wide diffusion of geographical knowledge through the medium of these
societies and the publicity of the discussions and criticism that
followed, operated to direct the current of exploration into the most
useful channels. Before organized effort, darkness gave way at every
step. Each observer added fresh knowledge to the existing store,
without unnecessary duplication of research. The reports of discoveries
were discussed and criticized by the societies, and the contributions
of all were co-ordinated into one great whole.
America refuses to be left in the rear. Already her explorers are in
every land and on every sea. Already she has contributed her quota of
martyrs in the frozen north, and has led the way into the torrid
regions of Africa. The people of Europe, through Columbus, opened up a
new world for us; and we, through Stanley, have discovered a new world
in the old, for them.
Much has been done on land--little on the other three-quarters of the
earth's surface. But here America has laid the foundations of a new
science,--the Geography of the Sea.
Our explorers have mapped out the surface of the ocean and discovered
the great movements of the waters. They have traced the southward flow
of the Arctic waters to temper the climate of the torrid zone. They
have followed the northward set of the heated waters of the equator and
have shown how they form those wonderful rivers of warm water that
flow, without walls, through the colder waters of the sea, till they
strike the western shores of Europe and America, and how they render
habitable the almost Arctic countries of Great Britain and Alaska. They
have even followed these warm currents further and shown how they
penetrate the Arctic Ocean to lessen the rigors of the Arctic cold.
Bravely, but vainly, have they sought for that _ignis fatuus_ of
explorers--the open polar sea--produced by the action of the warm
waters from the south.
American explorers have sounded the depths of the ocean and discovered
mountains and valleys beneath the waves. They have found the great
plateaus on which the cables rest that bring us into instantaneous
communication with the rest of the world. They have shown the probable
existence of a vast submarine range of mountains, extending nearly the
whole length of the Pacific Ocean--mountains so high that their summits
rise above the surface to form islands and archipelagoes in the
Pacific. And all this vast region of the earth, which, a few years ago,
was considered uninhabitable on account of the great pressure, they
have discovered to be teeming with life. From the depths of the ocean
they have brought living things, whose lives were spent under
conditions of such pressure that the elastic force of their own bodies
burst them open before they could be brought to the surface; living
creatures whose self-luminous spots supplied them with the light denied
them in the deep abyss from which they sprang--abysses so deep that the
powerful rays of the sun could only feebly penetrate to illuminate or
warm.
The exploring vessels of our Fish Commission have discovered in the
deep sea, in one single season, more forms of life than were found by
the Challenger Expedition in a three years' cruise. Through their
agency, we have studied the geographical distribution of marine life;
and in our marine laboratories, explorers have studied the life history
of the most useful forms.
The knowledge gained has enabled us to breed and multiply at will; to
protect the young fish during the period of their infancy--when alone
they are liable to wholesale destruction--finally to release them in
the ocean, in those waters that are most suitable to their growth. The
fecundity of fish is so great, and the protection afforded them during
the critical period of their life so ample, that it may now be possible
to feed the world from the ocean and set the laws of Matthews at
defiance. Our geographers of the sea have shown that an acre of water
may be made to produce more food for the support of man than ten acres
of arable land. They have thrown open to cultivation a territory of the
earth constituting three-quarters of the entire surface of the globe.
And what shall we say of our conquests in that other vast territory of
the earth, greater in extent than all the oceans and the lands put
together--the atmosphere that surrounds it.
Here again America has led the way, and laid the foundations of a
Geography of the Air. But a little while ago and we might have truly
said with the ancients "the wind bloweth where it listeth, and we know
neither from whence it comes nor whither it goes"; but now our
explorers track the wind from point to point and telegraph warnings in
advance of the storm.
In this department, the Geography of the Air, we have far outstripped
the nations of the world. We have passed the mob-period of research
when the observations of multitudes of individuals amounted to little,
from lack of concentrated action. Organization has been effected. A
Central Bureau has been established in Washington, and an army of
trained observers has been dispersed over the surface of the globe, who
all observe the condition of the atmosphere according to a
pre-concerted plan.
The vessels of our navy and the mercantile marine of our own and other
countries have been impressed into the service, and thus our
geographers of the air are stationed in every land and traverse the
waters of every sea. Every day, at the same moment of absolute time,
they observe and note the condition of the atmosphere at the part of
the earth where they happen to be, and the latitude and longitude of
their position. The collocation of these observations gives us a series
of what may be termed instantaneous photographs of the condition of the
whole atmosphere. The co-ordination of the observations, and their
geographical representation upon a map, is undertaken by a staff of
trained experts in the Central Bureau in Washington, and through this
organization we obtain a weather-map of the world for every day of the
year. We can now study at leisure the past movements of the atmosphere,
and from these observations we shall surely discover the grand laws
that control aerial phenomena. We shall then not only know, as we do at
present, whence comes the wind and whither it goes, but be able to
predict its movements for the benefit of humanity.
Already we have attained a useful, though limited, power of prediction.
Our Central Bureau daily collects observations by telegraph from all
parts of this continent, and our experts are thus enabled to forecast
the probabilities by a few hours. Day by day the results are
communicated to the public by telegraph in time to avert disaster to
the mariners on our eastern coast, and facilitate agricultural
operations in the Eastern and Middle States.
Although many of the predictions are still falsified by events, the
percentage of fulfilments has become so large as to show that continued
research will in the future give us fresh forms of prediction and
increase the usefulness of this branch of science to mankind.
In all departments of geographical knowledge, Americans are at work.
They have pushed themselves into the front rank and they demand the
best efforts of their countrymen to encourage and support.
When we embark on the great ocean of discovery, the horizon of the
unknown advances with us and surrounds us wherever we go. The more we
know, the greater we find is our ignorance. Because we know so little
we have formed this society for the increase and diffusion of
Geographical knowledge. Because our subject is so large we have
organized the society into four broad sections: relating to the
geography of the land, H. G. Ogden, vice-president; the sea, J. R.
Bartlett, vice-president; the air, A. W. Greely, vice-president; the
geographic distribution of life, C. H. Merriam, vice-president; to
which we have added a fifth, relating to the abstract science of
geographic art, including the art of map-making etc., A. H. Thompson,
vice-president; our recording and corresponding secretaries are Henry
Gannett and George Kennan.
We have been fortunate indeed to secure as Vice-Presidents men learned
in each department, and who have been personally identified with the
work of research.
GEOGRAPHIC METHODS IN GEOLOGIC INVESTIGATION.
BY W. M. DAVIS.
OUTLINE.
Definition of Geography and Geology--Geographic Methods in
Geology--Hutton and Lyell--Marine deposits explained by existing
processes reveal the history of the earth--American Topographers--First
Pennsylvania Survey; geographic form as the result of extinct
processes--Western Surveys; geographic form explained by existing
processes reveals the history of the earth--Deductive
Topography--Comparison with Palæontology--Geographic
Individuals--Classification according to structure--Ideal cycle of
regular development--Interruptions in the Simple Ideal Cycle--Geography
needs ideal types and technical terms--Comparison with the biological
sciences--Teaching of Geography--The water-falls of Northeastern
Pennsylvania as examples of deductive study--Systematic Geography.
The history of the earth includes among many things an account of its
structure and form at successive times, of the processes by which
changes in its structure and form have been produced, and of the causes
of these processes. Geography is according to ordinary definition
allowed of all this only an account of the present form of the earth,
while geology takes all the rest, and it is too generally the case that
even the present form of the earth is insufficiently examined by
geographers. Geographic morphology, or topography, is not yet developed
into a science. Some writers seem to think it a division of geology,
while geologists are as a rule too much occupied with other matters to
give it the attention it deserves. It is not worth while to embarrass
one's study by too much definition of its subdivisions, but it is
clearly advisable in this case to take such steps as shall hasten a
critical and minute examination of the form of the earth's surface by
geographers, and to this end it may serve a useful purpose to enlarge
the limited definition of geography, as given above, and insist that it
shall include not only a descriptive and statistical account of the
present surface of the earth, but also a systematic classification of
the features of the earth's surface, viewed as the results of certain
processes, acting for various periods, at different ages, on divers
structures. As Mackinder of Oxford has recently expressed it, geography
is the study of the present in the light of the past. When thus
conceived it forms a fitting complement to geology, which, as defined
by the same author, is the study of the past in the light of the
present. The studies are inseparable and up to a certain point, their
physical aspects may be well followed together, under such a name as
physiography. Specialization may then lead the student more to one
subject than to the other.
An illustration from human history, where the study of the past and
present has a single name, may serve to make my meaning clear in regard
to the relation of the two parts of terrestrial history, which have
different names. A descriptive and statistical account of a people as
at present existing, such as that which our statistical atlas of the
last Census gives in outline, corresponds to geography in its ordinary
limitation. A reasonable extension of such an account, introducing a
consideration of antecedent conditions and events, for the purpose of
throwing light on existing relations, represents an expanded conception
of geography. The minute study of the rise and present condition of any
single industry would correspond to the monographic account of the
development of any simple group of geographic forms. On the other hand,
history taken in its more general aspects, including an inquiry into
the causes and processes of the rise and fall of ancient nations,
answers to geology; and an account of some brief past stage of history
is the equivalent of paleography, a subject at present very little
studied and seemingly destined always to escape sharp determination. It
is manifest that geology and geography thus defined are parts of a
single great subject, and must not be considered independently.
History became a science when it outgrew mere narration and searched
for the causes of the facts narrated; when it ceased to accept old
narratives as absolute records and judged them by criteria derived from
our knowledge of human nature as we see it at present, but modified to
accord with past conditions.
Geology became a science when it adopted geographic methods. The
interpretation of the past by means of a study of the present proves to
be the only safe method of geologic investigation. Hutton and Lyell may
be named as the prominent leaders of this school and if we admit a
reasonable modification of their too pronounced uniformitarianism, all
modern geologists are their followers. The discovery of the
conservation and correlation of energy gives additional support to
their thesis by ruling out the gratuitous assumption of great results
from vague causes. Causes must be shown to be not only appropriate in
quality, but sufficient in quantity before they can be safely accepted.
But the geographic argument as expounded by the English school deals
almost entirely with processes and neglects a large class of results
that follow from these processes. Much attention is given to the
methods of transferring the waste of the land to the sea and depositing
it there in stratified masses, from which the history of ancient lands
is determined. But the forms assumed by the wasting land have not been
sufficiently examined. It was recognized in a general way that land
forms were the product of denudation, but the enormous volume of
material that had been washed off of the lands was hardly appreciated,
and the great significance of the forms developed during the
destruction of the land was not perceived.
Hutton says a little about the relation of topography to structure;
Lyell says less. The systematic study of topography is largely
American. There is opportunity for it in this country that is not
easily found in Europe. The advance in this study has been made in two
distinct steps: first, in the East about 1840; second, in the West
about 1870. The first step was taken in that historic decade when our
early State surveys accomplished their great work. The Pennsylvania
surveyors then developed topography into a science, as Lesley tells us
so eloquently in his rare little book "Coal and its Topography," 1856,
which deserves to be brought more to the attention of the younger
geographers and geologists of to-day. It presents in brief and
picturesque form the topographical results of the first geological
survey of Pennsylvania. It shows how Lesley and the other members of
that survey "became not mineralogists, not miners, not learned in
fossils, not geologists in the full sense of the word, but
topographers, and topography became a science and was returned to
Europe and presented to geology as an American invention. The passion
with which we studied it is inconceivable, the details into which it
leads us were infinite. Every township was a new monograph." (p. 125.)
Some of the finest groups of canoes and zigzags developed on the folded
beds of the Pennsylvania Appalachians are illustrated from studies made
by Henderson, Whelpley and McKinley, and they certainly deserve the
most attentive examination. I often feel that they have been of the
greatest assistance in my own field work, especially in the efforts I
have made to discover the structural arrangement of the Triassic lava
sheets in the Connecticut valley. But although the intricacies of
Appalachian topography were then clearly seen to depend on the
complications of Appalachian structure, the process of topographic
development was not at that time discovered. "The only question open to
discussion is," says Lesley, "whether this planing down of the crust to
its present surface was a secular or an instantaneous work" (p. 132),
and he decides in favor of the latter alternative. He adds, that to the
field worker, "The rush of an ocean over a continent ... leads off the
whole procession of his facts, and is indispensable to the exercise of
his sagacity at every turn" (p. 166). "The present waters are the
powerless modern representatives of those ancient floods which did the
work" (p. 151).
It is not the least in any spirit of disparagement that I quote these
cataclysmic views, now abandoned even by their author. Great
generalizations are not often completed at a single step, and it is
enough that every effort at advance should have part of its movement in
the right direction. What I wish to show is that topographic form was
regarded in the days of our eastern surveys, even by our first master
of American topography, as a completed product of extinct processes.
Topography revealed structure, but it did not then reveal the long
history that the structure has passed through. The anticlinal valleys,
hemmed in by the even-topped sandstone mountains of middle
Pennsylvania, were found to tell plainly enough that a vast erosion had
taken place, and that the resulting forms depended on the structure of
the eroded mass, but it was tacitly understood that the land stood at
its present altitude during the erosion. The even crest lines of the
mountains and the general highland level of the dissected plateau
farther west did not then reveal that the land had stood lower than at
present during a great part of the erosion, and thus the full lesson of
the topography was not learned. The systematic relation of form to
structure, base level and time; the change of drainage areas by contest
of headwaters at divides; the revival of exhausted rivers by massive
elevations of their drainage areas: all these consequences of slow
adjustments were then unperceived. In later years there seems to be a
general awakening to the great value of these principles, which mark
the second stage in the advance of scientific topography, referred to
above.
It is not easy to sketch the history of this awakening. Ramsay years
ago contributed an element in his explanation of plains of marine
denudation; Jukes opened the way to an understanding of cross valleys;
Newberry excluded fractures from the production of the most
fracture-like of all water ways; and our government surveyors in the
western territories have fully developed the all important idea of base
level, of which only a brief and imperfect statement had previously
been current. I cannot say how far European geographers and geologists
would be willing to place the highest value on the last named element;
to me it takes the place of Lesley's ocean flood, in leading off the
whole procession of outdoor facts. It is indispensable at every turn.
Recently, mention should be made of Löwl, of Prague, who has done so
much to explain the development of rivers, and of McGee, who has
explicitly shown that we must "read geologic history in erosion as well
as in deposition."
If it be true that the greater part of this second advance is American
like the first, it must be ascribed to the natural opportunities
allowed us. The topographers of the Appalachians had a field in which
one great lesson was repeated over and over again and forced on their
attention. The patchwork structure of Europe gave no such wide
opportunity. The surveyors of the western territories again found broad
regions telling one story, and all so plainly written that he must run
far ahead who reads it. It is to this opportunity of rapid discovery
and interpretation that Archibald Geikie alludes in the preface to the
recent second edition of his charming volume on the "Scenery of
Scotland." He says that since the book first appeared he has seen many
parts of Europe, "but above all it has been my good fortune to have
been able to extend the research into western America, and to have
learned more during my months of sojourn there than during the same
number of years in the Old Country." (p. vii.)
Our position now is, therefore, while structure determines form as our
earlier topographers taught, and while form-producing processes are
slow, as had been demonstrated by the English geologists, that the
sequence of forms assumed by a given structure during its long life of
waste is determinate, and that the early or young forms are
recognizably different from the mature forms and the old forms. A young
plain is smooth. The same region at a latter date will be roughened by
the channeling of its larger streams and by the increase in number of
side branches, until it comes to "maturity," that is to the greatest
variety or differentiation of form. At a still later date the widening
of the valleys consumes the intervening hills, and the form becomes
tamer, until in "old age" it returns to the simple plain surface of
"youth." Young mountains possess structural lakes and are drained
largely by longitudinal valleys; old mountains have no such lakes and
have transverse drainage, formed as the growing headwaters of external
streams lead out much water that formerly followed the longitudinal
valleys. Young rivers may have falls on tilted beds, but such are short
lived. Falls on horizontal beds are common and survive on the headwater
branches of even mature rivers. All falls disappear in old rivers,
provided they are not resuscitated by some accident in the normal,
simple cycle of river life. The phases of growth are as distinct as in
organic forms. As this idea has grown in my mind from reading the
authors above named, geography has gained a new interest. The different
parts of the world are brought into natural relations with one another;
the interest that change, growth and life had before given to the
biologic sciences only, now extends to the study of inorganic forms. It
matters not that geographic growth is destructive; it involves a
systematic change of form from the early youth to the distant old age
of a given structure, and that is enough. It matters not that the
change is too slow for us to see its progress in any single structure.
We do not believe that an oak grows from an acorn from seeing the full
growth accomplished while waiting for the evidence of the fact, but
because partly by analogy with plants of quicker development, partly by
the sight of oaks of different ages, we are convinced of a change that
we seldom wait to see. It is the same with geographic forms. We find
evidence of the wasting of great mountains in the wasting of little
mounds of sand; and we may by searching find examples of young, mature
and old mountains, that follow as well marked a sequence as that formed
by small, full grown and decaying oaks. If the relative positions of
the members in the sequence is not manifest at first, we have the
mental pleasure of searching for their true arrangement. The face of
nature thus becomes alive and full of expression, and the conception of
its change becomes so real that one almost expects to see the change in
successive visits to one place.
Now consider the deductive application of this principle. Having
recognized the sequence of forms developed during the wasting life of a
single structure, reverse the conception and we have a powerful
geographic method for geologic investigation. On entering a new
country, apply there the principles learned from the inductive study of
familiar regions, and much past history is revealed; the age of
mountains may be deduced from their form as well as from their rocks;
the altitudes at which a district has stood may be determined by traces
of its old base levels, of which we learn nothing from the ordinary
routine of geologic observation, that is, from a study of the structure
and age of the rocks themselves. The principle is commonly employed
nowadays, but its methods are not formulated, and its full value is
hardly yet perceived. Heim has found traces of successive elevations in
the Alps, proved by incipient base levels at several consistent
altitudes on the valley slopes. Newberry, Powell and Dutton have worked
out the history of the plateau and cañon region from its topography;
Chamberlin and Salisbury write of the young and old topographic forms
of the drift-covered and the driftless areas in Wisconsin; LeConte and
Stephenson have interpreted chapters in the history of California and
Pennsylvania from the form of the valleys. Recently McGee has added
most interesting chapters to the history of our middle Atlantic slope,
in an essay that gives admirable practical exposition of the geographic
methods. In the light of these original and suggestive studies one may
contend that when geographic forms in their vast variety are thus
systematically interpreted as the surface features of as many
structures, belonging to a moderate number of families and having
expression characteristic of their age and accidents, their elevation
and opportunity, then geography will be for the wasting lands what
palæontology has come to be for the growing ocean floors.
An interesting comparison may be drawn here. Fossils were first
gathered and described as individual specimens, with no comprehension
of their relationships and their significance. It was later found that
the fossils in a certain small part of the world, England--that
wonderful epitome of geologic history--were arranged in sequences in
the bedded rocks containing them, certain groups of forms together,
successive groups in shelves, as it were, one over another. Then it was
discovered that the local English scale had a wider application, and
finally it has come to be accepted as a standard, with certain
modifications, for the whole world. The exploring geologist does not
now wait to learn if a formation containing trilobites underlies
another containing ammonites, but on finding the fossils in the two,
confidently and as far as we know correctly concludes that such is
their relative position. Thus the sequence of submarine processes is
made out by the sequence of organic forms. In brief, palæontology has
passed largely from the inductive to the deductive stage.
The geographer first regarded the features of the land as completed
entities, with whose origin he was in no wise concerned. Later it was
found that some conception of their origin was important in
appreciating their present form, but they were still regarded as the
product of past, extinct processes. This view has been in turn
displaced by one that considers the features of the land as the present
stage of a long cycle of systematically changing forms, sculptured by
processes still in operation. Now recognizing the sequence of changing
forms, we may determine the place that any given feature occupies in
the entire sequence through which it must pass in its whole cycle of
development. And then reversing this conception we are just beginning
to deduce the past history of a district by the degree of development
of its features. Geography is, in other words, entering a deductive
stage, like that already reached by palæontology.
The antecedent of deductive topography is the systematic study of land
geography. The surface of the land is made up of many more or less
distinct geographic individuals, every individual consisting of a
single structure, containing many parts or features whose expression
varies as the processes of land sculpture carry the whole through its
long cycle of life. There is endless variety among the thousands of
structures that compose the land, but after recognizing a few large
structural families, the remaining differences may be regarded as
individual. In a given family, the individuals present great
differences of expression with age, as between the vigorous relief of
the young Himalaya and the subdued forms of the old Appalachians; or
with elevation over base level, as between the gentle plain of the low
Atlantic coast and the precocious high plateaus of the Colorado river
region; or with opportunity, as between the last named plateaus with
exterior drainage and the high plains of the Great Basin, whose waters
have no escape save by evaporation or high level overflow; or with
complexity of history, as between the immature, undeveloped valleys of
the lava block country of southern Oregon, and the once empty, then
gravel-filled, and now deeply terraced inner valleys of the Himalaya.
When thus studied, the endless variety of the topography will be
considered in its proper relations, and it will not seem as hopeless as
it does now to gain a rational understanding and appreciation of
geographic morphology.
We should first recognize the fact that a geographic individual is an
area, large or small, whose surface form depends on a single structure.
Boundaries may be vague, different individuals may be blended or even
superposed, but in spite of the indefiniteness, the attempt to
sub-divide a region into the individuals that compose it will be found
very profitable. In a large way the Appalachian plateau is an
individual; the Adirondacks, the terminal moraine of the second glacial
epoch are others. In a small way, a drumlin, a fan delta, a mesa, are
individuals. The linear plateaus of middle Pennsylvania are hybrids
between the well-developed linear ridges of the mountains farther east
and the irregular plateau masses farther west.
A rough classification of geographic individuals would group them under
such headings as plains, plateaus, and rough broken countries of
horizontal structure; mountains of broken, tilted or folded structure,
generally having a distinct linear extension; volcanoes, including all
the parts from the bottom of the stem or neck, up to the lateral
subterranean expansions known as laccolites, and to the surface cones
and flows; glacial drift; wind drift. The agents which accomplished the
work of denudation are also susceptible of classification: rivers
according to the arrangement of their branches, and their imperfections
in the form of lakes and glaciers. The valleys that rivers determine
may be considered as the converse of the lands in which they are cut;
and the waste of the land on the way to the sea is susceptible of
careful discrimination: local soil, talus, alluvial deposits, fan cones
and fan deltas, flood plains and shore deltas. Their variations
dependent on climatic conditions are of especial importance. The
structures formed along shore lines are also significant. This list is
intentionally brief, and the lines between its divisions are not
sharply drawn. It undoubtedly requires discussion and criticism before
adoption. It differs but slightly from the common geographic stock in
trade, but for its proper application it requires that the geographer
should be in some degree a geologist.
The changes in any geographic individual from the time when it was
offered to the destructive forces to the end of its life, when it is
worn down to a featureless base level surface, are worthy of the most
attentive study. The immaturity of the broken country of southern
Oregon, as compared with the more advanced forms of the Basin ranges,
is a case in hand. The Triassic formation of the Connecticut valley is
in some ways of similar structure, being broken by long parallel faults
into narrow blocks or slabs, every block being tilted from its original
position. Russell's description of the blocks in southern Oregon would
apply nicely to those in Connecticut, except that the former have
diverse displacements, while the latter all dip one way; but the
Connecticut individual has, I feel confident, passed through one cycle
of life and has entered well on a second; it has once been worn down
nearly to base level since it was broken and faulted, and subsequent
elevation at a rather remote period has allowed good advance in a
repetition of this process. The general uniformity in the height of its
trap ridges and their strong relief above the present broad valley
bottom, require us to suppose this complexity of history. A given
structure may therefore pass through two or more successive cycles of
life, and before considering the resulting composite history in its
entirety, it would be best to examine cases of simple development in a
single cycle. After this is accomplished, it would be possible to
recognize the incomplete partial cycles through which a structure has
passed, and to refer every detail of form to the cycle in which it was
produced.
The most elementary example that may be chosen to illustrate a simple
cycle of geographic life is that of a plain, elevated to a moderate
height above its base level. The case has already been referred to here
and is given in more detail in an article printed in the proceedings of
the American Association for the Advancement of Science, for 1884, to
which I would now refer. When the succession of forms there described
as developed at a given elevation over base level is clearly perceived,
the occurrence of forms dependent on two different base levels in a
single region can easily be recognized. The most striking example of
such a complex case that I know of is that of the high plateaus of
Utah, as described by Dutton. Northern New Jersey presents another
example less striking but no less valuable: the general upland surface
of the Highlands is an old base level, in which valleys have been cut
in consequence of a subsequent elevation. The plateau developed on the
tilted Triassic beds about Bound Brook is a second base level, cut
during a halt in the rise from the previous lower stand of the land to
its present elevation. There is a parable that illustrates the
principle here presented.