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Earth's Shifting Crust 

A Key to Some Basic Problems of Earth Science 
by CHARLES H. HAPGOOD 

with the collaboration of JAMES H. CAMPBELL 



Foreword by 
ALBERT EINSTEIN 



PANTHEON BOOKS 



Copyright 1958 by Charles H. Hapgood 
Published by Pantheon Books Inc. 
333 Sixth Avenue, New York 14, N. Y. 
Published simultaneously in Canada by 
McClelland & Stewart, Ltd., Toronto, Canada 
Library of Congress Catalog Card No. 58-5504 
Manufactured in the U.S.A. 



to FRED, WILLIE, PRU, and MARY G. 



TABLE OF CONTENTS 

FOREWORD by Albert Einstein j 

AUTHOR'S NOTE: To the Layman and the Specialist 3 

ACKNOWLEDGMENTS 5 

INTRODUCTION: A New Theory 10 

i. Some Unsolved Problems, 10; 2. Crust Displacement as 
a Solution, 13; 3. A Possible Cause of Crust Displace- 
ment, 15 

I. PAST THEORIES OF POLAR SHIFT 24 
i. Older Theories, 24; 2, The Wegener Theory, 26; 

3. New Proposals of Polar Shift, 32 

II. THE ICE AGES 34 
i. The Failure of the Older Theories, 34; 2. The Mis- 
placed Icecaps, 35; 3. World-wide Phases of Cold Weather, 

38; 4. The New Evidence of Radiocarbon Dating, 44; 
5. The New Evidence from Antarctica, 49; 6. Conclu- 
sion, 56 

III. ANCIENT CLIMATES 58 
i. Ages of Bloom in Antarctica, 58; 2. Warm Ages in the 
North, 61; 3. Universal Temperate Climates A Fallacy, 

65; 4. The Eddington-Pauly Suggestion, 70; 5. The Con- 
tribution of George W. Bain, 7156. The Contribution of 
T. Y. H. Ma, 73; 7. On the Rate of Climatic Change, 77 

IV. THE MOUNTAINS 79 

Part I. The Folding and Fracturing of the Crust, 79; 
i. The Problem of Crustal Folding, 80; 2. Campbell's 
Theory of Mountain Building, 90; 3. The Effects of Pole- 
ward Displacement, 100; 4. The Mountain-Building 
Force, 103; 5. Existing Fracture Systems as Evidence for 
the Theory, 104 

Part 1L Volcanism and Other Questions, in; 6. Volcan- 
ism, 1 1 1 ; 7. The Volcanic Island Arcs, 11418 The Heat of 



the Earth, 116; 9. Changing Sea Levels, 120; 10. Some 
Light from Mars, 126; n. Undisturbed Sections of the 
Crust, 127; 12. The Chronology of Mountain Building, 
128 

V. CONTINENTS AND OCEAN BASINS 132 
i. The Central Problem, 132; 2. The Views of the Geo- 
physicists, 134; 3. The Views of the Biologists, 135; 

4. Geologists Allied with Biologists, 139; 5. The Evidence 
of Oceanography, 145; 6. The Deeper Structure of the 
Earth's Crust, 149 

VI. THE SHAPE OF THE EARTH 158 
i. Isostasy and the Icecap, 158; 2. The Antarctic Icecap Is 
Growing, 164; 3. A Suggestion from Einstein, 172; 4. The 
Triaxial Shape of the Earth, 180; 5. The State of Matter 
Below the Crust, 185 

VII. NORTH AMERICA AT THE POLE 193 
i. The Polar Icecap, 193; 2. The Displacement Caused by 

the Ice Sheet, 197; 3. The Cause of the Oscillations of the 
Ice Sheet and the Cause of the Climatic Optimum, 204; 

4. The Glaciation of Europe, 2 10; 5. Changes in Sea Level 
at the End of the Ice Age, 216; 6. Darwin's Rising Beach- 
line in South America, 225 

VIII. THE GREAT EXTINCTIONS 227 
i. The Extinction of the Mammoths, 227; 2. The Mam- 
moth's Adaptation to Cold, 229; 3. The Present Climate 

of Siberia, 233; 4. A Sudden Change of Climate?, 237; 

5. The Beresovka Mammoth, 244; 6. The Interpretation 
of the Report, 249; 7. The Mastodons of New York, 257; 
8. StormI, 266 

IX. EARLIER DISPLACEMENTS OF THE CRUST 272 
i. Introduction, 272; 2. Weakness of the Accepted Glacial 
Chronology, 278; 3. The Beginning of the Wisconsin Gla- 
ciation, 283; a. The Arctic Cores, 284; b. Earlier Phases 

of the Wisconsin Glaciation, 287; 4. Greenland at the 



Pole, 288; a. Cores from the San Augustin Plains, 290; 
b. Some North Atlantic Cores, 293; c. A North Atlantic 
Land Mass?, 297; d. Additional Atlantic Cores, 300; 
5. Alaska at the Pole, 303; 6. The Remoter Past, 308 

X. LIFE 315 
i. The Cause of Evolution, 315; 2. The Problem of Time, 
316; 3. Climate and Evolution, 320; 4. The Distribution 

of Species, 325; 5. The Periods of Revolutionary Change 
in Life Forms, 329; 6. The Extinction of Species, 332; 
7. The Gaps in the Fossil Record, 337; 8. Summary, 339 

XI. CAMPBELL'S MECHANISM OF DISPLACEMENT 340 

i. The Logic of the Evidence, 340; 2. Calculating the 
Centrifugal Effect, 343; 3. The Wedge Effect, 345; 4. Some 
Difficulties, 352; 5. The Calculations, 359; 6. Notes of a 
Conference with Einstein, 361; 7. Isostasy and Centrifugal 
Effect, 365 

XII. CONCLUSION 379 
i. Looking Forward, 379; 2. A General Summary, 386 

APPENDIX: Letters from Albert Einstein and George 

Sarton 390 

GLOSSARY 393 

BIBLIOGRAPHY 396 

INDEX OF NAMES 421 

INDEX OF SUBJECTS 425 



LIST OF ILLUSTRATIONS 

Fig. I. The Centrifugal Effect of the Antarctic Icecap. 

John L. Howard. 18 

Fig. II. Mountain Building: Patterns of Fracture and 

Folding. James H. Campbell. 94 

Fig. III. Vertical View of the Earth with Cross Section at 

96 E. Long. James H. Campbell. 95 

Fig. IV. Patterns of Fracture. James H. Campbell. 96 

Fig. V. Consequences of Displacement: Cross Section of 
Earth at 96 East of Greenwich Showing Centrif- 
ugal Effect of Icecap. John L. Howard. 154 

Fig. VI. Consequences of Displacement: Cross Section of 
Earth at 96 East of Greenwich Showing Hypo- 
thetical Effect of Shift of Crust. John L. 
Howard. 154 

Fig. VII. Antarctica: Three Earlier Locations of the 

South Pole. John L. Howard. 276 

Fig. VIII. Pollen Profile from the San Augustin Plains, 

New Mexico. Clisby and Sears. 291 

Fig. IX. Chronology of Sediments in the North Atlantic 
Cores P-i24(3), P -1 6(5), P-i3o(g). Piggott and 
Urry. 295 

Fig. X. North Atlantic Cores A 172-6, A 199-4, A 180- 

75. Hans E Suess. 301 

Fig. XI. Lithology of Core Samples, Ross Sea, Antarctica. 

Jack L. Hough. 306 

Fig. XII. The Centrifugal Effect of the Icecap. Use of the 
Parallelogram of Forces to Calculate the Tan- 
gential Component. James H. Campbell. 343 

Fig. XIII. A Cross Section of the Earth Showing the Re- 
lation Between the Crust and the Equatorial 
Bulge. James H. Campbell. 346 

Fig. XIV. Various Aspects of the Wedge Effect. James H. 

Campbell. 347 

Fig. XV. The Wedge Effect. James H. Campbell. 348 



"We know that there is no absolute knowledge, that there 
are only theories; but we forget this. The better educated 
we are, the harder we believe in axioms. I asked Einstein 
in Berlin once how he, a trained, drilled, teaching scientist 
of the worst sort, a mathematician, physicist, astronomer, 
had been able to make his discoveries. 'How did you ever do 
it/ I exclaimed, and he, understanding and smiling, gave the 
answer: 

" 'By challenging an axiom I' " 

Lincoln Steffens, Autobiography (p. 816) 



FOREWORD by Albert Einstein 

I frequently receive communications from people who wish 
to consult me concerning their unpublished ideas. It -goes 
without saying that these ideas are very seldom possessed of 
scientific validity. The very first communication, however, 
that I received from Mr. Hapgood electrified me. His idea is 
original, of great simplicity, and if it continues to prove it- 
selfof great importance to everything that is related to the 
history of the earth's surface. 

A great many empirical data indicate that at each point on 
the earth's surface that has been carefully studied, many cli- 
matic changes have taken place, apparently quite suddenly. 
This, according to Hapgood, is explicable if the virtually 
rigid outer crust of the earth undergoes, from time to time, 
extensive displacement over the viscous, plastic, possibly fluid 
inner layers. Such displacements may take place as the conse- 
quence of comparatively slight forces exerted on the crust, 
derived from the earth's momentum of rotation, which in 
turn will tend to alter the axis of rotation of the earth's crust. 

In a polar region there is continual deposition of ice, which 
is not symmetrically distributed about the pole. The earth's 
rotation acts on these unsymmetrically deposited masses, and 
produces centrifugal momentum that is transmitted to the 
rigid crust of the earth. The constantly increasing centrifugal 
momentum produced in this way will, when it has reached a 
certain point, produce a movement of the earth's crust over 
the rest of the earth's body, and this will displace the polar 
regions toward the equator. 

Without a doubt the earth's crust is strong enough not to 
give way proportionately as the ice is deposited. The only 
doubtful assumption is that the earth's crust can be moved 
easily enough over the inner layers. 

The author has not confined himself to a simple presenta- 



2 EARTHS SHIFTING CRUST 

tion of this idea. He has also set forth, cautiously and compre- 
hensively, the extraordinarily rich material that supports his 
displacement theory. I think that this rather astonishing, even 
fascinating, idea deserves the serious attention of anyone who 
concerns himself with the theory of the earth's development. 
To close with an observation that has occurred to me while 
writing these lines: If the earth's crust is really so easily dis- 
placed over its substratum as this theory requires, then the 
rigid masses near the earth's surface must be distributed in 
such a way that they give rise to no other considerable centrif- 
ugal momentum, which would tend to displace the crust by 
centrifugal effect. I think that this deduction might be capa- 
ble of verification, at least approximately. This centrifugal 
momentum should in any case be smaller than that produced 
by the masses of deposited ice. 



AUTHOR'S NOTE: To the Layman and the Specialist 

This book is addressed primarily to the layman. It is intended 
to be read by everyone interested in the earth and in the his- 
tory and future of life on the earth. 

I believe that the most important problems of science that 
is, the most fundamental principles of scientific thought and 
method may be understood by everyone. I think it is the ob- 
ligation of scientists to make these essentials clear, for only in 
this way can science arouse public interest. It is unquestion- 
able that without a public interest science cannot flourish. 

The impression that serious scientific problems are far be- 
yond the understanding of the average man constitutes a seri- 
ous obstacle to the growth of this public interest. A caste 
system of specialists has been created, and it has produced a 
sort of intellectual defeatism, so that the layman tends to 
think that the conclusions he can reach with his own faculties 
are invalid, no matter how carefully he examines the evi- 
dence. This is an error that inhibits the spread of scientific 
knowledge and tends to discourage the recruitment of scien- 
tific workers, for every scientist has been an amateur to start 
with. 

In addressing this book to the general public, I hope not 
only to promote a wider discussion of the basic problems of 
the earth; I hope also that from such increased interest will 
come more recruits for the study of the earth. This book is 
addressed also to the youth of high school and college age, 
who, in my opinion, are perfectly capable of reaching sound 
conclusions on the evidence set forth in it. From many of 
them, in the course of teaching, I have already received not 
only an enthusiastic response, but active and practical help. 

But this book is necessarily addressed also to the specialists 
in the various fields with which it deals. These include geol- 
ogy, geophysics, paleontology, and climatology. It is precisely 



4 EARTH'S SHIFTING CRUST 

here that an attitude discovered among the specialists raises a 
serious problem. There is a natural inclination among them 
to consider, each one, the evidence falling within his own 
field of competence, and that evidence alone. Necessarily, if 
the arguments affecting one field alone are considered, and 
all the rest are put aside, the weight of probability for the 
theory is very greatly reduced, and it becomes easy to con- 
clude that, while interesting, it need not be taken very seri- 
ously. From this it is but a step to the conclusion that the 
theory had better be proved first in one of the other fields: 
it will then be soon enough to invest the necessarily consider- 
able amount of time, effort, and expense in a restudy of the 
basic data affected by the new theory in the specialist's own 
field. 

So it becomes a question of a scientific passing of the buck: 
the paleontologist tends to look to the geologist, the geologist 
to the geophysicist, and the geophysicist to the geologist, for 
the proof of the theory. 

But in the nature of the case, this is a problem for all the 
sciences of the earth together. Here the specialists must be- 
come general readers, and the general reader must take on 
the responsibility of the scientist. By this I mean that the 
reader must examine the facts presented here for himself, 
and draw his own conclusions without looking to any author- 
ity except that of his own reason. If the reader will do that 
and I now include the specialists I have no fear of the conse- 
quences. Either he will accept the theory presented in this 
book or he will be inspired to look for a better one. 



ACKNOWLEDGMENTS 

When it comes time to write an acknowledgment of the assist- 
ance received from others in the preparation of a book, this 
job is sometimes accomplished in a perfunctory way; it is a 
job to be got over with but, at the same time, turned to ad- 
vantage. I do not think that this is fair to the essentially social 
nature of science. The implication is usually obvious that the 
book is, in fact, the work of one or two perspiring and in- 
spired persons, who, by themselves alone, have persevered 
against odds to complete an imperishable product. This dis- 
torts the process by which scientific and, indeed, all original 
work is done. Scientific research is essentially and profoundly 
social. Discoveries are not the product of single great minds 
illuminating the darkness where ordinary people dwell; 
rather, the eminent individuals of science have had many 
predecessors; they themselves have been merely the final or- 
ganizers of materials prepared by others. The raw materials, 
the component elements that have made these great achieve- 
ments possible, have been contributed by hundreds or thou- 
sands of people. Every step in the making of this book has 
been the result of contact with other minds. The work done 
by hundreds of writers over a number of centuries has been 
exploited, and the contributions of contemporary writers 
have been carefully examined. The product represents, I 
should like to think, a synthesis of thought; at the same time 
I hope its original elements will prove valid additions to the 
common stock of knowledge in the field. 

Credit for the initiation of the research that led to this 
book belongs, in the first instance, to students in my classes 
at Springfield College, in Springfield, Massachusetts. A ques- 
tion asked me by Henry Warrington, a freshman, in 1949, 
stimulated me to challenge the accepted view that the earth's 
surface has always been subject only to very gradual change, 



6 EARTH'S SHIFTING CRUST 

and that the poles have always been situated precisely where 
they are today. As the inquiry grew, many students made 
valuable contributions to it, in research papers. Among these 
I may name, in addition to Warrington, William Lammers, 
Frank Kenison, Robert van Camp, Walter Dobrolet, and 
William Archer. 

Our inquiry first took organized form as an investigation 
of the ideas of Hugh Auchincloss Brown, and I am deeply 
indebted to him for his original sensational suggestion that 
icecaps may have frequently capsized the earth, for many sug- 
gestions for research that proved to be productive, for his 
generosity in sharing all his research data with us, and for his 
patience in answering innumerable letters. 

In this early stage of our inquiry, when I was in every sense 
an amateur in many fields into which the inquiry led me, I 
received invaluable assistance from many specialists. These 
included several members of the faculty of Springfield Col- 
lege, especially Professor Errol Buker, without whose kindly 
sympathy our inquiry would have been choked in its infancy. 
Assistance with many serious problems was received from 
Dr. Harlow Shapley, of the Harvard Observatory, Dr. Dirk 
Brouwer, of the Yale Observatory, Dr. G. M. Clemence, of 
the Naval Observatory, and a number of distinguished spe- 
cialists of the United States Coast and Geodetic Survey. 

Our inquiry, in its third year, was involved in a difficulty 
that appeared to be insuperable, and from this dilemma it 
was rescued by an inspired suggestion made by my old friend 
James Hunter Campbell, who thereafter became my constant 
associate in the research project, and my collaborator. I must 
give credit to him for having taken hold of a project that was 
still an amateur inquiry, and transformed it into a solid sci- 
entific project. 

When Mr. Campbell had developed his ideas far enough to 
assure us that the idea we had in mind was essentially sound, 
it became feasible to submit the results of our joint efforts to 
Albert Einstein, and we found him, from then on, a most 
sympathetic and helpful friend. Throughout an extended 



ACKNOWLEDGMENTS 7 

correspondence, and in personal conference, his observations 
either corroborated our findings or pointed out problems 
that we should attempt to solve. With regard to our inquiry, 
Einstein made an exception to his usual policy, which was to 
give his reactions to new ideas submitted to him, but not to 
offer his suggestions for their further development. In our 
case, with an uncanny sense, he put his finger directly upon 
problems that were, or were to be, most baffling to us. We 
had the feeling that he deeply understood what we were try- 
ing to do, and desired to help us. Our association with him 
represented an experience of the spirit as well as of the mind. 

In the later stages of our inquiry, many distinguished spe- 
cialists and friends helped us with particular problems. Help- 
ful suggestions have been contributed by Professor Frank C. 
Hibben, of the University of New Mexico, Professor Bridg- 
man, of Harvard, Dr. John M. Frankland, of the Bureau of 
Standards, the late Dr. George Sarton, Professors Walter 
Bucher and Marshall Kay of Columbia University, Dr. John 
Scott, Mrs. Mary G. Grand, Mr. Walter Breen, Mr. Stanley 
Rowe, Dr. Leo Roberts, Mr. Ralph Barton Perry, Jr., Mrs. 
Mary Heaton Vorse, Mr. Heaton Vorse, Mr. Chauncey 
Hackett, Mrs. Helen Bishop, and Mrs. A. Hyatt Verrill. To 
Dr. Harold Anthony, of the American Museum of Natural 
History, our debt is enormous. It was he who afforded Mr. 
Campbell and me our first opportunity of discussing our 
theories with a group of specialists in the earth sciences, when 
he invited us to talk to the Discussion Group of the Museum. 
In addition, Dr. Anthony has helpfully criticized parts of the 
manuscript, and has helped me to get criticism from other 
experts. Captain Charles Mayo, of Provincetown, Massachu- 
setts, in many long discussions over the years, has contributed 
innumerable valuable suggestions. 

One far-sighted scientist without whose generous help this 
book in its present form would have been impossible is Dr. 
David B. Ericson, of the Lamont Geological Observatory. He 
has contributed many vitally important bibliographical sug- 
gestions, has corrected numerous technical errors, and has 



8 EARTH'S SHIFTING CRUST 

provided needed moral support. I am equally indebted to 
Professor Barry Commoner, of Washington University, who 
not only read the manuscript to suggest improvements of 
content and style, but also helped me in the preparation of 
special articles for publication in the technical journals. Mr. 
Norman A. Jacobs, editor of the Yale Scientific Magazine, 
published the first of these articles. 

During the last year I have received enormous assistance 
from Mr. Ivan T. Sanderson, who, as a biologist, has read the 
manuscript with a critical eye for misuse of technical vocabu- 
lary and for weaknesses in presentation. I have received in- 
valuable help from Professor J. C. Brice, of Washington 
University, who has criticized the whole manuscript from a 
geological standpoint. I am deeply indebted to my aunt, Mrs. 
Norman Hapgood, for the first complete translation from the 
Russian of the report of the Imperial Academy of Sciences 
on the stomach contents of the Beresovka Mammoth, to Mrs. 
Use Politzer for the translation from the German of Ein- 
stein's letter of May 3, 1953, and to Mrs. Maely Dufty for 
assistance with the translation of his Foreword into English. 
To many personal friends, in addition to those mentioned, I 
owe thanks for encouragement and for suggestions that often 
turned out to have major importance. I am indebted to John 
Langley Howard for his assistance with the illustration of 
this book, to Mr. Coburn Gilman, my editor, for his innum- 
erable constructive suggestions and his understanding spirit, 
to Mr. Stanley Abrons for his painstaking work in preparing 
the Glossary, and to Mr. Walter Breen for preparing the Index. 

In the final typing of the manuscript Miss Eileen Sullivan 
has had to encounter and survive difficulties and frustrations 
that only she and I can have an idea of. I am very gateful for 
her help. 

Grateful thanks are extended to all publishers and individ- 
uals who have consented to the use of selections or illustra- 
tions, and in particular to the following: 

Columbia University Press, for quotations from George Gay- 



ACKNOWLEDGMENTS 9 

lord Simpson, Major Features of Evolution; Thomas Y. 
Crowell Co., for a passage from Frank C. Hibben, The Lost 
Americans; Dover Publications, Inc., for quotations from 
Beno Gutenberg, Internal Constitution of the Earth (paper- 
bound, $245); W. H. Freeman 8c Co., for quotations from 
Krumbein and Sloss, Stratigraphy and Sedimentation; Alfred 
A. Knopf, Inc., for quotations from Hans Cloos, Conversa- 
tions With the Earth; N. V. Martinus Nijhoff's Boekhandel 
en Uitgeversmaatschappij, The Hague, for quotations from 
J. H. F. Umbgrove, The Pulse of the Earth; Prentice-Hall, 
Inc., for quotations from R. A. Daly, The Strength and Struc- 
ture of the Earth; Science, for quotations from various issues 
of this magazine; William Sloane Associates, Inc., for quota- 
tions from Thomas R. Henry, The White Continent (Copy- 
right 1950 by Thomas R. Henry); University of Chicago 
Press, for quotations from various issues of the Journal of 
Geology. 

Charles H. Hapgood 
Keene Teachers College, 
October, 1957. 



INTRODUCTION: A New Theory 



i. Some Unsolved Problems 

A few years ago a great scientist, Daly of Harvard, remarked 
that geologists seem to know less about the earth than they 
thought they knew when he was a young man (100). This was 
an extraordinary statement, considering the very detailed 
studies that have been carried out in innumerable geological 
fields during his lifetime. Thousands of scientists, in all the 
countries of the earth, have studied the stratified rocks and 
the records of life contained in them; they have studied the 
structures of mountains and reconstructed their histories; 
they have studied the dynamic forces at work in the earth, 
and have extended our insights to an understanding of the 
features of the ocean bottoms and the deeper structures 
within the earth's crust. 

Yet, despite this vast expansion of our detailed knowledge, 
many of the essential facts of the earth's development have 
escaped us. The late Hans Cloos, in his Conversation with 
the Earth y said, ". . . we know only the unimportant things 
and the details. Of the great slow strides of the earth's gigantic 
history we comprehend hardly anything at all" (85:84). 

To begin with, the origin of the earth is itself still a matter 
of dispute. Until about thirty years ago it was a generally 
accepted theory that it originally condensed out of a hot gas, 
and that it has been cooling and contracting ever since. This 
was the "nebular theory/' In recent decades difficulties have 
piled up in connection with this assumption, and at the pres- 
ent time an entirely opposite view is held by many geophysi- 

NOTE: Figures referring to specific sources listed in the Bibliography (p. 
396) are inserted in parentheses throughout the text. The first number indi- 
cates the correspondingly numbered work in the Bibliography, and the num- 
ber following a colon indicates the page. 



INTRODUCTION 11 

cists. The new idea is that the earth may have started as a 
small, cold planetesimal. It may have grown simply by attract- 
ing to itself many smaller particles, such as meteorites and 
meteoritic dust. It may have grown hot as a result of the 
internal pressures caused by its increasing mass, and because 
of the effects of the radioactivity of many bits of the matter it 
picked up on its endless journey through interstellar space. 
Even a cursory glance at the current literature on this sub- 
ject reveals the formidable character of the challenge it pre- 
sents to the old theory and indeed to the whole structure of 
geological theory based upon it. Dr. Harold C. Uf ey reaches 
the conclusion, from impressive evidence, that the earth must 
have been formed at temperatures below the melting points 
of silicate rocks (437:112). He quotes the opinion of Bowen 
that the earth was formed as a solid (438:110). Gutenberg 
refers to the work of several geophysicists who have advanced 
similar views (194:191-92). Olivier argued, in 1924, that 
meteoric phenomena can be understood only in terms of a 
growing earth. He remarked, "The planetesimal hypothesis 
is the one to which we are logically led when we attempt to 
explain meteoric phenomena" (337:272). Coleman pointed 
to evidence that some of the ice ages in remote geological 
periods seem to have been colder than those of the more re- 
cent past (87:102). Slichter, summarizing the results of a con- 
ference of chemists, geologists, and geophysicists devoted to 
this subject, said, 

... In accordance with recent theories, the earth probably has 
grown by the accretion of relatively cool materials which were not 
molten at the outset. The chemists strongly favored the cool type of 
origin. . . . Our conceptions of the development of the primitive 
earth are, to say the least, obscure. It is even uncertain whether the 
earth today is cooling or heating at depth, but the odds seem to favor 
the hypothesis of a heating earth (395:511-12). 

Inasmuch as it seems evident that neither view of the 
origin of the earth has been established, the layman is forced 
to conclude that the problem of the origin of the earth is 
unsolved. 



12 EARTH S SHIFTING CRUST 

More than twenty-five years ago, the geologist William H. 
Hobbs pointed out the consequences of the breakdown of 
the nebular theory, so far as geology was concerned: 

Far more than is generally supposed, the recent abandonment of 
the nebular hypothesis to account for the origin of the universe, must 
carry with it a rewriting of our science. This is particularly true of 
geology, for all that concerns seismology, volcanology, and the whole 
subject of the growth of continents and mountains (2i5:vii-viii). 

But not only has there been no rewriting: actually, the 
very abandonment of the nebular hypothesis has not yet 
penetrated to the consciousness of the public. It is even true 
that many geologists, when they are addressing their remarks 
to the general public, write as if the cooling of the earth from 
an original molten state had never been questioned. 

Within the frame of reference of this uncertainty regarding 
the earth's beginning, most geologists today unhesitatingly 
confess that we do not understand the origin of continents, 
ocean basins, mountain chains, or the causes of volcanic ac- 
tion. We have never solved the mystery of ice ages in the 
tropics, nor the equally strange mystery of the growth of 
corals and warm-climate flora in the polar zones. There is a 
dispute as to whether the present climatic zones have existed 
continuously from the earth's beginning. If so, we cannot 
account at all for the greater part of the fossils of plants and 
animals of the past that did not live within the limits of the 
present zones. If the zones have not continuously existed, no 
one has been able to show what factor can have operated to 
even out temperatures from pole to pole. When we turn to 
the theory of evolution, we find that the unsolved problems 
of origin, development, and extinction of species are many 
and basic. Everybody agrees that evolution has occurred, but 
nobody pretends to know how it happened. Our ideas of the 
tempo at which geological change has occurred in the past 
have been challenged in the most dramatic fashion by new 
evidence produced by techniques of dating based on radio- 
active isotopes. These new techniques have served to under- 
line and emphasize the bankruptcy of the present theory of 



INTRODUCTION 1$ 

the earth. They have, indeed, created many more problems 
than they have solved. 

It became obvious to me, as I reviewed these problems, and 
went back over the controversies that had marked their con- 
sideration, that a sort of common denominator was present. 
I examined the original sources, and here I noticed that in 
the controversies that have raged among geologists over these 
separate questions in the last seventy-five years, somebody 
usually tried to explain the particular problem in terms of 
changes in the position of the poles. This, I found, was the 
common denominator. The authors of such theories, unfor- 
tunately, were never able to prove their assumptions. The 
opponents of the notion of polar change always managed to 
point out fallacies that seemed decisive. At the same time, no 
one was able to reconcile all the evidence in the different 
fields with the idea that the poles have always been situated 
where they are now on the earth's surface. 

The theory here presented would solve these problems by 
supposing changes in the positions of the poles. Campbell has 
suggested that the changes have occurred not by reason of 
changes in the position of the earth's axis, but simply through 
a sliding of its crust. There is nothing new about this idea. 
It has been brought forward repeatedly over the last seventy- 
five years, and is advocated today by a number of scientists. 
This book brings together, I hope in comprehensible form, 
the evidence from many fields that argues for such shifts, evi- 
dence in many cases accumulated by others. In addition, it 
contains a new element. Campbell's concept of the mecha- 
nism by which movements of the earth's crust are accounted 
for is completely new, although elements of it have been con- 
tributed by others. 



2. Crust Displacement as a Solution 

To understand what is involved in the idea of a movement, 
or displacement, of the entire crust of the earth, certain facts 



14 EARTH'S SHIFTING CRUST 

about the earth must be understood. The crust is very thin. 
Estimates of its thickness range from a minimum of about 
twenty to a maximum of about forty miles. The crust is made 
of comparatively rigid, crystalline rock, but it is fractured in 
many places, and does not have great strength. Immediately 
under the crust is a layer that is thought to be extremely 
weak, because it is, presumably, too hot to crystallize. More- 
over, it is thought that pressure at that depth renders the 
rock extremely plastic, so that it will yield easily to pressures. 
The rock at that depth is supposed to have high viscosity; 
that is, it is fluid but very stiff, as tar may be. It is known that 
a viscous material will yield easily to a comparatively slight 
pressure exerted over a long period of time, even though it 
may act as a solid when subjected to a sudden pressure, such 
as an earthquake wave. If a gentle push is exerted horizon- 
tally on the earth's crust, to shove it in a given direction, and 
if the push is maintained steadily for a long time, it is highly 
probable that the crust will be displaced over this plastic and 
viscous lower layer. The crust, in this case, will move as a 
single unit, the whole crust at the same time. This idea has 
nothing whatever to do with the much discussed theory of 
drifting continents, according to which the continents drifted 
separately, in different directions. The objections to the drift- 
ing continent theory will be discussed later. 

Let us visualize briefly the consequences of a displacement 
of the whole crustal shell of the earth. First, there will be the 
changes in latitude. Places on the earth's surface will change 
their distances from the equator. Some will be shifted nearer 
the equator, and others farther away. Points on opposite sides 
of the earth will move in opposite directions. For example, if 
New York should be moved 2,000 miles south, the Indian 
Ocean, diametrically opposite, would have to be shifted 2,000 
miles north. All points on the earth's surface will not move 
an equal distance, however. To visualize this, the reader need 
only take a globe, mounted on its stand, and set it in rotation. 
He will see that while a point on its equator is moving fast, 
the points nearest the poles are moving slowly. In a given 



INTRODUCTION 15 

time, a point near the equator moves much farther than one 
near a pole. So, in a displacement of the crust, there is a me- 
ridian around the earth that represents the direction of the 
movement, and points on this circle will be moved farthest. 
Two points go degrees away from this line will represent the 
"pivot points'* of the movement. All other points will be dis- 
placed proportionally to their distances from this meridian. 
Naturally, climatic changes will be more or less proportionate 
to changes in latitude, and, because areas on opposite sides 
of the globe will be moving in opposite directions, some 
areas will be getting colder while others get hotter; some will 
be undergoing radical changes of climate, some mild changes 
of climate, and some no changes at all. 

Along with the climatic changes, there will be many other 
consequences of a displacement of the crust. Because of the 
slight flattening of the earth, there will be stretching and 
compressional effects to crack and fold the crust, possibly 
contributing to the formation of mountain ranges. There 
will be changes in sea level, and many other consequences. In 
this book the potential consequences will be discussed in de- 
tail, and evidence presented to show that such displacements 
have frequently occurred in the earth's history, and that they 
provide an acceptable solution to the problems I have men- 
tioned above. 1 



3. A Possible Cause of Crust Displacement 

Some years ago Mr. Hugh Auchincloss Brown, an engineer, 
developed a theory that great polar icecaps might shift the 
poles by capsizing or careening the earth as a whole. He had a 
simple idea, suggested by his engineering experience. This 
was the concept of the centrifugal effect that may arise from 

i To follow the argument presented in this book, the reader will find it help- 
ful to use a globe. A small one will do. A globe is better than flat maps for 
the purpose of following the many simultaneous changes involved in a dis- 
placement of the crust. 



i6 EARTH'S SHIFTING CRUST 

the rotation of a body, if the body is not perfectly centered 
on its axis of rotation. Everyone has seen examples of the 
operation of centrifugal force. The principle can be demon- 
strated by the ordinary washing machine. I once put a heavy 
rug, all rolled up into a compact ball, into a washing ma- 
chine, and of course when the machine was set in motion all 
the weight remained on one side of the axle. The rotation 
produced a very powerful sidewise heave. The centrifugal 
effect was sufficient to rip the bolts up out of what had been 
a fine antique floor. Engineers know that the slightest inac- 
curacy in the centering of a rapidly rotating mass, such as a 
flywheel, can result in shattering the rotating body. 

Brown pointed out that a polar icecap is an enormous body 
placed on the earth's surface, and not perfectly centered on 
the axis of rotation. It must therefore create centrifugal 
effects, tending to unbalance the earth. He called attention to 
certain facts about Antarctica. Antarctica is a large continent, 
about twice the size of the United States. It is almost entirely 
covered by ice, and the ice is enormously thick. Antarctica 
contains many great mountain chains, some of them compara- 
ble to the Alps or the Rocky Mountains, but the ice is so 
thick that it reaches the tops of most of them, and sweeps over 
them. The ice sheet is thought to average a mile in thickness, 
and it may be twice as thick in places. It may contain as much 
as 6,000,000 cubic miles of ice. Much of this ice is an extra 
weight on the earth's crust because it has accumulated so fast 
that there has been insufficient time for the earth's crust to 
sink and adapt to it. As we shall see, Brown's surmise that the 
Antarctic icecap has developed rapidly, and is growing even 
now (rather than retreating), is well supported by much re- 
cent evidence. 

With respect to the eccentricity of this mass, Brown 
pointed out that the earth is known to wobble slightly on its 
axis. The wobble amounts to about fifty feet, and the earth 
completes one wobble in about fourteen months. This means 
that the whole planet, including the icecap, is always off 
center by about that amount. Brown thought that this slight 



INTRODUCTION 1? 

eccentricity would, because of the enormous mass of the ice- 
cap, produce a great centrifugal effect tending to unbalance 
the globe. He made some mathematical calculations to show 
the possible magnitude of the effect. He suggested that, at 
some point, the icecap would grow so large that the centrif- 
ugal effect would suffice to shatter the crust in the earth's 
equatorial bulge, and permit the earth to wobble farther off 
center. Then the increasing radius of eccentricity would 
cause an increase of the centrifugal effect by arithmetical 
progression, until the earth capsized. He likened the earth's 
equatorial bulge its slightly greater diameter through the 
equatorto a flywheel, which would be shattered by the cen- 
trifugal effect of the icecap. 

When I first began to study Brown's ideas, I examined his 
two basic assumptions with some care. The first was the as- 
sumption of the centrifugal effect of bodies rotating off 
center, and that was sound enough. The second was the 
assumption that the equatorial bulge acted as a stabilizing 
flywheel to keep the earth steady on its axis. The investiga- 
tion of this assumption involved long research. I finally found 
unequivocal support for Brown's contention in the works of 
James Clerk Maxwell and obtained further confirmation of 
it in correspondence with Dr. Harlow Shapley, of the Har- 
vard Observatory, Dr. Dirk Brouwer, of the Yale Observa- 
tory, and Dr. Harold Jeffreys, of Cambridge University, 
England. 

I now sought to find, if I could, the ratio of the unstabiliz- 
ing centrifugal effect of the icecap to the stabilizing effect of 
the bulge. It was clear that the force of the icecap would 
either have to overcome the total stabilizing centrifugal effect 
of the bulge, or it would have to shatter the crust, so that the 
earth could start to rotate farther off center, thereby initi- 
ating a chain reaction of increasing centrifugal effects. 

The first task was to estimate the centrifugal effect of the 
icecap. Here I thought that Brown had committed an over- 
sight, to the disadvantage of his own theory. He considered 
die eccentricity of the icecap to be due to the earth's fifty-foot 



i8 



EARTH S SHIFTING CRUST 



wobble. I saw, on looking at the map, what seemed to me a 
much greater eccentricity. It was obvious that the South Pole 
was not at all in the center of the continent. This being so, 
then the icecap, which covers virtually all the continent, 
could not be centered at the pole. It seemed to me that the 



90*WEST FROM GREENWICH 




96' 90 % EAST FROM GREENWICH 



Fig. I. The Centrifugal Effect of the Antarctic Icecap 

To visualize the centrifugal effect that may be caused by the Antarctic 
icecap, the reader should imagine the map of Antarctica actually rotat- 
ing. The continent of Antarctica makes one complete rotation every 



INTRODUCTION 19 

first step must be to locate the geographical center of mass 
of the Antarctic icecap, and then to apply the standard for- 
mula used in mechanics to determine the centrifugal effect. 
I asked my friend, Errol Buker, of the Springfield College 
faculty, to locate the geographical center. He and later Mr. 
Campbell each separately solved the problem, and obtained 
closely similar results. It appeared that the center was be- 
tween 300 and 345 miles from the pole, allowing a margin 
of error for the uncertainties involved in the present state of 
Antarctic exploration. This, of course, involved a centrifugal 
effect thousands of times greater than that which could be 
derived from Brown's assumptions. On this basis Buker calcu- 
lated the centrifugal effect, and the calculation was later re- 
vised by Campbell (Chapter XI). The calculation applied to 
the present Antarctic icecap only. The ice around the North 
Pole could be disregarded because, except for the Greenland 
cap, it is merely a thin shell of floating ice. The presence of 
the Arctic Ocean prevents any thick accumulation of ice. 

twenty-four hours with the rotation of the earth, and this is what causes 
the centrifugal effect. 

The point at the intersection of the two meridians is the South Pole. 
This is one end of the axis on which the earth rotates. The small circle 
drawn about this point is shown passing through an off-center point 
about five degrees (or 345 miles) from the pole. This point is, so far as 
we can now estimate, the geographical center of mass of the icecap, 
which does not coincide with the South Pole because of the asymmetric 
shape of the continent. 

The two larger circles, one drawn about the pole as a center and one 
drawn about the icecap's eccentrically located center of mass, are a me- 
chanical convention used by engineers to illustrate the centrifugal effects 
of off-center rotation. If the map is visualized as rotating, the inner 
circle drawn about the pole represents the earth in stable rotation, while 
the outer circle, drawn about the center of the icecap, is undergoing 
violent eccentric gyration. The eccentricity results in an outward cen- 
trifugal "throw" in the direction of the meridian of 96 E. Long. The 
two arrows show how the force of the earth's rotation is transformed 
into a centrifugal effect at right angles to trie earth's axis, an effect pro- 
portional to the weight of the ice and the distance of its center of mass 
from the axis. 



2O EARTH'S SHIFTING CRUST 

The second problem was to measure the stabilizing cen- 
trifugal effect of the bulge. Since there was no record of any 
work having been done previously on this problem, it was 
necessary to work it all out from fundamentals. It involved 
difficult physical and mathematical problems. Here I was 
extremely fortunate in obtaining the generous co-operation 
of several of the distinguished specialists of the United States 
Coast and Geodetic Survey. They gave me a calculus with 
which Mrs. Whittaker Deininger, of the Smith College fac- 
ulty, obtained a quantity for the stabilizing effect of the 
bulge. 

Now we had two quantities that could be compared with 
each other: the centrifugal effect of the icecap, tending to 
upset the earth, and the stabilizing effect of the bulge. Unfor- 
tunately for the theory as it then stood, it appeared that the 
stabilizing effect of the bulge was greater than the eccentric 
effect of the icecap by several thousand times. 

There is no question that this result, had it come earlier, 
would have brought the investigation to an end. But my geo- 
logical research had been proceeding actively for more than 
two years and had produced such impressive evidence that I 
felt much opposed to the complete abandonment of the proj- 
ect. I discussed the difficulty that had arisen with my friend 
Campbell. It was indeed fortunate that I did so, for the solu- 
tion came from him when he suggested that if the icecap did 
not have sufficient force to careen the whole planet, it might 
have sufficient force to displace the earth's crust over the 
underlying layers. As a sequel to this conversation, Mr. 
Campbell continued to work, for a number of years, on the 
implications of his suggestion. The details of his mechanism 
to account for crust displacement are presented in Chapter 
XI. 

The hypothesis that has emerged as the result of this com- 
bination of elements is distinguished by its economy of as- 
sumptions. It appealed to Albert Einstein because of its 
simplicity. It appeared to him that it might be possible, on 
the basis of the simple common denominator of this theory 



INTRODUCTION 21 

of displacement, to solve the many complex and interrelated 
problems of the earth that have so long resisted solution. 

The simplicity of the idea may raise the suspicion that it 
can hardly be so very new. How can anything so extremely 
simple as the application of the formula for calculating cen- 
trifugal effects, a formula which appears in every high-school 
textbook of physics, to a polar icecap, have been completely 
overlooked? This thought occurred to me, but I found to 
my surprise that, despite the simplicity of the idea, it was 
one that had never been investigated. When I first discussed 
it with Professor Bridgman, at Harvard, he had the impres- 
sion that it was a good idea; he called it a real problem, but 
he said he could not believe that it had never been consid- 
ered by science. He suggested that I take it up with Pro- 
fessor Daly. I did so, and Professor Daly agreed that it was a 
real problem, but assured me that it had never, to his knowl- 
edge, been investigated. And so it turned out. I have looked 
pretty far through the technical literature and have found no 
studies covering it. Dr. George Sarton, the historian of sci- 
ence, confirmed this finding when he wrote me that "the 
combination of ideas is so new that the history of science has 
nothing to contribute to its understanding" (p. 391). 

This book has been written with three objectives in mind. 
I have sought, in the first place, to establish beyond a reason- 
able doubt that numerous displacements of the earth's crust 
have occurred. I think that this idea may now be accepted 
without too much difficulty, especially in view of much recent 
work in the field of terrestrial magnetism. Secondly, I have 
tried to describe a mechanism to account for displacements 
(this is essentially the work of Mr. Campbell) and to present 
evidence showing that this mechanism alone can account for 
the facts. My third purpose has been to show that the hy- 
pothesis of crust displacement provides an acceptable solu- 
tion of many of the problems of the earth. 

It is quite natural that at first numerous objections should 
be raised to this theory. In our correspondence with special- 
ists the principal issues that have come up to raise doubts 



22 EARTH'S SHIFTING CRUST 

include the following: whether we have properly estimated 
the magnitude of the centrifugal effect; whether there is any 
layer below the crust weak enough to permit crust displace- 
ment; whether the Antarctic icecap is really growing, as the 
theory requires, or is in retreat; whether the centrifugal effect 
we postulate would not in practice merely cause the icecap to 
flow off from the Antarctic continent into the sea, rather than 
transmit its push to the crust; whether the thrust of the ice- 
cap, if it was transmitted to the crust, would be transmitted to 
the crust as a whole, as the theory requires, or would be ab- 
sorbed in local readjustments of the crust; whether, if both 
the poles happened to fall in water areas, icecaps would not 
cease to develop, and thus the whole process of crust displace- 
ment be brought to an end; why, if crust displacements have 
been frequent in geological history, there are not evidences 
of more icecaps in the geological record; why, with that as- 
sumption, we find some rock formations that appear to have 
been undisturbed since the earliest times. All these objec- 
tions, and many more, are fully, and I hope fairly, discussed 
in the following chapters. Therefore, if the reader finds him- 
self asking questions that do not appear to be answered, I 
hope he will have patience. He may find that they are an- 
swered in later parts of the book. 



INTRODUCTION 



TABLE I 



The Geological Periods 

(After Krumbein and Sloss, 258:15) 



ERA 

Cenozoic 



Mesozoic 



Paleozoic 



Pre-Cambrian 



PERIOD 

Quaternary 

Tertiary 



Cretaceous 
Jurassic 

(Liassic) 
Triassic 

(Thaetic) 

Permian 
Pennsylvanian 

(Carboniferous) 
Mississippian 
Devonian 
Silurian 
Ordovician 
Cambrian 

Keweenawan 
Huronian 
Tamiskamian 
Kewatinian 



EPOCH 

Present 
Pleistocene 

Pliocene 
Miocene 
Oligocene 
Eocene 

(Paleocene) 



I : PAST THEORIES OF POLAR SHIFT 



/. Older Theories 

Of all the questions that have been debated in the sciences o 
the earth, perhaps the most fundamental and the most in- 
volved is that of the stability of the poles. This question has 
bedevilled science for about a hundred years. Despite every 
effort to establish the view that the poles have shifted during 
the history of the earth, or to prove that they have not, the 
controversy is just as lively today as ever. In fact, discussion 
of the issue has become much more active during the last 
decade. The new evidence bearing on this question, as we 
shall see, now strongly favors the idea of polar shift. 

When the term "polar shift" is used, it may have several 
meanings. It may mean a change of the position of the earth's 
axis, with reference to the stars. Everyone has seen pictures 
of the solar system, with the earth, planets, and sun shown in 
relationship to one another. The earth is always shown 
slightly tipped. Its axis does not run straight up and down at 
right angles to the plane of the sun's equator, but slants at 
an angle. 

Now, there is no doubt but that any change in the position 
of this axis would be very important to us. It might mean, 
for example, that the South Pole would point directly at the 
sun. We would then have one hot pole and one cold pole. 
The hot pole would never have any night, and the cold pole 
would never have any day. The occurrence of this kind of 
polar shift has seldom been supposed, for the reason that no 
force capable of shifting the axis has ever been imagined, 
other than, possibly, a major interplanetary collision. 

A second cause of the shifting of the poles with reference to 
points on the earth's surface would be a change in the posi- 
tion of the whole planet on its axis, without change of the 



PAST THEORIES OF POLAR SHIFT 25 

position of the axis. The axis would point in the same direc- 
tiontoward the same stars but by a careening motion of 
the planet other points would be brought to the poles. Not 
the axis, but the whole planet, would have moved or swivelled 
around. This is the sort of change proposed by Brown. 

As I have already mentioned, the principal obstacle to a 
shift of the earth on its axis lies in the existence of the earth's 
equatorial bulge, which acts like the stabilizing rim of a gyro- 
scope. The early writers on this question, such as Maxwell 
(296) and George H. Darwin (105), all recognized that a 
shifting of the planet on its axis to any great extent would re- 
quire a force sufficient to overcome the stabilizing effect of 
the bulge. But they were unable to see what could give rise 
to such a force, and dismissed the idea of a shift of the planet 
on its axis as utterly impossible and, in fact, not worth dis- 
cussing. 

This, however, left the evidence unaccounted for, and such 
evidence, from many sources, continued to accumulate. Forti- 
fied by their very strong conviction that a shift of the planet 
on its axis was impossible, astronomers and geologists in- 
sisted that all this evidence, such as fossil corals from the 
Arctic Ocean, coal beds and fossil water lilies from Spitz- 
bergen, and many other evidences of warm climates in the 
vicinity of both the poles, simply must be interpreted in ac- 
cordance with the assumption that the poles had never 
changed their positions on the face of the earth. This placed 
quite a strain upon generations of geologists, but their imagi- 
nations were usually equal to the task. They were fertile in 
inventing theories to account for warm climates in the polar 
zones at the required times, but these theories were never 
based on substantial evidence. Moreover, they never ex- 
plained more than a small number of the facts, while essen- 
tially they conflicted with common sense. We shall have 
occasion to return to them again in later chapters, where the 
statements I have just made will be fully documented. 

The discontent of the biologists and paleontologists, who 
were constantly finding fossil fauna and flora in the wrong 



s6 EARTH'S SHIFTING CRUST 

places, finally boiled over, and resulted in a number of new 
theories for polar change. New proposals were .frequently ad- 
vanced in the i88o's and iSgo's and later, but they were met 
by the unyielding resistance of the highest authorities, basing 
themselves on the positions taken by the persons already 
mentioned. Moreover, it was easy to show defects and contra- 
dictions in these various theories, and to discredit them, one 
after another. All the assaults were successfully beaten back, 
except one. 



2. The Wegener Theory 

The exception proved to be the theory of Alfred von We- 
gener. The latter was a good scientist, though not a geologist. 
He was unwilling to be satisfied with theories that would 
account for only a few of the facts. He had a passion for 
broad, inclusive principles supported by tangible evidence. 
He found quantities of evidence that could not, in his opin- 
ion, be reconciled with the present positions of the poles. 
Inasmuch as the doctrine of polar permanence (and it was a 
doctrine any challenge to which evoked remarkable fury 
from recognized authorities) forbade any thought that the 
poles themselves had moved, or that the earth had shifted on 
its axis, Wegener suggested that the continents had moved. 
This would have precisely the same effect, for it would mean 
that, at different times, different areas would be found at the 
poles. And this was, in effect, a third way to account for shift- 
ings of the geographical locations of the poles. 

Wegener imagined that the continents, formed of light 
granitic and sedimentary rocks, had once composed a single 
land mass, but had been split and set in motion, drifting over 
a plastic substratum of the continents and oceans. He thought 
of this sublayer as really plastic and viscous, rather than 
rigid and strong. From a vast amount of fossil evidence of 
the plant and animal life of the past, he imagined that he 
could reconstruct the actual paths of the continents over 



PAST THEORIES OF POLAR SHIFT 2? 

long periods of time. He proposed to explain the ice ages by 
this theory; he suggested that during the last ice age in the 
Northern Hemisphere, Europe and America had lain close 
together near the pole but that, since then, they had drifted 
apart. 

Wegener's theory had great appeal. This was not because 
all of the evidence supported it, nor because its mechanics 
were very plausible, but because it was the only theory that, 
at the time, could make sense of the evidence of the fossil 
flora and fauna. 

There were a number of weaknesses in the structure of 
this theory. One of these was that the evidence from different 
areas, for the same geological period, would not produce 
agreement as to where the poles were situated at a given time. 
Chancy, for example, wrote, "It is amusing to note . . . that 
in taking care of their Tertiary forests, certain Europeans 
have condemned ours to freezing. . . ." (72:484). 

Wegener recognized the seriousness of this difficulty: 

Although the grounds for the shifting of the poles (in certain 
periods of the earth's history) are so compelling, nevertheless it can- 
not be denied that all previous attempts to fix the positions of the 
poles continuously throughout the whole geological succession have 
always led to self-contradiction, and indeed to contradiction of so gro- 
tesque a kind that it is not to be wondered at that the suspicion arises 
that the assumption of the shifting of the poles is built on a fallacy 
(45 : 94-95)- 

This difficulty, basic as it was, was by no means the worst. 
By various methods the knowledge of the structure of the 
earth's crust was extended, and it was finally found that the 
rock under the oceans, which Wegener had thought to be 
plastic enough for the continents to drift over it, is in fact 
very rigid. This means that the continents cannot drift with- 
out displacing a layer of rigid rock under the oceans, a layer 
thought to be at least twenty miles thick and comparatively 
strong. It is therefore impossible for the continents to drift. 
Dr. Harold Jeffreys, the noted geophysicist, basing his opin- 
ion on the evidence for a rigid and comparatively strong 



28 EARTH'S SHIFTING CRUST 

ocean floor, said, ". . . There is therefore not the slightest 
reason to believe that bodily displacements of continents 
through the lithosphere are possible" (238:304; 239:346). 
The lithosphere, of course, is the crust. The geophysicist 
F. A. Vening Meinesz, according to Umbgrove, conclusively 
proved the considerable strength of the crust under the 
Pacific (430:70). 

One of the arguments most frequently heard in favor of 
the Wegener theory is based on the apparent correspondence 
in shape between certain continents. It would seem, for ex- 
ample, that South America might be fitted together with 
Africa, and so on. It is claimed that this is evidence that the 
two were once parts of one land mass, which must have 
broken in two. It is even claimed that rock formations on 
opposite sides of the Atlantic match. However, some years 
ago, K. E. Caster and J. C. Mendes, two geologists who de- 
sired to prove this theory, spent a vast amount of time in 
South America, and travelled about 25,000 miles carrying on 
field investigations in order to compare in detail the rock 
formations of South America with those of Africa. Their 
conclusion was that the rock formations did not prove the 
theory. Neither, however, did the evidence they had found 
disprove it. They added, "Only time and more facts can 
settle the issue" (69:1173). Professor Walter Bucher, former 
President of the Geological Society of America, also answered 
this particular point. He published a map showing the 
United States as it would look if flooded up to 1,000 feet 
above the present sea level. The map shows that the eastern 
and western sides of the resulting inland sea correspond 
(57 : 459)- Thus, if the sea were there now, it would look as 
if the two parts of North America had drifted apart. An alter- 
native explanation of such parallel or corresponding features 
will be suggested in a later chapter. 

Another objection to the Wegener theory is that it assumes 
that the sea bottoms are smooth plains. This assumption is 
necessary for the theory, for otherwise the continents could 
not drift over the ocean basins. As the result of the oceano- 



PAST THEORIES OF FOLAR SHIFT 2Q 

graphic work of recent years, it has been discovered, in con- 
tradiction to this, that there are mountain ranges on the 
bottoms of all the oceans, and that some of these ranges are 
comparable in size to the greatest mountain ranges on land. 
Furthermore, several hundred volcanic mountains have been 
discovered spread singly over the ocean floors, many of them 
apparently of great age. 

The Wegener theory involved the corollary that, as the 
continents had drifted very slowly across the smooth ocean 
floors, these floors had accumulated sediment to great thick- 
nesses. It was thought that this sediment should provide an 
unbroken record for the whole period of geological time 
since the formation of the oceans. The greatest surprise of 
recent oceanographic exploration, however, has been the 
discovery that this supposed layer of sediment is nonexistent. 
The layer of sediment on the ocean bottom is uneven, in 
some places only a few feet or a few inches thick, and is rarely 
of great thickness. The matter of submarine sediments will be 
discussed more fully in later chapters. 

Another startling contradiction to the Wegener theory is 
presented by recent data that have drastically changed our 
former ideas regarding the date of the last ice age in North 
America. We have learned, through the new technique of 
radiocarbon dating, that this ice age ended only 10,000 years 
ago. In Wegener's time it was considered by geologists that 
the ice age came to an end at least 30,000 years ago. Since 
Wegener supposed that Europe and North America had been 
situated close together and not far from the pole during the 
ice age, the new data have the effect of requiring an incredi- 
ble rate of continental drift. Three thousand miles of drift 
in 10,000 years would amount to about 1,500 feet a year. 
Furthermore, movement at something like this rate must 
still be going on, for the momentum of a continent in motion 
would be tremendous. And what would be the consequence 
of a continuing movement at this rate? It would mean that 
oceanic charts would have to be revised every few years, and 
that shipping companies would have frequently to augment 



jo EARTH'S SHIFTING CRUST 

their fares, because of the ever-increasing distance between 
America and Europe. 

To cap the case, Gutenberg has shown that the various 
forces that Wegener depended upon to move the continents 
are either nonexistent or insufficient (194:209), while another 
geophysicist, Lambert, has stated that they amount to only 
one millionth of what would be required (64:162). 

It is interesting to note that despite the quite overwhelm- 
ing character of these objections, attempts are still made to 
rehabilitate or rescue the Wegener theory. Daly attempted, 
some years ago, to find a better source of energy for moving 
the continents (98); Hansen cleverly suggested that the centrif- 
ugal effects of icecaps might have moved the continents 
(199). A contemporary Soviet plant geographer, while recog- 
nizing the objections, nevertheless remarked of the Wegener 
theory that "it, nevertheless, constitutes the only plausible 
working hypothesis upon which the historical plant geogra- 
pher may base his conclusions" (463). As recently as 1950 
the British Association for the Advancement of Science di- 
vided about equally, by vote, for and against the Wegener 
theory (351). 

This continuing interest in a theory that contains so many 
and such serious difficulties is eloquent confirmation of the 
insistent pressure of the evidence in favor of polar shifts. It 
seems clear that the only reason for the continuing reluctance 
to accept polar shifts is the absence of an acceptable mecha- 
nism to account for them. The Wegener theory, despite its 
appeal, was never generally accepted by scientists, who have 
remained, as a body, until very recently, opposed to any sug- 
gestion of polar shifts. 

We must briefly consider the results of this impasse. The 
failure, over a long period of time, of successive proposals to 
account for polar change made it impossible for scientists to 
accept the field evidence, and to evaluate it on its merits. 
With no acceptable theory to account for changes in the posi- 
tions of the poles, it was natural that such changes should 
be looked upon as impossible. With each successive failure 



PAST THEORIES OF BOLAR SHIFT gl 

of a proposed theory, the reigning doctrine of the fixity of 
the poles was reinforced. As time passed this doctrine became 
deeply ingrained, so that all one needed to do to be labelled 
a crank was to suggest the possibility of polar changes. 

There have been two principal consequences of this en- 
thronement of doctrine. In the first place, the evidence 
amassed by those who had been led to attack it was quietly 
put aside. A part of the evidence was ingeniously explained 
away; most of it was simply ignored. The volumes contain- 
ing it slept on the back shelves, or even in the storage rooms, 
of the libraries, gathering dust. For several years now I have 
been busy taking out and dusting off these old books, drag- 
ging the skeletons from the closets, and finding much au- 
thentic and incontrovertible evidence that changes of the 
geographical locations of the poles have occurred at com- 
paratively short intervals during at least the greater part of 
the history of the earth. 

The other consequence of the reigning dogma was the in- 
vention of theories to explain those facts that did not fit and 
could not be ignored. One such theory, already alluded to, 
was that climates were once virtually uniform from pole to 
pole; that there were mild, moist conditions enabling water 
lilies and magnolias to bloom in the long night under the 
Pole Star. No way of accounting for this was ever supported 
by a halfway reasonable display of evidence. Nevertheless, 
such was the magic of the dogma of the fixity of the poles 
that it was accepted, and is still accepted, by a considerable 
section of the scientific world. The sum total of the contra- 
dictions in this theory, and in the various theories advanced 
to explain ice ages, mountain formation, the history of conti- 
nents and ocean basins, or evolutionary theory- will appear, 
as we proceed, to be essentially the result of the impasse be- 
tween the evidence and the doctrine of the fixity of the poles. 
The necessity of reconciling the constantly accumulating 
facts in a number of fields with a basic error has produced a 
multiplicity of theories which are, in fact, a veritable cloud 
castle of conjectures, without substance. 



32 EARTH'S SHIFTING CRUST 

5. New Proposals of Polar Shift 

Since truth cannot be suppressed forever, it was inevitable 
that accumulating facts should eventually bring the polar 
issue again into the foreground. Gutenberg suggested that 
while continents cannot drift, perhaps they can creep (194: 
211). The British astronomer Gold postulated that the earth's 
wobble on its axis could cause a plastic readjustment of its 
mantle sufficient to move the poles 90 degrees in a million 
years (176). The French geographer Jacques Blanchard sug- 
gested the possibility of extensive polar changes due to more 
pronounced wobbling of the earth in the past (38). Ting Ying 
H. Ma, of Formosa, raised the idea of a combination of conti- 
nental drift with displacement of the outer shells of the 
earth (285-290). Bain thought of displacements of the crust 
to account for facts of ancient plant geography and fossil soils 
and suggested a mechanism to try to account for them (18). 
Pauly (342) revived the suggestion made by Eddington (124) 
that the earth's crust may have been displaced by the effects of 
tidal friction. Kelly and Dachille, in a provocative work on 
collision geology entitled Target Earth, offered the hypothesis 
of displacements of the earth's crust as the result of collisions 
with planetoids (248). 

The most important recent contribution to the controversy 
has certainly been the evidence produced by geophysicists in- 
vestigating terrestrial magnetism. This new evidence is so im- 
pressive that it has brought about a reversal of opinion in high 
geological quarters on the question of the permanence of the 
poles. One of the leading specialists in this field, Dr. J. W. 
Graham, has recently remarked: 

. . . Within the past couple of years there have appeared a num- 
ber of serious papers dealing with the subject of polar wanderings by 
which is meant a shift of the geographic features of the earth's surface 
with respect to the axis of spin. Classical geophysical treatments of 
the type pioneered by Sir George H. Darwin early in this century 
have been re-examined in the light of our more recent knowledge of 



PAST THEORIES OF POLAR SHIFT gj 

the earth and its properties, and the conclusion is reached that, 
whereas polar wandering was formerly considered impossible, it now 
seems to some, at least, inevitable. These re-examinations were in- 
spired by deductions based on the rock magnetism studies of the past 
few years (428:86). 

In 1954 the results of one of these studies were made pub- 
lic by the British scientists Clegg, Almond, and Stubbs. They 
found impressive evidence of changed directions of the earth's 
magnetic field in past periods and concluded: 

Finally, it seems therefore that the most likely explanation of the 
observed horizontal direction of magnetization of the sediments 
studied is that the whole land mass which now constitutes England 
has rotated clockwise through 34 relative to the earth's geographical 
axis. . . . 

If such a rotation of England occurred, it could have been a local 
movement of a part only of the earth's crust, or alternately, the earth's 
mantle could have moved as a rigid whole relative to the geographical 
poles. The first hypothesis would consider the rotation either as a 
purely local movement or as part of a drift of large continental land 
masses. The second would adduce pole wandering as the operative 
mechanism. . . . (81:596). 

Many speculations regarding polar changes are being put 
forward at the present time without suggesting any mecha- 
nism. Thus, in recent months Soviet scientists writing for the 
newspaper Red Star had the North Pole situated at 55 N. 
Lat. 60,000,000 years ago, and in the Pacific to the southwest 
of Southern California 300,000,000 years ago, while in this 
country Munk and Revelle suggested that the South Pole 
was once over Africa (315). 

Needless to say, none of these concepts has been brought 
forward without evidence. The evidence is converging from 
many directions, with an effect of the confluence of many 
rivers into one mighty torrent. The summary of the evidence 
is the business of the following chapters. 



II : THE ICE AGES 



The evidence for displacements of the earth's crust is, as I 
have said, scattered over many parts of the earth, and comes 
from several fields of science. No other field, however, fur- 
nishes so dramatic a confirmation of it as glacial geology. 
Much new evidence has recently become available to supple- 
ment the older data relating to ice ages. 



/. The Failure of the Older Theories 

A little more than a hundred years ago people were aston- 
ished at the suggestion that great ice sheets, as much as a 
mile thick, had once lain over the temperate lands of North 
America and Europe. Many ridiculed the idea, as happens 
with new ideas in every age, and sought to discredit the evi- 
dence produced in favor of it. Eventually the facts were estab- 
lished regarding an ice age in Europe and in North America. 
People later accepted the idea of not one but a series of ice 
ages. As time went on evidences were found of ice ages on 
all the continents, even in the tropics. It was found that ice 
sheets had once covered vast areas of tropical India and equa- 
torial Africa. 

From the beginning, geologists devoted much attention to 
the possible cause of such great changes in the climate. One 
theory after another was proposed, but, as the information 
available gradually increased, each theory in turn was found 
to be in conflict with the facts, and as a consequence had to 
be discarded. In 1929, Coleman, one of the leading author- 
ities on the ice ages, wrote: 

Scores of methods of accounting for ice ages have been proposed, 
and probably no other geological problem has been so seriously dis- 
cussed, not only by glaciologists, but by meteorologists and biologists; 



THEICEAGES 35 

yet no theory is generally accepted. The opinions of those who have 
written on the subject are hopelessly in contradiction with one 
another, and good authorities are arrayed on opposite . sides. . . . 
(87:246). 

Recent writers, such as Daly (98:257), Umbgrove (429:285), 
and Gutenberg (194:205), agree that the situation described 
by Coleman is essentially unchanged. In January, 1953, Pro- 
fessor J. K. Charlesworth, of Queen's University, Belfast, 
expressed the opinion that 

The cause of all these changes, one of the greatest riddles in geolog- 
ical history, remains unsolved; despite the endeavors of generations of 
astronomers, biologists, geologists, meteorologists and physicists, it 
still eludes us (75:3). 

A volume on climatic change, edited by Dr. Harlow 
Shapley (375), while introducing minor refinements in var- 
ious theories, in no way modifies the general effect, which is 
that down to the present time the theorizing about the causes 
of ice ages has led nowhere. 



2. The Misplaced Icecaps 

One problem that writers on the ice ages have attempted to 
solve, sometimes in rather fantastic ways, but without suc- 
cess, is that of the wrong location of the great icecaps of the 
past. These icecaps have refused to have anything to do with 
the polar areas of the present day, except in a quite inci- 
dental fashion. 

Originally it was thought that in glacial periods the ice- 
caps would fan out from the poles, but then it appeared that 
none of them did so, except the ones that have existed in 
Antarctica. Coleman drew attention to the essential facts, as 
follows: 

In early times it was supposed that during the glacial period a vast 
ice cap radiated from the North Pole, extending varying distances 
southward over seas and continents. It was presently found, however, 
that some northern countries were never covered by ice, and that in 



j6 EARTH'S SHIFTING CRUST 

reality there were several more or less distinct ice sheets starting from 
local centers, and expanding in all directions, north as well as east 
and west and south. It was found, too, that these ice sheets were dis- 
tributed in what seemed a capricious manner. Siberia, now including 
some of the coldest parts of the world, was not covered, and the same 
was true of most of Alaska, and the Yukon Territory in Canada; 
while northern Europe, with its relatively mild climate, was buried 
under ice as far south as London and Berlin; and most of Canada 
and the United States were covered, the ice reaching as far south as 
Cincinnati in the Mississippi Valley (87:7-9). 

With regard to an earlier age (the Permo-Carboniferous), 
Coleman emphasized that the locations of the icecaps were 
even further out of line: 

Unless the continents have shifted their positions since that time, 
the Permo-Carboniferous glaciation occurred chiefly in what is now 
the southern temperate zone, and did not reach the arctic regions at 
all (87:90). 

He is much upset by the fact that this ice age apparently did 
not affect Europe: 

Unless European geologists have overlooked evidence of glaciation 
at the end of the Carboniferous or at the beginning of the Permian, 
the continent escaped the worst of the glaciation that had such over- 
whelming effects on other parts of the world. A reason for this exemp- 
tion is not easily found (87:96). 

One of the most extraordinary cases is that of the great ice 
sheet that covered most of India in this period. Geologists are 
able to tell from a careful study of the glacial evidences in 
what direction an ice sheet moved, and in this case the ice 
sheet moved northward from an ice center in southern India 
for a distance of 1,100 miles. Coleman comments on this as 
follows: 

Now, an ice sheet on level ground, as it seems to have been in 
India, must necessarily extend in all directions, since it is not the 
slope of the surface it rests on that sets it in motion, but the thickness 
of the ice towards the central parts. . . . 

The Indian ice sheet should push southward as well as northward. 
Did it really push as far to the south of Lat. 17 as to the north? It 



THEICEAGES 37 

extended 1100 miles to the Salt Range in the north. If it extended the 
same distance to the south it would reach the equator (87:110-11). 

The great South African geologist A. L. du Toit pointed 
out that the icecaps of all geological periods in the Southern 
Hemisphere were eccentric as regards the South Pole, just 
as the Pleistocene icecaps were eccentric with regard to the 
North Pole (87:262). Isn't it extraordinary that the Antarctic 
icecap, which we can actually see because it now exists, is the 
only one of all these icecaps that is found in the polar zone, 
where it ought to be? 

Dr. George W. Bain, a contemporary writer to whom I 
shall refer again, has pointed out a very interesting feature 
of the great icecap that existed in the Permo-Carboniferous 
Period right in the center of tropical Africa in the Congo. 
He has observed that the icecap, apparently, was asymmetric 
in shape: it spread from its center of origin much farther in 
one direction than in another (18:46). This is reconcilable 
with our theory, which depends upon the asymmetry of ice- 
caps. It seems that this African ice sheet reached the present 
equator. 

Coleman, who did a great deal of field work in Africa and 
India, studying the evidences of the ice ages there, writes in- 
terestingly of his experiences in finding the signs of intense 
cold in areas where he had to toil in the blazing heat of the 
tropical sun: 

On a hot evening in early winter two and a half degrees within the 
torrid zone amid tropical surroundings it was very hard to imagine 
the region as covered for thousands of years with thousands of feet 
of ice. The contrast of the present with the past was astounding, and 
it was easy to see why some of the early geologists fought so long 
against the idea of glaciation in India at the end of the Carboniferous 

(87:108). 

Some hours of scrambling and hammering under the intense 
African sun, in lat. 27 5', without a drop of water, while collecting 
striated stones and a slab of polished floor of slate, provided a most 
impressive contrast between the present and the past, for though 
August 27th is still early Spring, the heat is fully equal to that of a 



38 EARTH'S SHIFTING CRUST 

sunny August day in North America. The dry, wilting glare and 
perspiration made the thought of an ice sheet thousands of feet thick 
at that very spot most incredible, but most alluring (87:124). 

When these facts were established, geologists sought to ex- 
plain them by assuming that, at periods when these areas 
were glaciated, they were elevated much higher above sea 
level than they are now. Theoretically, even an area near 
the equator, if elevated several miles above sea level, would 
be cold enough for an ice sheet. What made the theory plausi- 
ble was the well-known fact that the elevations of all the 
lands of the globe have changed repeatedly and drastically 
during the course of geological history. Unfortunately for 
those who tried to explain the misplaced icecaps in this way, 
however, Coleman showed that they reached sea level, within 
the tropics, on three continents: Asia, Africa, and Australia 
(87:129, 134, 140, 168, 183). At the same time, W. J. Hum- 
phreys, in his examination of the meteorological factors of 
glaciation, made the point that high elevation means less 
moisture in the air, as well as lowered temperature, and is 
therefore unfavorable for the accumulation of great icecaps 
(232:612-13). 



5. World-wide Phases of Cold Weather 

A widely accepted assumption with which contemporary 
geologists approach the question of ice ages is that the latter 
occurred as the result of a lowering of the average tempera- 
ture of the whole surface of the earth at the same time. This 
assumption has forced them to look for a cause of glacial 
periods only in such possible factors as could operate to cool 
the whole surface of the earth at once. It has also compelled 
them to maintain the view that glacial periods have always 
been simultaneous in the Northern and Southern Hemi- 
spheres. 

It is remarkable that this assumption has been maintained 
over a long period of time despite the fact that it is in sharp 



THEICEAGES 39 

conflict with basic principles of physics in the field of meteor- 
ology. The basic conflict was brought to the attention of 
science at least seventy years ago; it has never been resolved. 
It consists essentially of the fact that glacial periods were 
periods of heavier rainfall in areas outside the regions of the 
ice sheets, so that this, together with the deep accumulations 
of ice in the great ice sheets, must have involved a higher 
average rate of precipitation during ice ages. There is a great 
deal of geological evidence in support of this. Only recently, 
for example, Davies has discussed the so-called "pluvial" 
periods in Africa, and has correlated them with the Pleisto- 
cene glacial periods (107). 

Now, meteorologists point out that if precipitation is to be 
increased, there has to be a greater supply of moisture in the 
air. The only possible way of increasing the amount of 
moisture in the air is to raise the temperature of the air. 
It would seem, therefore, that to get an ice age one would 
have to raise, rather than lower, the average temperature. 
This essential fact of physics was pointed out as long ago as 
1892 by Sir Robert Ball, who quoted an earlier remark by 
Tyndall: 

. . . Professor Tyndall has remarked that the heat that would be 
required to evaporate enough water to form a glacier would be suffi- 
cient to fuse and transform into glowing molten liquid a stream of 
cast iron five times as heavy as the glacier itself (20:108). 

William Lee Stokes has again called attention to this un- 
solved problem in his recent article entitled "Another Look 
at the Ice Age": 

Lowering temperatures and increased precipitation are considered 
to have existed side by side on a world-wide scale and over a long 
period in apparent defiance of sound climatological theory. Among 
the many quotations that could be cited reflecting the need for a 
more comprehensive explanation of this difficulty the following seems 
typical. 

"In the Arequipa region [of Peru], as in many others in both hemi- 
spheres where Pleistocene conditions have been studied, this period 
appears to have been characterized by increased precipitation as well 



40 EARTH'S SHIFTING CRUST 

as lowered temperatures. If, however, precipitation was then greater 
over certain areas of the earth's surface than it is at present, a corol- 
lary seems to be implied that over other large areas evaporation was 
greater than normal to supply increased precipitation, and hence in 
these latter areas the climate was warmer than normal. This seems at 
first to be an astonishing conclusion. . . . We might propose the 
hypothesis that climatic conditions were far from steady in any one 
area, but were subject to large shifts, and that intervals of ameliorated 
conditions in some regions coincided with increased severity in others. 
The Pleistocene, then, may have been a period of sharper contrasts 
of climate and of shifting climates rather than a period of greater 
cold" (405:815-16). 

From a number of points of view, the foregoing passage is 
extremely remarkable. Stokes recognizes the fact that the 
basic assumption of contemporary geologists regarding the 
glacial periods is in conflict with the laws of physics. Then, in 
the passage he quotes, he draws attention to the implications, 
which seem to point directly to crust displacement, for in 
what other way can we explain how one part of the earth's 
surface was colder and another, at the same time, warmer 
than at present? 

One of the arguments that is advanced in support of the 
assumption of world-wide periods of colder weather (which 
remains the generally accepted assumption of glaciologists) 
has its basis in geological evidence purporting to prove that 
ice ages occurred simultaneously in both hemispheres. A 
decade ago, however, Kroeber pointed to the essential weak- 
ness of this geological evidence, when he showed the difficulty 
of correlating stratified deposits of different areas with each 
other: 

. . . There is plenty of geologic evidence, in many parts of the 
earth, of changes of climates, especially between wet and dry areas; 
and some of these happened in the Pleistocene. But the correlation of 
such changes as they occurred in widely separated regions, and espe- 
cially as between permanently ice-free and glaciated areas, is an intri- 
cate, tricky, and highly technical matter, on which the anthropological 
student must take the word of geologists and climatologists, and these 
are by no means in agreement. They may be reasonably sure of one 
series of climatic successions in one region, and of another in a second 



THE ICE AGES 41 

or third region; but there may be little direct evidence on the corre- 
spondence of the several series of regional stages, the identification of 
which then remains speculative (257:650). 

At the time that Kroeber remarked on the difficulty of 
correlating climatic changes in different parts of the world, 
we were not yet in possession of the data recently provided by 
the new techniques of radiocarbon and ionium dating, which 
will be discussed below. The effect of the new data has been 
to shorten very greatly our estimate of the duration of the 
last North American ice age. This estimate has been reduced, 
in the last few years, from about 150,000 years to about 
25,000 years, or by five sixths. Now, if we adopt the view that 
ancient glaciations, of which we know little, may reasonably 
be considered to have been the results of the same causes 
that brought about the North American ice age, then we 
must grant that they, too, were of short duration. But if this 
is true, how is it possible to establish the fact that they were 
contemporary in the two hemispheres? A geological period 
has a duration of millions of years. An ice age in Europe and 
one in Australia might both be, for example, of Eocene age, 
but the Eocene Epoch is estimated to have lasted about 15,- 
000,000 years. We can discriminate roughly between strata 
dating from the early, middle, or late Eocene, but we have no 
way of pinpointing the date of any event in the Eocene. Even 
with the new techniques of radiodating now being applied 
to the older rocks, it is possible to determine dates only to 
within a margin of error of about a million years. How, then, 
is it possible to determine that an ice sheet in one hemisphere 
was really contemporary with an ice sheet or an ice age in 
the other? 

The attempt to maintain the assumption of the simultane- 
ousness of glaciations for the older geological periods is mani- 
festly absurd. I shall show in what follows that it is equally 
absurd for the recent geological time. It is my impression 
that the material evidence for the assumption was never im- 
pressive, and that the assumption was never derived em- 
pirically from the evidence but was borrowed a priori from 



4* EARTH'S SHIFTING CRUST 

the parent assumption, that is, the assumption of the lower- 
ing of global temperatures during ice ages, which assumption 
is, as already pointed out, in conflict with the laws of physics. 
If it is true that the fundamental assumption underlying 
most of the theories produced to explain ice ages is in error, 
we should expect that these theories, despite their many 
differences, would have a common quality of futility, and so 
it turns out. It is interesting to list the kinds of hypothetical 
causes that have been suggested to explain ice ages on the 
assumption of a world-wide lowering of temperature. They 
are as follows: 

a. Variations in the quantity of particle emission and of 
the radiant heat given off by the sun. 

b. Interception of part of the sun's radiation by clouds 
of interstellar gas or dust. 

c. Variations in the heat of space; that is, the temperature 
of particles floating in space which, entering the earth's 
atmosphere, might affect its temperature. 

d. Variations in the quantities of dust particles in the at- 
mosphere, from volcanic eruptions or other causes, or 
variations in proportion of carbon dioxide in the at- 
mosphere. 

The objections to these suggestions are all very cogent. So 
far as the variation of the sun's radiation is concerned, it is 
known that it varies slightly over short periods, but there is 
no evidence that it has ever varied enough, or for a long 
enough time, to cause an ice age. Evidence for the second and 
third suggestions is entirely lacking. The fourth suggestion is 
deprived of value because, on the one hand, no causes can 
be suggested for long-term changes in the number of erup- 
tions or in the atmospheric proportion of carbon dioxide, 
and, on the other, there is insufficient evidence to show that 
the changes ever occurred. 

I should make one reservation with regard to the fourth 
suggestion. There is one event that would provide an ade- 
quate cause for an increase in the atmosphere of both vol- 



THE ICE AGES 43 

canic dust and carbon dioxide, and that is a displacement of 
the crust. The extremely far-reaching consequences of a dis- 
placement of the crust with respect to atmospheric condi- 
tions, and the importance of the atmospheric effects of a 
displacement for other questions, will be discussed in Chap- 
ters VII and VIII. 

The theories listed above were attacked by Coleman, who 
complained that they were entirely intangible and unprov- 
able. He said: 

Such vague and accidental causes for climatic change should be 
appealed to only as a last resort unless positive proof some time be- 
comes available showing that an event of the kind actually took 
place (87:282). 

Another group of theories attempts to explain ice ages as 
the results of changes in the positions of the earth and the 
sun* These are of two kinds: changes in the distance between 
the earth and the sun at particular times because of changes 
in the shape of the earth's orbit, and changes in the angle of 
inclination of the earth's axis, which occur regularly as the 
result of precession. The argument that precession was the 
cause of ice ages was advanced by Drayson in the last century 
(117). The argument based on these astronomical changes 
has been brought up to date in the recent work of Brouwer 
and Van Woerkom (375: 147-58) and Emiliani (132). It now 
seems that these astronomical changes may produce cyclical 
changes in the distribution of the sun's heat, and perhaps in 
the amount of the sun's heat retained by the earth, but it is 
agreed, by Emiliani and others, that by itself the insolation 
curve or net temperature difference would not be sufficient 
to cause an ice age without the operation of other factors, 
and so Emiliani suggests that perhaps changes in elevation 
coinciding with the cool phases of the insolation curve may 
have caused the Pleistocene ice ages. One weakness of this 
suggestion is, of course, the necessity to suppose two inde- 
pendent causes for ice ages. 

There is another objection to be advanced against all 



44 EARTH'S SHIFTING CRUST 

theories supposing a general fall of world temperatures during 
the ice ages. We have seen that ice ages existed in the tropics 
and that great icecaps covered vast areas on and near the 
equator. This happened not once, but several times. The 
question is, if the temperature of the whole earth fell enough 
to permit ice sheets a mile thick to develop on the equator, 
just where did the fauna and flora go for refuge? How did 
they survive? How did the reef corals, which require a mini- 
mum sea- water temperature of 68 F. throughout the year, 
manage to survive? We know that the reef corals, for ex- 
ample, existed long before the period of the tropical ice 
sheets. Furthermore, we know that the great forests of the 
Carboniferous Period, which gave us most of our coal, lived 
both earlier than and contemporarily with the glaciations of 
Africa and India, though in different places. Obviously, this 
would have been impossible if the temperature of the whole 
earth had been simultaneously reduced, for the equatorial 
zone itself would have been uninhabitable while all other 
areas were still colder. It is small wonder that W. B. Wright 
insisted, over a quarter of a century ago, that the Permo- 
Carboniferous ice sheets in Africa and India were proof of a 
shift of the poles (461). 



4. The New Evidence of Radiocarbon Dating 

The problem of the causes of ice ages has been still further 
complicated by a recent revolution in our methods of dating 
geological events. In the course of the last ten years all of 
our ideas regarding the dating of the recent ice ages, their 
durations, and the speed of growth and disappearance of the 
great ice sheets have been transformed. This is altogether the 
most important new development in the sciences of the earth. 
The repercussions in many directions are most remarkable. 
In order to get an idea of the extent of the change, let us 
see what the situation was only ten years ago. As everybody is 
aware, geologists are used to thinking in terms of millions of 



THEICEAGES 45 

years. To a geologist a period of 1,000,000 years has come 
to mean almost nothing at all. He is actually used to thinking 
that events that took place somewhere within the same 20,- 
000,000-year period were roughly contemporaneous. As to 
the ice ages, the older ones were simply thrown into one of 
these long geological periods, but there was no way to de- 
termine their durations (except very roughly), their speeds 
of development, or precisely when they happened. It was 
convenient to assume that they had endured for hundreds of 
thousands or for millions of years, though no real evidence 
of this existed. A good instance is that of the Antarctic ice- 
cap, of which we shall hear more below. 

So far as the most recent division of geologic time, the 
Pleistocene, was concerned, geologists, with much more evi- 
dence to work from, saw that there had been at least four ice 
ages in a period of about 1,000,000 years. They consequently 
proposed the idea that the Pleistocene was not at all like 
previous periods. It was exceptional, because it had so many 
ice ages. They may have been misled by failure to take suffi- 
cient account of the fact that glacial evidence is very easily 
destroyed, and that, as we go further back into geological 
history, the mathematical chances of finding evidences of 
glaciation, never very good, decrease by geometrical progres- 
sion. 

Down to ten years ago and, indeed, until 1951 it was the 
considered judgment of geologists that the last ice age in 
North America, which they refer to as the Wisconsin glacia- 
tion, began about 150,000 years ago, and ended about 30,000 
years ago. 

This opinion appeared to be based upon strong evidence. 
The estimates of the date of the end of the ice age were sup- 
ported by the careful counting of clay varves (6) and by 
numerous seemingly reliable estimates of the age of Niagara 
Falls. As a consequence, experts were contemptuous of all 
those who, for one reason or another, attempted to argue that 
the ice age was more recent. One of these was Drayson, whose 
theory called for a very recent ice age. His followers produced 



46 EARTH'S SHIFTING CRUST 

much evidence, but it was ignored. When the Swedish scien* 
tist Gerard de Geer established by clay varve counting that 
the ice sheet was withdrawing from Sweden as recently as 
13,000 years ago, the implications were not really accepted, 
nor were his results popularly known. Books continued to ap- 
pear, even thirty years afterwards, with the original estimates 
of the age of the icecap. 

Then, following World War II, nuclear physics made pos- 
sible the development of new techniques for dating geolog- 
ical events. One of these was radiocarbon dating. 

The method of radiocarbon dating was developed by 
Willard F. Libby, nuclear physicist of the University of Chi- 
cago, now a member of the United States Atomic Energy 
Commission. It uses an isotope of carbon (Carbon 14) which 
has a "half-life" of about 5,568 years (115:75). A "half-life" 
is the period during which a radioactive substance loses half 
its mass by radiation. Among the very numerous artificial 
radioactive elements created in nuclear explosions some have 
half-lives of millionths of seconds; others, occurring in na- 
ture, have half-lives of millions of years. For geological dating 
it is necessary to have radioactive elements that diminish sig- 
nificantly during the periods that have to be studied, and 
that occur in nature. 

Since radiocarbon exists in nature, and has a relatively 
short half-life, the quantity of it in any substance containing 
organic carbon will decline perceptibly in periods of a few 
centuries. By finding out how much carbon was contained 
originally in the specimen and then measuring what still re- 
mains, the date can be found to within a small margin of 
error. 

When this method was first developed by Libby, it could 
date anything containing carbon of organic origin back to 
about 20,000 years ago. Since then the method has been im- 
proved, through the efforts of many scientists, and its range 
has been nearly doubled. 

The first major result of the radiocarbon method was the 



THEICEAGES 47 

revelation that the last North American ice sheet had indeed 
disappeared at a very recent date. Tests made in 1951 showed 
that it was still advancing in Wisconsin as recently as 11,000 
years ago (272:105); later tests indicated that the maximum 
of the ice advance may have been a thousand years later than 
that. When these dates are compared with other dates show- 
ing the establishment of a climate like the present one in 
North America, it seems that most of the retreat and disap- 
pearance of the great continental icecap (with its 4,000,000 
square miles of ice) can have taken little more than two or 
three thousand years. 

What is the significance of this new discovery, besides 
showing how wrong the geologists had been before? The fact 
is that so sudden a disappearance of a continental icecap 
raises fundamental questions. It endangers some basic as- 
sumptions of geological science. What has become of those 
gradually acting forces that were supposed to govern glacia- 
tion as well as all other geological processes? What factor can 
account for this astonishing rate of change? It seems self- 
evident that no astronomical change and no subcrustal 
change deep in the earth can occur at that rate. 

When this discovery was made, I expected that the next 
revelation must be to the effect that the Wisconsin ice sheet 
had had its origin at a much more recent time than was sus- 
pected, and that the whole length of the glacial period was 
but a fraction of the former estimates. I had a while to wait, 
because radiocarbon dating in 1951 was not able to answer 
the question. By 1954, however, the technique had been im- 
proved so that it could determine dates as far back as 30,000 
years ago. Many datings of the earlier phases of the Wisconsin 
glaciation were made, and Horberg, who assembled them, 
reached the conclusion that the icecap, instead of being 150,- 
ooo years old, had appeared in Ohio only 25,000 years ago 
(222:278-86). This conclusion has been so great a shock to 
contemporary geology that some writers have sought to evade 
the clear implications, by questioning the radiocarbon meth- 



48 EARTH'S SHIFTING CRUST 

od. Horberg betrays evidence of the intensity of the shock 
to accepted beliefs when he says that the results of the evi- 
dence are so appalling from the standpoint of accepted theory 
that it may be necessary either to abandon the concept of 
gradual change in geology or to question the radiocarbon 
method. 

In this book I am not going to question the general re- 
liability of the radiocarbon method. I intend merely to ques- 
tion the theories with which the new evidence conflicts. Dr. 
Horberg says that the necessity to compress all the known 
stages of the Wisconsin glaciation into the incredibly short 
period of barely 15,000 or 20,000 years involves an accel- 
eration of geological processes snowfall, rainfall, erosion, 
sedimentation, and melting that seems to challenge the prin- 
ciple laid down by the founder of modern geology, Sir 
Charles Lyell, over a century ago. Lyell's principle, called 
"uniformitarianism," was that geological processes have al- 
ways gone on about as they are going on now. 

The Wisconsin icecap went through a number of oscilla- 
tions, warm periods of ice recession alternating with cold 
periods of ice readvance. Horberg is at a loss to see what 
could cause them to occur at the velocity required by the 
radiocarbon dates. Allowing for extra time for ice growth be- 
fore the evidence of massive glaciation in Ohio 25,000 years 
ago, Horberg manages to expand this 15,000 years to 25,000 
for the duration of the glacier, but this does not solve his 
problem. Even so, the radiocarbon dates seem to require an 
annual movement of the ice front of 2,005 feet, "two to nine 
times greater than the rate indicated by varves and annual 
moraines" (222:283). 

The fact that these new facts call into question some basic 
ideas in geology is recognized by Horberg: 

Probably only time and the progress of future studies can tell 
whether we cling too tenaciously to the uniformitarian principle in 
our unwillingness to accept fully the rapid glacier fluctuations evi- 
denced by radiocarbon dating (222:285). 



THEICEAGES 49 

Recent geological literature shows that a rather desperate 
effort is being made to blur the significance of the new data. 
We will return to this question later. Here I would like to 
suggest some far-reaching implications of these facts. We have 
seen an ice sheet appear and disappear ingeologically speak- 
inga twinkling of an eye. There are three deductions to be 
made: 

a. Any theory of ice ages must give a cause that can operate 
so fast. 

b. If the last icecap in North America appeared and disap- 
peared in 25,000 years, we cannot assume that the an- 
cient icecaps lasted for longer periods. 

c. If other geological processes are correlated with ice ages, 
then their tempo must also have been faster than we 
have supposed, and a cause must be found for their 
accelerated tempo. 

In later chapters we shall see that a displacement of the 
crust must accelerate these geological processes. 



5. The New Evidence from Antarctica 

Another kind of radioelement dating has provided us with 
new data as revolutionary in their implications as the data 
produced by the radiocarbon method. This is referred to as 
the radioelement inequilibrium method or (for short) the 
ionium method of dating. It was developed by Dr. W. D. 
Urry and Dr. C. S. Piggott, of the Carnegie Institution of 
Washington, before World War II (439, 440). In recent years 
it has been widely applied in oceanographic research by both 
American and foreign scientists. 

The ionium method is used with sea sediments. It is based 
upon three radioactive elements, uranium, ionium, and 
radium, which are found in sea water and in sea sediments, 
and that decay at different rates. As the result of the different 



50 EARTH'S SHIFTING CRUST 

rates of decay, the proportions of the three elements in a 
sample of sediment change with time, and thus it is possible, 
by measuring the remnant quantities of the three elements, 
to date the samples.The samples are obtained by taking long 
cores from the bottom of the sea. A core is obtained by lower- 
ing a coring tube from a ship. It pierces the bottom sediments 
and obtains a cross section of them. The ionium method per- 
mits dating back as far as about 300,000 years. 

Among the materials first dated by Urry's method were 
some long cores that had been taken from the bottom of the 
Ross Sea in Antarctica by Dr. Jack Hough during the Byrd 
expedition of 1947-48. These cores showed alternations in 
types of sediment. There was coarse glacial sediment, as was 
expected, and finer sediment of semiglacial type, but there 
were also layers of fine sediment typical of temperate climates. 
It was the sort of sediment that is carried down by rivers from 
ice-free continents. Here was a first surprise, then. Temper- 
ate conditions had evidently prevailed in Antarctica in the 
not distant past. The sediment indicated that not less than 
four times during the Pleistocene Epoch, or during the last 
million years, had Antarctica enjoyed temperate climates. (See 
Figure XI, p. 306.) 

Then, when this material was dated by Dr. Urry, it became 
plain that the numerous climatic changes had occurred at 
very short intervals. Moreover, it appeared that the last ice 
age in Antarctica started only a few thousand years ago. 
Hough wrote: 

The log of core N-5 shows glacial marine sediment from the pres- 
ent to 6,000 years ago. From 6,000 to 15,000 years ago the sediment is 
fine-grained with the exception of one granule at about 12,000 years 
ago. This suggests an absence of ice from the area during that period, 
except perhaps for a stray iceberg 12,000 years ago. Glacial marine 
sediment occurs from 15,000 to 29,500 years ago; then there is a zone 
of fine-grained sediment from 30,000 to 40,000 years ago, again sug- 
gesting an absence of ice from the sea. From 40,000 to 133,500 years 
ago there is glacial marine material, divided into two zones of coarse- 
and two zones of medium-grained texture. 



THE ICE AGES 51 

The period 133,000-173,000 years ago is represented by fine-grained 
sediment, approximately half of which is finely laminated. Isolated 
pebbles occur at 140,000, 147,000 and 156,000 years. This zone is in- 
terpreted as recording a time during which the sea at this station was 
ice free, except for a few stray bergs, when the three pebbles were 
deposited. The laminated sediment may represent seasonal outwash 
from glacial ice on the Antarctic continent. 

Glacial marine sediment is present from 173,000 to 350,000 years 
ago, with some variation in the texture. Laminated fine-grained sedi- 
ment from 350,000 to 420,000 years ago may again represent rhythmic 
deposition of outwash from Antarctica in an ice free sea. The bottom 
part of the core contains glacial marine sediment dated from 420,000 
to 460,000 years by extra-polation of the time scale from the younger 
part of the core (225:257-59). 

It should be realized that the Ross Sea, from which these 
cores were taken, is a great triangular wedge driven right into 
the heart of the continent of Antarctica, to within about 
eight hundred miles of the pole. It follows that, when the 
shores of the Ross Sea were free of ice, and if free-flowing 
rivers were bringing down sediment from the interior, Ant- 
arctica must have been very largely an ice-free continent. 
Some of the fine sediment, it is true, does not indicate ice-free 
conditions for the whole continent, but only for the sea itself. 
The laminated sediment, consisting of distinct thin layers 
each representing the deposition of one year, suggests the 
results of a summer melting of an ice sheet not far from the 
sea, with swollen streams of melt water carrying the sedi- 
ment to the sea. Such conditions do not suggest any wide 
deglaciation of Antarctica, though they do suggest conditions 
very different from those prevailing now. On the other hand, 
unlaminated deposits of fine sediment are consistent with a 
general and even with a total deglaciation of Antarctica. So 
far as we can see, such sediment can only have been brought 
down to the sea by rivers flowing from the interior of the 
continent. The very existence of such unfrozen rivers re- 
quires the deglaciation of a part of the continent. One is free 
to assume that the deglaciation applied to only a small area, 



52 EARTH'S SHIFTING CRUST 

but there is really no good reason to adopt this assumption 
unless a cause can be shown for a local deglaciation. 1 

The importance of all this evidence is obvious when we 
realize that, as late as 1 950, there appeared to be no question 
but that the icecap in Antarctica was millions of years old. 
According to Brooks, the geologists Wright and Priestly had 
presented conclusive evidence of the beginning of the present 
icecap as far back as the beginning of the Tertiary Period 
(52:239), some 60 or 80 million years ago. Now we have evi- 
dence of several periods of semiglacial or nonglacial condi- 
tions in Antarctica in the Pleistocene Epoch alone. This is 
sufficient to show us how little reliance can be placed upon the 
estimated durations of hundreds of thousands or millions of 
years for the glacial periods of the remote past. 

We must realize, however, that the date found by Urry for 
the beginning of the deposition of glacial sediment on the 

1 An astonishing bit of evidence suggesting the idea of a temperate age in Ant- 
arctica has been produced by Arlington H. Mallery, cartographer and archae- 
ologist. Mr. Mallery solved the projection of an ancient map compiled in the 
sixteenth century by the Turkish geographer Piri Reis, from maps one of which 
is said to have been in the possession of Columbus, and the others of which 
were said by Piri Reis to have been preserved in the East since the time of 
Alexander the Great (who may have discovered them in Egypt). The projection 
had long baffled scientists, including the explorer-scientist Nordenskjold, who 
had spent seventeen years trying to solve it. When Mr. Mallery solved the pro- 
jection he found that the map showed all the coasts of South America, a great 
part of the coast of Antarctica, including Queen Maud Land and the Palmer 
Peninsula, and Greenland and Alaska. It appeared that the mapping of Antarc- 
tica had actually been done when the land was ice- free before the icecap ap- 
peared. There was no indication as to what ancient people could have made 
the map, but Mr. Mallery concluded that the information on the map was at 
least five thousand years old, and perhaps much o^der. The topographic fea- 
tures on the map of Queen Maud Land corresponded remarkably to the fea- 
tures deduced from seismic profiles made during one of the recent Antarctic 
expeditions of the Navy. Mr. Mallery's statements were confirmed and sup- 
ported by Mr. M. I. Walters, who, as a member of the Hydrographic Office, had 
checked the map in detail, and by Father Daniel Linehan, Director of the 
Weston Observatory of Boston College, who checked the seismic profile made 
by the Navy against the data on the map. Mr. Mallery's findings were presented 
in a radio broadcast by the Georgetown University Forum, Washington, D.C., 
in August, 1956. A verbatim report of the broadcast, with reproductions of the 
map, may be obtained from the Forum. 



THEICEAGES 53 

bottom of the Ross Sea 6,000 years ago is not the date of the 
beginning of the last change of climate in Antarctica. A con- 
siderable time must have elapsed between the fall of tempera- 
ture on the continent and the beginning of the deposition of 
the glacial sediment. An icecap must grow to a considerable 
thickness before it can start to move by gravity, and can start 
to throw off icebergs at the coast. Moreover, we must suppose 
that the change of climate must have been gradual at first. It 
seems reasonable, therefore, to allow a period of the order 
of about 10,000 years from the time the climate started to 
change to the time when the glacial sediment began to be 
deposited on the sea bottom. This is all the more likely since 
most of the coasts of Antarctica seem to be bounded by moun- 
tain chains, which the icecap would have to cross. 

Where do these considerations lead us? They lead us to the 
conclusion that the melting of the great icecap in North 
America about 10,000 years ago and the beginning of the 
massive advance of the Antarctic icecap may have been 
roughly contemporary; that as one icecap melted, the other 
one grew. 

Let us pause to consider the implications of this astonish- 
ing conclusion. For one thing, it is clear that no such change 
as the growth or removal of even a considerable part of a 
continental icecap covering 6,000,000 square miles of the 
earth's surface can result from purely local causes. At present 
the Antarctic icecap profoundly affects the climate of the 
whole world. The great anticyclonic winds, blowing outward 
from the continent in all directions, influence the directions 
of ocean currents, and the climates of all the lands in the 
Southern Hemisphere. The North American icecap was 
equally a factor in k world climate. If one icecap appeared 
when the other disappeared, then both of these great con- 
temporary changes of climate must be supposed to have re- 
sulted from some cause operating on the globe as a whole. 
But what kind of cause could glaciate one continent and 
deglaciate the other? It seems quite clear that only a shift of 
the crust of the earth such as would have moved America 



54 EARTH'S SHIFTING CRUST 

away from one polar zone and Antarctica toward the other 
one can adequately account for the facts. Moreover, it is true, 
as can be seen from any globe, that a movement of the crust 
sufficient to bring Hudson Bay down to its present latitude 
from the pole would at the same time account for the glacia- 
tion of all that half of Antarctica facing the Ross Sea. 

There are a number of important conclusions to be drawn 
from these Antarctic data, in addition to the remarkable con- 
firmation of a displacement of the crust. One is that the rapid 
rate of change indicated for the Wisconsin icecap may be 
typical for the whole Pleistdcene, and therefore, very likely, 
typical of older periods in the earth's history. Hardly less 
important than this is the implication to be drawn from the 
apparent fact that the ice ages, in these two instances, were 
not contemporaneous. It follows, of course, that if the ice 
ages we know most about were not contemporary in the two 
hemispheres, there is no justification for assuming that those 
we know little or nothing about were contemporary. Clearly, 
with glacial periods so short, and the tempo of change so 
rapid, there is no justification for claiming glaciation in the 
two hemispheres hundreds of millions of years ago to have 
been simultaneous. This theory, which constitutes a harmful 
dogma of contemporary science, should now be abandoned, 
and with it must go most of the current speculations about 
the causes of ice ages. 

I cannot conclude this chapter without warning the reader 
that, however clear these facts may be, there are still some 
who will insist that the Hough-Urry cores show that the re- 
cent glaciations were simultaneous in the two hemispheres. 
This argument is based on the strange period of high tempera- 
ture that followed the ice age in North America, but was 
world-wide in its effects. This warm period has been well es- 
tablished, but its cause has been unknown. The essential facts 
are given by Professor Flint: 

. . . the evidence of the fossil plants, and, in addition, several en- 
tirely independent lines of evidence, establish beyond doubt that the 
climate (with some fluctuation) reached a maximum of warmth be- 



THE ICE AGES 55 

tween 6,000 and 4,000 years ago; since then (again with minor fluctua- 
tions) it has become cooler and more moist down to the present time. 
Apparently as recently as 500 B.C. the climate was still slightly warmer 
than it is today. The warm, relatively dry interval of 2000 years' dura- 
tion has been called the Climatic Optimum. It is the outstanding 
fact of the so-called post-glacial climatic history (156:487). 

Dr. Hough attempts to identify the last warm period in 
Antarctica with this Climatic Optimum, but we have seen 
that, according to his own core, the last temperate period in 
Antarctica apparently began 15,000 years ago, and ended 
6,000 years ago, thus enduring for some 9,000 years, while 
the Climatic Optimum began 6,000 years ago, when the tem- 
perate age was drawing to a close in Antarctica, and endured 
for only 2,000 years. It seems to me, therefore, that there is 
no good reason to identify the two. 

For some time attempts were made to attack the reliability 
of the ionium method. I raised the question of these attacks 
in a conversation with Einstein and received assurance that 
in his opinion the method was reliable. Ericson and Wollin 
have recently shown that the results obtained by the ionium 
method agree very well with results achieved by other relia- 
ble means (Chapter IX). We shall have occasion to cite the 
work of Soviet scientists who appear to have used the ionium 
method successfully in the Arctic Ocean, and to have ob- 
tained results in good agreement with other methods of dat- 
ing. We shall see that they have found a warm period for the 
Arctic to correspond with the warm period indicated for Ant- 
arctica, and at about the same time, just as we should expect 
if both areas lay outside of the polar circles when the last 
North American icecap was centered at Hudson Bay. 

Volchok and Kulp have recently published the results of 
a study by which some sources of errors in the use of the ion- 
ium method for dating have been identified. Their results 
suggest that in some cases errors in dating may result from 
the use of cores that have not been continuously deposited, 
or that have been disturbed since their original deposition. 
However, in the cases^of the Ross Sea cores cited above we 



56 EARTH'S SHIFTING CRUST 

have three cores taken some distance apart that seem, never- 
theless, to agree pretty well with each other, even though 
there are evidences of some disturbance, and their evidence 
is strengthened by their agreement with the Arctic cores to 
be discussed later on. 

From our point of view, the precise accuracy of the dating 
is less important than the evidence that, in very recent time, 
there was deposition of temperate type sediment in the Ross 
Sea off the Antarctic coast. 

6. Conclusion 

It is clear that none of the great glaciations of the past can 
be explained by the theories hitherto advanced. The only 
ice age that is adequately explained is the present ice age in 
Antarctica. This is excellently explained. It exists, quite obvi- 
ously, because Antarctica is at the pole, and for no other 
reason. No variation of the sun's heat, no galactic dust, no 
volcanism, no subcrustal currents, and no arrangements of 
land elevations or sea currents account for the fact. We may 
conclude that the best theory to account for an ice age is 
that the area concerned was at a pole. We thus account for 
the Indian and African ice sheets, though the areas once occu- 
pied by them are now in the tropics. We account for all ice 
sheets of continental size in the same way. 

Stokes has provided an excellent list of specifications for a 
satisfactory ice age theory, every one of which is met by the 
assumption of crust displacements as the fundamental cause 
(405:815-16): 

a. An initiating event or condition. 

b. A mechanism for cyclic repetitions or oscillations within 
the general period of glaciation. 

c. A terminating condition or event. 

d. It should not rely upon unprovable, unobservable, or 
unpredictable conditions, when well-known or more 
simple ones will suffice. 



THE ICE AGES 57 

e. It must solve the problem of increased precipitation 
with colder climate. 

f. The facts call for a mechanism that either increases the 
precipitation or lowers the temperature very gradually 
over a period of thousands of years. 

It is evident that a displacement of the crust could initiate 
an ice age by moving a certain region into a polar zone, while 
a later displacement could end the ice age by moving the 
same area away from the polar zone. The increased precipita- 
tion and the oscillations of the borders of the ice sheets can 
be explained by the atmospheric effects that would result 
from volcanism associated with the movement of the crust. 
These effects will be discussed in later chapters. 



Ill : ANCIENT CLIMATES 



In the last chapter it was argued that the ice ages can be 
explained only by the assumption of frequent displacements 
of the earth's crust. The ice ages, however, represent only one 
side of the problem. If they are instances of extremely cold 
climates distributed in an unexplained manner on the earth's 
surface, there were also warm climates whose distribution is 
equally unexplained. 

In connection with these warm climates in the present 
polar regions, there arises a contradiction of an especially 
glaring character. On the one hand there is evidence that the 
distribution of plants and animals in the past did not, as a 
rule, follow the present arrangements of the climatic zones. 
On the other hand, the trend of the new evidence is to show 
that climatic zones have always been about as clearly dis- 
tinguished by temperature differences as they are today. This 
is in flat contradiction to the assumption, still widely held, 
that the earth, during most of geological history, did not 
possess clearly demarcated climatic zones. We are forced to 
conclude that, since many ancient plants and animals were 
not distributed according to the present climatic zones, the 
zones themselves have changed position on the earth's surface. 
This requires, as we have seen, that the surface shall have 
changed position relative to the axis of rotation. We shall 
now examine the evidence that supports this conclusion. 



/. Ages of Bloom in Antarctica 

1 have suggested that in very recent time, no more than 
10,000 years ago, a large part of Antarctica may have been 
ice-free. If this interpretation of the marine cores from the 
Ross Sea is questioned by the conservative-minded, there 



ANCIENT CLIMATES 59 

can, however, be no dispute whatever about the more distant 
past climates of Antarctica. Those who may be inclined to 
disbelieve that Antarctica could have possessed a temperate 
climate 10,000 years ago must be reminded of the evidence 
that Antarctica has many times possessed such a climate. 

So far as we know at present, the very first evidence of an 
ice age in Antarctica comes from the Eocene Epoch (52:244). 
This was barely 60,000,000 years ago. Before that, for some 
billion and a half years, there is no suggestion of polar condi- 
tions, though very many earlier ice ages existed in other parts 
of the earth. Henry, in The White Continent, cites evidence 
of the passing of long temperate ages in Antarctica. He de- 
scribes the Edsel Ford Mountains, discovered by Admiral 
Byrd in 1929. These mountains are of nonvolcanic, folded 
sedimentary rocks, the layers adding up to 15,000 feet in 
thickness. Henry suggests that they indicate long periods of 
temperate climate in Antarctica: 

The greater part of the erosion probably took place when Antarctica 
was essentially free of ice, since the structure of the rocks indicates 
strongly that the original sediment from which they were formed was 
carried by water. Such an accumulation calls for an immensely long 
period of tepid peace in the life of the rampaging planet (206:113). 

Most sedimentary rocks are laid down in the sea, formed 
of sediment brought down by rivers from near-by lands. The 
lands from which the Antarctic sediments were brought seem 
to have disappeared without a trace, but of the sea that once 
existed where there is now land we have plenty of evidence. 
Brooks remarks: 

... In the Cambrian we have evidence of a moderately warm sea 
stretching nearly or right across Antarctica, in the form of thick lime- 
stones very rich in reef-building Archaeocyathidae (52:245). 

Millions of years later, when these marine formations had 
appeared above the sea, warm climates brought forth a luxu- 
riant vegetation in Antarctica. Thus, Sir Ernest Shackleton 
is said to have found coal beds within 200 miles of the South 
Pole (71:80), and later, during the Byrd expedition of 1935, 



60 EARTH'S SHIFTING CRUST 

geologists made a rich discovery of fossils on the sides of lofty 
Mount Weaver, in Latitude 86 58' S., about the same dis- 
tance from the pole, and two miles above sea level. These 
included leaf and stem impressions, and fossilized wood. In 
1952 Dr. Lyman H. Dougherty, of the Carnegie Institution 
of Washington, completing a study of these fossils, identified 
two species of a tree fern called Glossopteris, once common 
to the other southern continents (Africa, South America, 
Australia), and a giant tree fern of another species. In addi- 
tion, he identified a fossil footprint as that of a mammallike 
reptile. Henry suggests that this may mean that Antarctica, 
during its period of intensive vegetation, was one of the most 
advanced lands of the world as to its life forms (207). 

Soviet scientists have reported finding evidences of a trop- 
ical flora in Graham Land, another part of Antarctica, dating 
from the early Tertiary Period (perhaps from the Paleocene 
or Eocene) (364:13). 

It is, then, little wonder that Priestly, in his account of his 
expedition to Antarctica, should have concluded: 

. . . There can be no doubt from what this expedition and 
other expeditions have found that several times at least during past 
ages the Antarctic has possessed a climate much more genial than that 
of England at the present day , . . (34913:210). 

Further evidence is provided by the discovery by British 
geologists of great fossil forests in Antarctica, of the same type 
that grew on the Pacific coast of the United States 20,000,000 
years ago (206:9). This, of course, shows that after the earliest 
known Antarctic glaciation in the Eocene, the continent did 
not remain glacial, but had later episodes of warm climate. 

Dr. Umbgrove adds the observation that in the Jurassic 
Period the flora of Antarctica, England, North America, and 
India had many plants in common (430:263). 

There is one group of theories to which we cannot appeal 
because of their inherent and obvious weaknesses. These 
are the theories that try to explain warm and cold periods in 
Antarctica by changes in land elevations, changes in the 



ANCIENT CLIMATES 6l 

directions of ocean currents, changes in the intensity of solar 
radiation, and the like. It is obvious, for instance, that no 
hypothetical warm currents could make possible the existence 
of warm climates in the center of the great Antarctic conti- 
nent if that continent were at the pole, and if by some miracle 
Antarctica did become warm, how possibly could forests have 
flourished there deprived of sunlight for half the year? 



2. Warm Ages in the North 

The Arctic regions have been more accessible, and conse- 
quently they have been more thoroughly explored, than the 
Antarctic. It was from them that the first evidence came 
pointing unmistakably to shifts in the geographical positions 
of the poles. Most of the theories developed by those defend- 
ing the dogma of the permanence of the poles were specially 
designed to explain these facts, or rather, as it now seems, to 
explain them away. 

One method of explaining away the evidence was to sug- 
gest that the plants and animals of past geological eras, even 
though they belonged to similar genera or families as living 
plants, and closely resembled them in structure, may have 
been adapted to very different climates. This argument often 
had effect, for no one could exclude the possibility that, in a 
long geological period, species might make successful adjust- 
ments to different climatic conditions. Where single plants 
were involved such a possibility could not be dismissed. 
Where, however, whole groups of species, whole floras and 
faunas, were involved, there was increased improbability that 
they could all have been adjusted at any one time to a radi- 
cally different environment from that in which their de- 
scendants live today. For this reason, and because the 
structure of plants has a definite relationship to conditions 
of sunlight, heat, and moisture, biologists have abandoned 
this method of explaining the facts. Dr. Barghoorn, for ex- 



62 EARTH'S SHIFTING CRUST 

ample, says that fossil plants are reliable indicators of past 

climate (375 : 237~3 8 )- 

It may be worth while to review, very briefly, some high 
points of the climatic history of the Arctic and sub-Arctic 
regions, beginning with one of the oldest periods, the Devo- 
nian, and coming down by degrees to periods nearer our 
own. (During this discussion the reader may find it helpful 
to refer to the table of geological periods, page 23.) 

The Devonian evidence is particularly rich, and includes 
both fauna and flora. Dr. Colbert, of the American Museum 
of Natural History, has pointed out that the first known 
amphibians have been found in this period in eastern Green- 
land, near the Arctic Circle, though they must have required 
a warm climate (375:256). Many species of reef corals, which 
at present require an all-year sea-water temperature of not 
less than 68 F. (102:108), have been found in Ellesmere Is- 
land, far to the north of the Arctic Circle (399:2). Devonian 
tree ferns have been found from southern Russia to Bear 
Island, in the Arctic Ocean (177:360). According to Barg- 
hoorn, assemblages of Devonian plants have been found in 
the Falkland Islands, where a cold climate now prevails, in 
Spitzbergen, and in Ellesmere Island, as well as in Asia and 
America (375:240). In view of this, he remarks: 

The known distribution of Devonian plants, especially their diversi- 
fication in high latitudes, suggests that glacial conditions did not exist 
at the poles (375:240). 

In the following period, the Carboniferous, we have evi- 
dence summed up by Alfred Russel Wallace, co-author, with 
Darwin, of the theory of evolution: 

In the Carboniferous formation we again meet with plant remains 
and beds of true coal in the Arctic regions. Lepidodendrons and 
calamites, together with large spreading ferns, are found at Spitz- 
bergen, and at Bear Island in the extreme north of Eastern Siberia; 
while marine deposits of the same age contain an abundance of large 
stony corals (446:202). 

In the Permian, following the Carboniferous, Colbert re- 
ports a find of fossil reptiles in what is now a bitterly cold 



ANCIENT CLIMATES 6j 

region: ' 'Large Permian reptiles . . . are found along the 
Dvina River of Russia, just below the Arctic Circle, at a 
North Latitude of 65 " (375:259). Dr. Colbert explains that 
these reptiles must have required a warm climate. In sum- 
ming up the problem of plant life for the many long ages 
of the Paleozoic Era, from the Devonian through the Per- 
mian, Barghoorn says that it is "one of the great enigmas" o 
science (375 : *43>- 

Coming now to the Mesozoic Era (comprising the Triassic, 
Jurassic, and Cretaceous Periods), Colbert reports that in the 
Triassic some amphibians (the Labyrinthodonts) ranged all 
the way from 40 S. Lat. to 80 N. Lat. About this time the 
warm-water Ichthyosaurus lived at Spitzbergen (375:262-64). 
For the Jurassic, Wallace reports: 

In the Jurassic Period, for example, we have proofs of a mild arctic 
climate, in the abundant plant remains of East Siberia and Amurland. 
. . . But even more remarkable are the marine remains found in 
many places in high northern latitudes, among which we may espe- 
cially mention the numerous ammonites and the vertebrae of huge 
reptiles of the genera Ichthyosaurus and Teleosaurus found in Jurassic 
deposits of the Parry Islands in 77 N. Lat. (446:202). 

For the Cretaceous Period, A. C. Seward reported in 1932 
that "the commonest Cretaceous ferns [of Greenland] are 
closely allied to species ... in the southern tropics" (373: 
363-71). Gutenberg remarks: "Thus, certain regions, such 
as Iceland or Antarctica, which are very cold now, for the late 
Paleozoic or the Mesozoic era show clear indications of what 
we would call subtropical climate today, but no trace of 
glaciation; at the same time other regions were at least tempo- 
rarily glaciated' 1 (194:195). This evidence, linked in this way 
with the problem of the ice ages we have already discussed, 
reveals the existence of a single problem. Ice ages in low 
latitudes, and warm ages near the poles, are, so to speak, the 
sides of a single coin. A successful theory must explain both 
of them. 

Following the Cretaceous, the Tertiary Period shows the 
same failure of the fauna and flora to observe our present 



64 EARTH'S SHIFTING CRUST 

climatic zones. Scott, for example, says: "The very rich floras 
from the Green River shales, from the Wilcox of the Gulf 
Coast and from the Eocene of Greenland, show that the 
climate was warmer than in the Paleocene, and much warmer 
than today" (372:103). 

In this Eocene Epoch we find evidence of warm climate in 
the north that is truly overwhelming. Captain Nares, one of 
the earlier explorers of the Arctic, described a twenty-five-foot 
seam of coal that he thought was comparable in quality to 
the best Welsh coal, containing fossils similar to the Miocene 
fossils of Spitsbergen. He saw it near Watercourse Bay, in 
northern Greenland (319:!!, 141-42). Closer examination 
revealed that it was, in reality, lignite. Nevertheless, the con- 
tained fossils clearly indicated a climate completely different 
from the present climate of northern Greenland: 

The Grinnell Land lignite indicates a thick peat moss, with prob- 
ably a small lake, with water lilies on the surface of the water, and 
reeds on the edges, and birches and poplars, and taxodias, on the 
banks, with pines, firs, spruce, elms and hazel bushes on the neighbor- 
ing hills . . . (319:11,335). 

Brooks thinks that the formation of peat bogs requires a 
rainfall of at least forty inches a year, and a mean tempera- 
ture above 32 F. (52:173). This suggests a very sharp con- 
trast with present Arctic conditions in Grinnell Land. 

DeRance and Feilden, who did the paleontological work 
for Captain Nares, also mention a Miocene tree, the swamp 
cypress, that flourished from Central Italy to 82 N. Lat., that 
is, to within five hundred miles of the pole (319:!!, 335). 
They show that the Miocene floras of Grinnell Land, Green- 
land, and Spitzbergen all required temperate climatic condi- 
tions, with plentiful moisture. They mention especially the 
water lilies of Spitzbergen, which would have required flow- 
ing water for the greater part of the year (319:!!, 336). 

In connection with the flora of Spitzbergen, and the fauna 
mentioned earlier, it should be realized that the island is in 
polar darkness for half the year. It lies on the Arctic Circle, 
as far north of Labrador as Labrador is north of Bermuda. 



Wallace describes the flora of the Miocene. He points out 
that in Asia and in North America this flora was composed 
of species that apparently required a climate similar to that 
of our southern states, yet it is also found in Greenland at 
70 N. Lat., where it contained many of the same trees that 
were then growing in Europe. He adds: 

But even farther North, in Spitsbergen, 78 and 79 N. Lat. and 
one of the most barren and inhospitable regions on the globe, an 
almost equally rich fossil flora has been discovered, including several 
of the Greenland species, and others peculiar, but mostly of the same 
genera. There seem to be no evergreens here except coniferae, one of 
which is identical with the swamp-cypress (Taxodium distichum) now 
found living in the Southern United States. There are also eleven 
pines, two Libocedrus, two Sequoias, with oaks, poplars, birches, 
planes, limes, a hazel, an ash, and a walnut; also water lilies, pond 
weeds, and an Iris altogether about a hundred species of flowering 
plants. Even in Grinnell Land, within 8i/ degrees of the pole, a 
similar flora existed . . . (446:182-84). 

It has been necessary to dwell at length on the evidence of 
the warm polar climates, because this is important for the 
discussion that follows. Too often, in theoretical discussions, 
the specific nature of the evidence tends to be lost sight of. 



3. Universal Temperate ClimatesA Fallacy 

The evidence I have presented above (and a great deal more, 
omitted for reasons of space) has long created a dilemma for 
geology. Only two practical solutions have offered themselves. 
One is to shift the crust, and the other is to suggest that 
climatic zones like the present have not always existed. It is 
often suggested that the climates have been very mild virtu- 
ally from pole to pole, at certain times. The extent to which 
this theory is still supported is eloquent evidence of the 
power of the "dogma" of the permanence of the poles. When 
one inquires as to the evidence for the existence of such 
warm, moist climates, a peculiar situation is revealed. There 
is no evidence except the fossil evidence that the theory is 



66 EARTH'S SHIFTING CRUST 

supposed to explain. Could there be a better example of 
reasoning in a circle? Colbert cites evidence that the Devo- 
nian animals were spread all over the world, and then re- 
marks that therefore ". . . it is reasonable to assume . . . 
that the Devonian Period was a time of widely spread equable 
climates, a period of uniformity over much of the earth's 
surface" (375:255). According to him, the same situation held 
true through the Paleozoic and Mesozoic, and even much 
later periods (375:268). Other paleontologists reasoned in the 
same way. Goldring, for example, remarked: "The Carbonif- 
erous plants had a world-wide distribution, suggesting rather 
uniform climatic conditions" (177:362). She drew the same 
conclusions from the world-wide distribution of Jurassic flora 
(177:363). But it is clear that when a theory has been con- 
cocted to explain a given set of facts, those facts themselves 
cannot be adduced as proof of the theory. This is circular 
reasoning. A theory must, first, be shown to be inherently 
reasonable, and then it must be supported by independent 
facts. 

Is such a theory inherently reasonable? The answer is that 
it is not. It involves, in the first place, ignoring the astro- 
nomical relations of the earth. The theory requires us to 
assume the existence of some factor powerful enough to coun- 
teract the variation of the sun's heat with latitude. As Pro- 
fessor Bain, of Amherst, has pointed out, in an article to be 
discussed further below, 

. /'. The thermal energy arriving at the earth's surface per day 
per square centimeter averages 430 gram calories at the equator but 
declines to 292 gram calories at the 4Oth parallel and to 87 gram 
calories at the Both parallel . . . (18:16). 

What force sufficiently powerful to counteract that fact of 
astronomy can be suggested, and, more important, supported 
by convincing evidence? 

It was thought at first that universal temperate climates 
might be accounted for by the theory of the cooling of the 
earth. Those who proposed this theory (253, 292) argued that 



ANCIENT CLIMATES 67 

in earlier ages the earth was hotter, the ocean water evapo- 
rated much more rapidly, and it formed thick clouds that 
reflected the sun's radiant energy back into space. The cloud 
blanket shut out the sun's radiation but kept in the heat that 
radiated from the earth itself, and this acted to distribute the 
heat evenly over the globe. The cloud blanket must have 
been thick enough to make the earth a dark, dank, and dismal 
place. Since, as Dr. Colbert shows, fossils are found outside 
the present zones appropriate to them even in recent geolog- 
ical periods, such conditions must have obtained during 
about 90 per cent of the earth's whole history, and most of 
the evolution of living forms must have taken place in them. 

For a number of reasons, including the difficulty of ex- 
plaining how plants can have evolved without sunlight, this 
theory has been abandoned. We have also seen that the idea 
that the earth was even hotter than now has recently been 
undermined. This has destroyed the solidity of the theory's 
basic assumption. 

The fact that the theory never was reasonable is shown 
from Coleman's arguments against it, advanced more than a 
quarter of a century ago. He pointed out that not only are 
ice ages known from the earliest periods (from the Pre- 
Cambrian) but there is evidence that some of these very 
ancient ice ages were even more intensely cold than the 
recent ice age that came to an end 10,000 years ago (87:78). 
No less than six ice ages are known from the Pre-Cambrian 
(430:260). The evidence of one of these Pre-Cambrian or 
Lower Cambrian ice ages is interestingly described by 
Brews ter: 

In China, in the latitude of northern Florida, there is a hundred 
and seventy feet of obvious glacial till, scratched boulders and all, 
and over it lie sea-floor muds containing lower Cambrian trilobites, 
the whole now altered to hard rock (45:204). 

It is obvious that such ice ages (and evidences of more of 
them are frequently coming to light) are in conflict with the 
theory of universal equable climates. Some of them are found 



68 EARTH'S SHIFTING CRUST 

right in the midst of periods thought to have been especially 
warm, such as the Carboniferous. 

Coleman presents other geological evidence against the 
theory. The fact that most of the fossils found are those of 
warm-climate creatures is, he thinks, misleading. Plants and 
animals are more easily fossilized in warm, moist climates 
than they are in cold, arid ones. Fossilization, even under the 
most favorable conditions, is a rare accident. The fauna and 
flora of the temperate and arctic zones of the past were sel- 
dom preserved (87:252). Thus, while the finding of fossils of 
warm-climate organisms all over the earth is an argument 
against the permanence of the present arrangement of the 
climatic zones, it is not an argument for universal mild 
climates. 

Another argument against such climates may be based 
upon the evidences of desert conditions in all geological 
periods. These imply world-wide variations in climate and 
humidity. Both Brooks (52:24-25, 172) and Umbgrove (430: 
265) stress the importance of this evidence. One of the most 
famous formations of Britainthe Old Red Sandstone is, 
apparently, nothing but a fossil desert. Coleman points to 
innumerable varved deposits in many geological periods as 
evidence of seasonal changes (87:253), which, of course, imply 
the existence of climatic zones. 

Ample evidence of the existence of strongly demarcated 
climatic zones through the earth's whole history (at least since 
the beginning of the deposition of the sedimentary rocks) 
comes from other sources. Barghoorn cites the evidence of 
fragments of fossil woods from late Paleozoic deposits in the 
Southern Hemisphere that show pronounced ring growth, 
indicating seasons; he also points out that in the Permo-Car- 
boniferous Period floras existed that were adapted to very 
cold climate (375:242). Colbert himself reports good evidence 
of seasons in the Cretaceous Period, in the form of fossils of 
deciduous trees (375:265). 

Umbgrove cites the geologist Berry, who states that the 
fossilized woods from six geological periods, from the Devo- 



ANCIENT CLIMATES 69 

nian to the Eocene, show well-marked annual rings, indicat- 
ing seasons like those of the present time^ Furthermore, Berry 
goes on to say: 

Detailed comparisons of these Arctic floras with contemporary floras 
from lower latitudes . . . show unmistakable evidence for the exist- 
ence of climatic zones . . . (430:266). 

Brooks concludes, on the basis of Berry's evidence, that cli- 
matic zones existed in the Eocene (52:24). Ralph W. Chancy, 
after a study of the fossil floras of the Tertiary Period (from 
the Eocene to the Pliocene), concluded that climatic zones 
existed (72:475) during that whole period. The distinguished 
meteorologist W. J. Humphreys, whose fundamental work, 
The Physics of the Air, remains a classic, remarked in 1920 
that there was no good evidence of the absence of climatic 
zones from the beginning of the geological record. Finally, 
Dr. C. C. Nikiforoff, an expert on soils (both contemporary 
and fossil soils), has stated that "In all geological times there 
were cold and warm, humid and dry climates, and their ex- 
tremes presumably did not change much throughout geo- 
logical history" (375:191). We will return, below, to the 
significance of fossil soils, and present other evidence showing 
persistence of sharply demarcated climatic zones during the 
earth's history. But where, at this point, does the evidence 
leave us? 

On the one hand, the evidence shows that the plants and 
animals of the past were distributed without regard to the 
present direction of the climatic zones. I have been unable to 
do more than suggest the immensity of the body of evidence 
supporting this conclusion. On the other hand, the attempt 
to deny the existence, in the past, of sharply demarcated cli- 
matic zones like those of the present has failed. It may even 
be said to have failed sensationally. There is no scrap of evi- 
dence for it, except the evidence it is supposed to explain, 
while, on the other hand, it is in contradiction both with 
the fundamentals of astronomy and the preponderance of 
geological evidence. 



70 EARTH'S SHIFTING CRUST 

So we are left with a clear-cut conclusion: Climatic zones 
have always existed as they exist today, but they have fol- 
lowed different paths on the face of the earth. If changes in 
the position of the axis of rotation of the earth, and of the 
earth upon its axis, are equally impossible, and if the drift 
of continents individually is rendered extremely improbable 
for numerous weighty reasons, then we are forced to the con- 
clusion that the surface of the earth must often have been 
shifted over the underlying layers. 



4. The Eddington-Pauly Suggestion 

Another suggestion for displacements of the earth's crust, to 
which I have briefly referred, should now be further dis- 
cussed. Its author, Karl A. Pauly, has contributed new lines 
of evidence in support of such shifts. He has based his dis- 
placement theory on Eddington's suggestion that the earth's 
crust may have been displaced steadily through time by the 
effects of tidal friction. Eddington's idea has serious weak- 
nesses, but the evidence for displacements presented by Pauly 
is most impressive. 

" Pauly suggests that a study of the elevations above sea level 
of the terminal moraines of mountain glaciers in all latitudes 
can establish a correlation of elevation with latitude. It is 
true that many factors influence the distance a mountain 
glacier may extend downward toward sea level, but latitude 
is one of them, and by using a sufficient number of cases it is 
possible to average out the other factors, and arrive at the 
average elevation of mountain glacier moraines above sea 
level for each few degrees of latitude from the equator toward 
the poles. This gives us a curve that makes it possible to com- 
pare the elevations of the terminal moraines of mountain 
glaciers that existed during the Pleistocene Period. Pauly 
finds that these moraines do not agree with the curve, indi- 
cating unmistakably a displacement of the earth's crust (342: 
89). 



ANCIENT CLIMATES 71 

Pauly cites another impressive line of evidence in support 
of his conclusions. He has compared the locations of coal de- 
posits of several geological periods (many of which are now 
in polar regions) with the locations of icecaps for the same 
periods. He lists 34 coal deposits regarded as of Jurassic- 
Liassic age and 17 of Triassic-Thaetic age, and finds that, if 
it is assumed that the centers of the icecaps of that time were 
located at the poles, then these coal deposits would have been 
located within or just outside the tropics, as would be correct 
He says: 

The very definite location of these coal deposits within the Tria- 
Jura tropical and subtropical zones cannot be mere coincidence. The 
distribution indicates the lithosphere has shifted (342:96). 

Of the Permo-Carboniferous coal deposits, which, he 
points out, are very widely distributed over the earth, he 
says that "95 out of 105 listed in The Coal Resources of the 
World lie within or just outside of the tropics as determined 
by the assumption that the North or South Pole lay under the 
center of one of the Permo-Carboniferous ice sheets" (342: 

97)- 



5. The Contribution of George W. Bain 

Not long ago Professor George W. Bain, of Amherst, in an 
article in the Yale Scientific Magazine (18), went considerably 
beyond the categories of evidence that we have so far con- 
sidered. He discussed the specific chemical processes con- 
trolled by sunlight and varying according to latitude, and the 
remanent chemicals typical of soils developed in the different 
climatic zones. He extended this sort of analysis also to 
marine sediments. 

Bain's approach to the problem of evidence of climatic 
change has many advantages. It avoids, for one thing, the ob- 
jection that has been raised against some of the plant evi- 
dence: that plants of the past may have been adjusted to 



72 EARTH'S SHIFTING CRUST 

climates different from those in which their modern descend- 
ants live. I believe his method establishes beyond question 
the existence of climatic zones all through the geologic past. 

Dr. Bain begins with a precise definition of each climatic 
zone in terms of the quantities of the sun's heat reaching the 
earth's surface. He points out that, as is known, the seasonal 
variation of this heat increases with distance from the equator 
(18:16). He then describes the global wind pattern resulting 
from this distribution of the sun's energy, defining clearly 
the conditions of the horse latitudes, in which most of the 
earth's deserts are found, and the meteorology of the polar 
fronts. He shows that there are distinct and different com- 
plete chemical cycles in each of these areas, and correspond- 
ing cycles in the sea. Many of the chemical compounds pro- 
duced in each of these areas are included, naturally, in the 
rocks formed from the sediments, and they remain as perma- 
nent climatic records. 

It is impossible, because of limitations of space, to do jus- 
tice to Dr. Bain's comprehensive approach to this question. 
There appears to be no room for doubt, however, that great 
differences exist between the mineral components of the 
different climatic zones, as determined by the amount of the 
sun's radiant heat. With regard to the polar soils, in addition, 
it is noteworthy that they are developed in circles on the 
earth's surface, rather than in bands. Temperate and tropical 
soils are, of course, found in bands, since the zones are bands 
that encircle the earth. 

It will be clear to the reader that Dr. Bain has established 
a sound method for the study of the climates of the past. He 
has applied his method to the study of the climates of two 
periods, the Jurassic-Cretaceous and the Carboniferous-Per- 
mian, with very significant results. He has concluded, first, 
that climatic zones, representing the different distributions of 
solar heat, existed in those periods just as at present. This is 
proved by the specific remanent chemicals included in these 
rocks, which differ exactly as do the sediments of the different 



ANCIENT CLIMATES 73 

zones at the present time. This is, of course, fatal for the 
theory of universal equable climates. 

His second conclusion, of even greater importance, is that 
the directions of the climatic zones have changed enormously 
in the course of time. He finds the equator running through 
the New Siberian Islands (in the Arctic Ocean) in the Permo- 
Carboniferous Period, and North and South America lying 
tandem along it (18:17). The evidence he uses seems to 
establish his essential point (and ours) that the climatic zones 
themselves have shifted their positions on the face of the 
earth. 

Dr. Bain has drawn some interesting further conclusions. 
He states that the earth's crust must have been displaced over 
the interior layers, and that "fixity of the axis of the earth 
relative to the elastic outer shell just is not valid. . . ." (18: 
46). He points to the fossil evidence of the cold zones (dis- 
tributed in circular areas) and says, ". . . The recurrent 
change in position of these rings through geologic time can 
be accounted for now only on the basis of change in the posi- 
tion of the elastic shell of the earth relatively to its axis of 
rotation" (18:46). 



6. The Contribution of T. Y. H. Ma 

Dr. Bain pointed out, in the paper above mentioned, that 
among other indications of latitude, sea crustaceans and 
corals may indicate latitude either by the presence or absence 
of evidence of seasonal variations in growth. It happens that 
corals have been very thoroughly investigated from precisely 
this point of view. 

By a remarkable parallelism of development, another the- 
ory of displacement of the earth's crust took shape on the 
opposite side of the earth at about the same time that Mr. 
Campbell and I started on our project. Professor Ting Ying 
H. Ma, an oceanographer, then at the University of Fukien, 
China, came to the conclusion, after many years of study of 



74 EARTH'S SHIFTING CRUST 

fossil corals, that many total displacements of the earth's 
whole outer mantle must have taken place. I did not become 
aware of Professor Ma's work until I was introduced to it by 
Dr. David Ericson, of the Lament Geological Observatory, in 
1954. Dr. Ericson has, in fact, taken a leading role in intro- 
ducing Professor Ma's work to American scientists. 

For about twenty years previous to the time I mention, 
Professor Ma had intensively pursued the study of living 
and fossil reef corals. He very early noticed that characteristic 
of reef corals referred to by Dr. Bain, but hitherto ignored 
by writers on corals. He saw that, at distances from the 
equator, there were seasonal differences in the rates of coral 
growth, and that the evidences of these were preserved in the 
coral skeleton. Specifically, he observed that in winter the 
coral cells are smaller and denser; in summer they are larger 
and more porous. Together, these two rings make up the 
growth for one year. 

Studying living coral reefs in various parts of the Pacific, 
comparing, measuring, and tabulating coral specimens of 
innumerable species, making photographic studies of the 
coral skeletons, Professor Ma established that the rates of 
total annual coral growth for identical or similar species 
within the range of the coralline seas increased with prox- 
imity to the equator, and that seasonal variation in growth 
rates increased with distance from the equator. 

Other writers on corals have pointed out that there are 
numerous individual exceptions and irregularities in coral 
growth rates, deriving from the fact that the coral polyps feed 
upon floating food, which may vary in quantity from place 
to place, from day to day, and even from hour to hour (125: 
20-21; 298:52-53). Professor Ma, however, has guarded him- 
self against error by a quantitative and statistical approach. 
In several published volumes of coral studies (285-290) he 
has compiled tables running into hundreds of pages, and his 
studies have involved thousands of measurements. 

When this indefatigable oceanographer had worked out 
these relations of growth with latitude, he possessed an effeo 



ANCIENT CLIMATES 75 

tive tool with which to investigate the climates of the past. It 
was possible now to arrive at a very good idea of the condi- 
tions under which fossil corals grew. Professor Ma studied 
hundreds of specimens of fossil corals from many of the geo- 
logical periods. He devoted entire separate volumes to each 
of the Ordovician, Silurian, Devonian, Cretaceous, and Ter- 
tiary Periods (285-289). 

As Ma assembled the coral data for past periods, it became 
plain to him that the total width of the coralline seas had 
never varied noticeably from the beginning of the geological 
record. Not only was the existence of seasons, of climatic 
zones, in the oldest geological periods clearly indicated; it 
was also indicated that the average temperatures of the re- 
spective zones were about the same as at present. 

The second result of Ma's studies was to establish that the 
positions of the ancient coralline seas and, therefore, of the 
ancient equators were not the same as at present. They 
changed from one geological period to another. Ma first came 
to the conclusion that this could be explained only by the 
theory of drifting continents. Down to about 1949 he sought 
to fit the evidence into that theory. By 1949, however, the 
continuing accumulation of the evidence led him to adopt 
the theory of total displacements of all the outer shells of the 
earth over the liquid core. By some instinct of conservatism, 
however, he did not abandon the theory of floating conti- 
nents, but combined it with the new theory. 

Ma's coralline seas ran in all directions; one of his equators 
actually bisected the Arctic Ocean. But he had great diffi- 
culty in matching up his equators on different continents. 
If, for example, he traced an equator across North America, 
he could not match it with an equator for the same period 
on the other side of the earth, to make a complete circle of 
the earth. He therefore supposed that the continents them- 
selves had been shifting independently, and this had had the 
effect of throwing the ancient equators out of line. He there- 
fore allowed, for each period, enough continental drift to 
bring the equators into line, and it seemed, when he did 



76 EARTH'S SHIFTING CRUST 

this, that in successive geological periods he did have increas- 
ing distances between the continents, as if the drift had been 
continuous. 

Subsequently, Professor Ma developed his theory into a 
complete system, which is most interesting, and yet to which, 
I think, serious objections may be raised. 

Corals are, according to Ma, excellent indicators of the 
climate for the time in which they grew, but, by the nature 
of the case, since corals grow only in shallow water, and grow 
upwards only as far as the surface, the period of time repre- 
sented by a single fossil coral reef is of the order of a few 
thousand years only, as compared with the millions of years 
embraced by a geological period. 

How short the continuous growth of a coral reef may be 
is indicated by numerous studies of the coral reefs of the 
Pacific. A. G. Mayor, for example, says: 

. . . The modern reefs now constituting the atolls and barriers of 
the Pacific could readily have grown upward to sea-level from the 
floors of submerged platforms since the close of the last glacial epoch 



At Pago Pago Harbor borings were made down to the 
basalt underlying the reef, and after estimates of the growth 
rate were arrived at, the age of the reef (Utelei) was esti- 
mated at 5,000 years. When these spans are compared with 
those of entire geological periods of the order of 20,000,000 
or 30,000,000 years, it is clear how fragile must be any con- 
clusions based on the assumption that a given coral reef in 
Europe was contemporary with another one in North Amer- 
ica. It is quite impossible in the present state of our knowl- 
edge to decide that they were in fact contemporary. 

This means that Ma's corals for a period like the Devonian 
may be indications of different equators that existed at differ- 
ent times during that period of 40,000,000 years. Therefore 
it is obvious that thousands of coral specimens would be re- 
quired to give any certainty as to the actual climatic history 
of an entire geological period. 



ANCIENT CLIMATES 77 

Very possibly Ma could have avoided combining the two 
different theories the slipping of the shell of the earth and 
the drifting of continents if he had supposed a sufficiently 
frequent slipping of the crust. The frequency of the displace- 
ments suggested by the theory presented in this book, which 
would involve many different equators in a single geological 
period, would remove his difficulties. As it is, he has to face 
all the geophysical and geological objections to the drifting 
continent theory, as well as difficulties with his displacement 
theory. 



7. On the Rate of Climatic Change 

Studies appear from time to time in which attempts are made 
to trace climatic changes in specified areas over periods of 
millions of years. In one of these, for example (72), the con- 
clusion is reached that there was a gradual cooling of the 
climate during a great many million years of the Tertiary 
Period. It is true that no cause of such a progressive cooling 
can be pointed to; neither is there any explanation as to why 
the climatic change had to be so gradual. It is simply assumed 
that the climatic change had to be gradual, and that the cause 
of the change had to be such as to explain imperceptible 
climatic changes over millions of years of time. 

It is important to define as clearly as possible the nature 
of the evidence on which these conclusions are based. In the 
example I am considering, the following facts have decisive 
importance: 

a. The period of time involved in an alleged cooling of 
the climate is of the order of 30,000,000 years. 

b. Wherever reference is made to the specific strata of rock 
selected for analysis of the climatic evidence (consisting 
of included fossils), it is clear that the time required for 
the deposition of a particular layer was of the order of 
10,000 years. 



78 EARTH'S SHIFTING CRUST 

c. It follows that during 30,000,000 years it would be pos- 
sible to have about 3,000 different layers of sedimentary 
rock. 

d. A vast majority of these layers cannot be sampled, either 
because they no longer exist, or because they do not 
contain fossils, or simply because of the amount of work 
involved. 

e. As a result, only the most unsatisfactory kind of spot 
checking is possible. Perhaps a dozen strata out of 3,000 
may be studied, and from these it must be obvious that 
no dependable climatic record can be established. 

f. Even with the unsatisfactory spot checking so far at- 
tempted, reversals of climatic trends have been ob- 
served (72). 

g. Climatic conditions indicated by a layer of sediments 
deposited during a brief period of time in one location 
cannot be assumed to indicate the direction of climatic 
change over a great region, or over the whole earth. It 
seems quite as reasonable to suppose that climatic 
change in other regions at the same time was in a differ- 
ent direction. Furthermore, it cannot be assumed that 
two sedimentary deposits in different areas are of the 
same age because they both indicate climatic change in 
the same direction. 

It must be concluded that all claims for gradual climatic 
changes in the same direction over long periods of time and 
over great areas are unsupported by convincing evidence. 
The existence of such long-term trends can be supported 
by no reasonable hypothesis. We are left with the conclusion 
that climatic change has probably taken place within rela- 
tively short periods of time, and possibly in opposite direc- 
tions for different areas at the same time, as, indeed, would 
be a natural consequence of displacements of the earth's 
crust. 



IV : THE MOUNTAINS 



PART I. The Folding and Fracturing of the Crust 

By far the most magnificent features of the earth's crust are 
the lofty mountain ranges that are found on all the conti- 
nents, exciting the wonder of man, and those other, equally 
tremendous mountain ranges that lie drowned in the silent 
depths of the sea. These mountain ranges carry in their in- 
tricate formations much of the history of the earth's crust. If 
we could know the forces that produced them, we could grasp 
the basic dynamic principles of the earth's development. Un- 
fortunately, though the mountains have long been the sub- 
ject of intensive scientific investigation, they have preserved 
their secrets well. The most important of these secrets is the 
secret of their birth. What forces within the earth were re- 
sponsible for their formation? As of now, we do not know. 

Nothing could better betray the extent of our ignorance 
of the dynamic processes that have shaped the face of the 
earth than this confession of ignorance. Yet, it is agreed by 
geologists that no theory has so far satisfactorily explained 
mountain building. Daly, for example, has referred to the 
process of the folding of the rock strata, a phase of mountain 
building, as "an utterly mysterious process" (7od:4i). Guten- 
berg has concluded that none of the present theories will do. 
He remarks that "all the forces discussed so far seem to be 
insufficient to produce the formation of mountains" (194: 
171), and this includes, of course, the long-exploded (but still 
widely current) theory that ascribes mountains to the cooling 
and shrinking of the earth. As to this, Gutenberg remarks, 
". . . other scientists have pointed out that the cooling of 
the earth is not sufficient to produce the major part of the 
crumpling, especially since investigations of the radioactive 
heat which is produced inside the earth have indicated that 



8o EARTH'S SHIFTING CRUST 

the cooling of the earth is less than it had been originally be- 
lieved. . . ." (194:192). Bullard, reviewing the third edition 
of Harold Jeffreys's basic work, The Earth, notes the absence 
of progress toward solving the problem of mountain build- 
ing, since the second edition twenty-five years ago (59). 
Pirsson and Schuchert, the authors of a general text on geol- 
ogy, conclude a section on the cause of mountain building 
with the statement: "It must be admitted, therefore, that the 
cause of compressive deformation in the earth's crust is one 
of the great mysteries of science, and can be discussed only in 
a speculative way" (345:404). 

What is the nature of this problem that has so far baffled 
science? 



/. The Problem of Crustal Folding 

It is important to take into account the fact that there are sev- 
eral different kinds of mountains, and that their origins may 
be ascribed to somewhat different circumstances, even though 
(as we shall see) they may be related to one underlying cause. 
Some mountains are caused by volcanic eruptions. These con- 
sist of piles of volcanic matter. Some of the greatest moun- 
tains on the earth's surface are volcanic mountains. Many 
of them are found on ocean bottoms, and when they rise to 
the surface they form the island chains (such as the Hawai- 
ians) that are especially numerous in the Pacific. Sometimes 
volcanic islands or mountains can be formed quickly, as was 
the case recently in Mexico, where a large mountain, 
Paricutfn, was developed in a few years to a height of several 
thousand feet from a lava flow that started in a cornfield on 
the level ground. Some mountains result from a vast flow of 
molten rock that gathers under the crust at one spot and 
domes it up. The causes of these events are unknown. 

Many mountains, and even whole ranges of mountains, are 
brought into existence in part by the cracking of the earth's 
crust, accompanied by the tilting of the separated blocks. The 



THE MOUNTAINS 8l 

Sierra Nevada Mountains of California appear to have been 
formed in this way. According to Daly, they represent the 
tilting of a single block of the earth's crust some 600 miles 
long (98:90). Some folding of the crust, however, had previ- 
ously taken place. Many great chasms, extended cliff forma- 
tions, and rift valleys appear to have been formed by the 
cracking and drawing apart of the crust, and by the elevation 
or subsidence of the different sides. The great African Rift 
Valley is perhaps the best-known example of this sort of 
formation; the rift of which it is a part, as we shall see below, 
has recently been connected with a world-wide system of 
great submarine rifts. The cause of all this cracking and 
tilting is still one of the mysteries of science. 

The greatest mountain systems on the earth's surface have 
been formed as the result of the lateral compression and fold- 
ing of the crust. Since folding is the cause of most mountain 
building it must hold our particular attention. As already 
suggested, science is particularly at a loss to explain the fold- 
ing. A number of suggestions have been advanced, but they 
are all deficient for various reasons. 

A part of the public is under the impression that moun- 
tains have been formed by the action of running water, wear- 
ing away the stone, eroding the tablelands, and depositing 
layers of sediment in the valleys and in the sea. Although it 
cannot be denied that erosion has been a powerful factor in 
shaping many mountains, and may have been the main factor 
in shaping some of them (for example, Mt. Monadnock, in 
New Hampshire, which I can see from my window as I write 
these words), it cannot have been the principal cause of the 
formation of our great folded mountain ranges. 

Geologists who have argued in favor of this theory have 
pointed out that the deposition of sediment in narrow crustal 
depressions may have been a cause of the folding of the crust. 
The folding could have resulted in part from the sinking of the 
valley bottoms under the weight of the sediments. The proc- 
ess will be found described in detail in almost any textbook 
of geology. There are serious objections to it, and no geol- 



82 EARTH'S SHIFTING CRUST 

ogist today considers it a satisfactory explanation. One ob- 
jection is that this process of folding is essentially locaL It 
cannot explain the greatest mountain systems, spme of which 
virtually span the globe. It cannot explain, for example, the 
almost continuous line of mountain ranges that includes the 
Rockies, the Andes, and the Antarctic Mountains, and which 
extends for a total distance of almost half the circumference 
of the earth. Neither can this theory explain the numerous 
submarine mountain ranges that have, in recent years, been 
discovered on the bottoms of the Atlantic, Pacific, and Arctic 
Oceans. Moreover, it has been pointed out that in many cases 
folding of the crust has taken place without any deposition of 
sediment, and therefore must have been due to other causes. 
The geologist Henry Fielding Reid remarked: 

. . . There are many deeps in the ocean, such as the Virgin Islands 
Deep, the Tonga Deep, and others, which appear to have sunk with- 
out any material deposit of sediments. . . . (354). 

For these various reasons, then, geologists have come to the 
conclusion that erosion is only a secondary cause of mountain 
building (345:382-84). We shall consider this again. 

Another common impression, as already mentioned, is that 
mountain formation has been due to the cooling and shrink- 
ing of the earth. It was reasonable, perhaps, as long as the 
theory of the cooling of the earth was unquestioned, to try 
to explain the origin of folded mountains in this way, for, of 
course, if the earth shrank in size, even only slightly, as a re- 
sult of cooling, some wrinkling of the crust must be the 
result. The fact that the pattern of wrinkles that would be 
produced in this way (and which could be deduced fairly 
clearly) bore no resemblance whatever to the patterns of the 
existing mountain ranges, did not greatly diminish the cur- 
rency of this theory, though it did bring about a devastating 
attack upon it by one competent geologist whose views we 
shall discuss below. 

We have seen that there is now an impressive body of evi- 
dence and opinion against the theory of a molten origin for 



THE MOUNTAINS 8j 

the earth. The doubts that have gathered about this assump- 
tion are sufficiently serious to prevent us from basing any 
theory of mountain building upon it (for no theory can 
have greater probability than its own basic assumptions). But 
even if this were not the case, even if the molten origin of the 
earth were a demonstrated fact, still, it was pointed out 
twenty-five years ago, by Clarence Button, that the shrinking 
of the globe would not explain the folded mountains. Button 
had two objections. First, he said that the calculated amount 
of the shrinkage that could have occurred since the crust was 
formed, by the reduction of temperatures, would not account 
for the volume of the mountains known to have existed dur- 
ing geological history. Secondly, he pointed out that the 
kinds of pressures that would exist in the crust as a result of 
the shrinking of the earth could not produce mountain 
ranges of the existing patterns. On this point, he said: 

... As regards the second objection, which, if possible, is more 
cogent still, it may be remarked that the most striking features in the 
facts to be explained are the long narrow tracts occupied by the belts 
of plicated strata, and the approximate parallelism of their folds. 
These call for the action of some great horizontal force thrusting in 
one direction. Take, for example, the Appalachian system, stretching 
from Maine to Georgia. Here is a great belt of parallel synclinals and 
anticlinals with a persistent trend, and no rational inquirer can doubt 
that they have been puckered up by some vast force acting hori- 
zontally in a northwest and southeast direction. Doubtless it is the 
most wonderful example of systematic plication in the world. But 
there are many others that indicate the operation of the same forces 
with the same broad characteristics. The particular characteristic with 
which we are concerned is that in each of these folded belts the hori- 
zontal force has acted wholly or almost wholly in one direction. But 
the forces that would arise from a collapsing crust would act in every 
direction equally. There would be no determinate direction. In short, 
the process would not form long narrow belts of parallel folds. As I 
have not time to discuss the hypothesis further, I dismiss it with the 
remark that it is quantitatively insufficient and qualitatively inap- 
plicable. It is an explanation that explains nothing that we want to 
explain. . . . (122:201-02). 

It is indeed astonishing to note that though a quarter of a 
century has passed since this statement was made, and though 



84 EARTH'S SHIFTING CRUST 

leading geophysicists today sustain Button's views (194:192), 
the impression is still widespread, and not merely among lay- 
men, that mountains are, more or less, understandable as 
the consequence of the cooling of the earth. The cause of this 
inertia is, very likely, the absence of any alternative, accept- 
able theory of mountain building. 

In recent years many geologists have agreed with Button 
that the mountains were folded by some immense force oper- 
ating horizontally on the earth's crust. Furthermore, they 
have come to recognize that the force or forces involved in 
mountain folding acted on the earth's crust as a whole and 
at the same time. Thus, one of our leading geophysicists, Br. 
Walter Bucher, of Columbia, remarked: 

Taken in their entirety, the orogenic [mountainous] belts are the 
result of world-wide stresses that have acted on the crust as a whole. 

Certainly the pattern of these belts is not what one would expect 
from wholly independent, purely local changes in the crust (58:144). 

The same thing was pointed out by Br. Umbgrove: 

. . . But the growing amount of stratigraphic studies make it in- 
creasingly evident that the terrestrial crust was subjected to a period- 
ically alternating increase and decrease of compression. ... I feel 
there is overwhelming evidence that the movements are the expression 
of a common, world-wide, active, and deep-seated cause. . . . (430:31). 

Br. Umbgrove was impressed by another characteristic of 
this world-wide force. It did not act continuously. It was not 
always acting to expand or squeeze sectors of the crust to fold 
them into mountains. It acted only at certain times, and 
then, for other periods, it was inactive. There was a sort of 
periodicity to its operation. This periodicity extended also 
to other aspects of the earth's geological history: 

The geologist comes across periodicity in many of the pages which 
he is arduously decipheringin the sequence of the strata, for in- 
stance, and their contents of former organisms. . . . He observes it 
elsewhere, in the deep-seated forces that bring subsidence first in one 
area and then in another ... in the intrusion of liquid melts or 
"magma" rising from some deeper part of the earth's interior; in the 



THE MOUNTAINS 87 

ing. Joly attempted to prove that the accumulation of radio- 
active heat in the earth resulted in mountain building at 
intervals of 30,000,000 years (244; 235:153). Gutenberg, how- 
ever, says that details of Joly's theory have been disproved 
(194:158) and, moreover, that the theory includes no mecha- 
nism to account for the 3o,ooo,ooo-year intervals (194:188). 
It is impossible to see that the resulting upheaval of the 
surface could produce mountain ranges of the patterns that 
exist. Joly's theory does postulate a growing earth, but 
whether the crust bursts occasionally or is continually col- 
lapsing because of shrinking, it all amounts to the same 
thing: neither theory meets the requirements. Attempts have 
also been made to explain periodicity as the result of long- 
range astronomical cycles, but they have been unsuccessful 
(430:281-82). It is obviously difficult to explain mountain 
building by astronomical cycles. 

For some years, geologists have been looking for a moun- 
tain-folding force below the earth's crust. They have been 
investigating the possibility of the existence of currents in 
the semiliquid layers under the crust, and speculating on the 
possible effects of such currents, if they exist, on the crust 
itself. It has been suggested that such currents, rising under 
the crust, or sinking, might fold the crust. A sinking current, 
for example, would have the effect of drawing the crust to- 
gether over it, and pulling it down, forming wrinkles, in 
long narrow patterns, like the mountain ranges. Calculations 
have been made of the forces that could be brought to bear 
upon the crust in this way. Vening Meinesz prefers this way 
of accounting for mountain building: 

If we examine the pattern of great geosynclines over the earth's 
surface, we cannot doubt that their cause must have a world-wide 
character. The geology in these belts points to horizontal compression 
in the crust, at least during the later stages of their development. The 
two main hypotheses suggested to explain these great phenomena are 
(i) the thermal-contraction hypothesis, and (2) the hypothesis of sub- 
crustal current systems of such large horizontal dimensions that, ver- 
tically, they must involve at least a great part of the thickness of the 
mantle and probably the whole mantle (349:319). 



88 EARTH'S SHIFTING CRUST 

Vening Meinesz summarizes the arguments against the 
thermal-contraction hypothesis (the cooling of the earth), 
and argues for the second theory. It is interesting, in passing, 
to note that one of his arguments against the contraction 
theory is that "In large parts of the earth's surface . . . ten- 
sion seems to exist in the crust at the same time that folding 
takes place elsewhere, and this fact is difficult to reconcile 
with thermal contraction (giving compression) throughout 
the crust. . . ." (349:320). He is here saying that the earth's 
crust was being stretched in some places and compressed in 
others, at the same time, which is inconsistent with the cool- 
ing and contracting theory. It is, however, quite consistent 
with the crust displacement hypothesis. 

Now, as to the subcrustal current hypothesis, we may note 
that Meinesz is assuming currents travelling for great dis- 
tances horizontally, and moving in great depths of hundreds 
of miles below the crust. Naturally, the movement of such 
masses of rock could potentially create pressures to stagger 
the imagination. Gutenberg discusses the work of many men 
who are studying subcrustal currents (194:186, 191). The 
chief weakness of the theory is the absence of any real evi- 
dence for the existence of such currents. It is suggested, for 
example, that thermal convection might account for them, 
or chemical changes of state in depth might account for 
them, or mechanical factors might be at work, but, mean- 
while, there is no real evidence that such currents really 
exist. Some geologists have claimed to have found evidence 
of cyclonelike patterns in rock structures (194:188), but these 
appear to have been of small magnitude; they therefore may 
have been formed in small pockets of molten rock. They do 
not provide reliable evidence for the existence of gigantic 
crust-warping currents, such as would be required for moun- 
tain building. 

The problem that we are involved with here is that of the 
origin of the geosyncline. Geologists refer to a downward fold 
in the crust of major proportions as a geosyncline. An up- 
ward fold (or arch) is a geoanticline. They are sometimes 



THE MOUNTAINS 91 

ments and possibly through a number of successive displace- 
ments of the crust, to the formation of folded mountain 
ranges. 

The systematic presentation of this theory requires us to 
consider the two different phases of displacement equator- 
ward and poleward separately, for they have very different 
results. We will begin with the consideration of the effects 
of a displacement of a crustal sector toward the equator. 

In a shift in that direction, a crustal sector is submitted 
to tension (or stretching), and this tension is relieved by the 
fracturing that takes place when the bursting stress exerted 
on the crust has come to exceed the strength of the crust. (For 
Mr. Campbell's calculations of the quantity of the bursting 
stress, as compared with estimates of crustal strength, see 
Chapter XI.) Until fractures appear and multiply, the crust 
caijnot move over the bulge. After the fracturing permits 
the movement to begin, the crustal blocks tend to draw 
slightly apart. The spaces between them are immediately 
filled by molten material from below. 

Let us form a clear picture of this crustal stretching, from 
the quantitative standpoint. It is important to estimate the 
stretch per mile, if we are to visualize the results. Taking the 
globe as a whole, the difference between the polar and equa- 
torial diameters is about 26 miles. The circumferences, 
therefore, differ by about 78 miles. If the crust were dis- 
placed so far that a point at a pole was displaced to the 
equator, the polar circumference would have to stretch 78 
miles to fit over the equator. This would amount to about 
17 feet in the mile. Since the magnitude of displacements, 
however (according to evidence to be presented later), seems 
to have been of the order of no more than about 30 degrees, 
or one third of the distance from pole to equator, the average 
stretch per mile may have amounted to five or six feet, or 
one foot in a thousand. 

It would be a mistake to visualize this stretching of the 
crust in the equatorward-moving areas as evenly distributed 
around the whole circumference of the globe. Obviously, the 



g2 EARTH'S SHIFTING CRUST 

real events would not correspond to this. The crust would 
be under bursting stress, and this would be relieved spas- 
modically, during the movement of the crust, by fractures at 
the weakest points. A fracture through the crust at one point 
would relieve the stress for perhaps hundreds of miles. Since 
the elasticity of the crust is slight, the stretching or extension 
of the crust would consist of the drawing apart, to varying 
distances, of the fractured blocks. Generally speaking, the 
fewer the fractures, the farther their sides would draw apart. 
It would be possible that the total amount of the stretching 
of the earth's circumference would be concentrated in rela- 
tively few critical areas. 

It must also be kept in mind that some parts of this area 
being displaced toward the equator will be displaced farther 
than others. The greatest displacement will occur along the 
line, or meridian, drawn from the pole through the center of 
mass of the icecap and so around the earth; or, if any unex- 
pected factor should deflect the direction of the movement, 
the greatest displacement will occur along whatever meridian 
represents the direction of the movement. As I have pointed 
out, at two pivot points on the equator 90 degrees away from 
this meridian there will be little or no movement, and the 
points in between will move proportionately to their dis- 
tances from the meridian. The tension, or stretching, will be 
proportional to the amount of displacement. It therefore will 
be greatest along the central meridian of movement, and it 
is here that Mr. Campbell expects the first major fractures 
of the crust to develop. 

It is important to visualize the nature of the crust on which 
this tension is exerted. The crust is comparatively rigid, hav- 
ing little elasticity, but it is not strong. It varies in thickness 
and strength from place to place. As we shall see, it is even 
now penetrated by great systems of deep fractures of unex- 
plained origin. These inequalities of strength will be very 
important in determining the reactions of the crust from 
place to place to the tension exerted upon it; they will de- 



THE MOUNTAINS 93 

termine the precise locations, and to some extent the pat- 
terns, of the fractures that will result. 

Without attempting to anticipate a more detailed discus- 
sion, to be introduced later, of the forces involved in this 
fracturing of the crust, I would like to remark that the forces 
required for the fracturing are by no means so great as might 
be at first supposed. It is a question of relatively slight forces 
exerted over considerable periods of time. 

If we disregard the factors that may locally influence the 
locations and sizes of fractures, a general pattern may be indi- 
cated to which they will tend to conform. Mr. Campbell has 
worked out this pattern schematically, and has indicated it in 
Figures II, III, and IV. The reader will note that the fractures 
take two directions. There are the north-south, or meridional, 
fractures, which Mr. Campbell refers to as the major frac- 
tures, and then there are minor fractures at right angles to 
them. 

Mr. Campbell anticipates that numerous major fractures 
will occur parallel to each other as the crust moves. The for- 
mation of very numerous minor faults at right angles to the 
major faults will form a gridiron pattern of fractures. Mr. 
Campbell has suggested a method for visualizing the process. 
If the reader will cup his hands and place them together, 
with fingertips touching and the fingers of each hand close 
together (as if they lay on the surface of a sphere), and then 
imagine the sphere growing, and causing the fingertips of 
both hands to spread apart, and at the same time the fingers 
of each hand to spread apart, he may visualize the process. 
The gap between his hands will now represent a major frac- 
ture, and the gaps between the fingers of each hand will 
represent the minor fractures at right angles to it. The reader 
will see, a little later on, how closely this projection of frac- 
ture effects corresponds to the real phenomena in the earth's 
crust. 

Another important aspect of these fractures is shown in 
Figure III. Mr. Campbell has indicated that, owing to the 
changing arc of the surface as the crustal sector moves 



94 



EARTH'S SHIFTING CRUST 




Fig. II. Mountain Building: Patterns of Fracture and Folding 
The lithosphere, or crust, is represented in a future movement resulting 
from the effect of the present icecap in Antarctica. Since the latter' s 
center of mass is on (or near) the meridian of 96 E. Long., the crust is 
represented as moving in that direction from the pole. The sector of 
expansion is moving equatorward and therefore being extended. The 
sector of contraction is moving toward the North Pole from the equator 
and therefore being compressed. 

In the sector of expansion, parallel major faults can be observed, with 
minor faults at right angles. The wavy lines suggest the effects of local 
differences in crustal strength. The pattern of the fractures is indicated, 
but not their number; a very large number of meridional fractures 
might be formed, while the minor fractures would be even more 
numerous. 

In the sector of contraction, crustal folding is shown only schemat- 
ically. It is represented as if all the folding is taking place along one 
meridian, although in reality there would probably be many parallel 
zones of mountain folding at considerable distances from each other. 
Campbell indicates that this movement will be accompanied by frac- 
turing of the crust, with faults running at right angles to the main axes 
of the folds. The third axis, which runs through the equator, is consid- 
ered to be the axis on which the crust turns. The points directly at the 
two ends of this axis do not move. 



THE MOUNTAINS 



95 




POSITION OF 
UTH05PHERE 
IF NOT PUUEt> 
DOWN BY GRAVITY 



NORTH POLE 



Fig. III. Vertical View of the Earth with Cross Section at 96 E. Long. 
This figure illustrates a number of simultaneous effects of displacement. 
The upper right-hand quadrant shows a sector of the crust displaced 
toward the equator. Here the lessening arc of the surface will cause 
faults to open from the bottom. The lower right-hand quadrant shows a 
sector of the crust displaced toward a pole. Here the increasing arc of 
the surface results in faults opening from the top. The lower left-hand 
quadrant, which is a vertical view of a sector moving equator-ward, shows 
major meridional faults, which have opened from the bottom. The 
upper left-hand quadrant, which is a vertical view of a sector displaced 
poleward, shows meridional faults opening from the top. 

The reader should visualize the left-hand quadrants as if looking 
straight down on the earth at the point where the central meridian of 
displacement (96 . Long, in this case) crosses the equator. 

NOTE: In this and other drawings the South Pole has been shown at the 
top, reversing the usual position. This has been done for reasons of con- 
venience and because our theory has been developed with the Antarctic 
icecap as the center of attention. In actuality, there is no such thing as 
"up" or "down" in space. The North Pole is usually shown at the top, 
but this is merely a convention of cartographers. 



EARTH'S SHIFTING CRUST 



CQUVTORtAt - 




Fig. IV. Patterns of Fracture 

This figure indicates schematically the mechanics of faulting and folding 
in a displacement of the crust. It is suggested, for purposes of illustra- 
tion only, that all effects are concentrated on the meridian of maximum 
crust displacement. Therefore, only one major meridional fault is shown 
in the upper hemisphere, which is moving toward the equator. Dotted 
lines indicate other faults opening from the bottom of the lithosphere, 
or crust, as the arc of the surface diminishes. 

Across the equator, where the surface is moving toward the pole, and 
compression is resulting, the continuation of the major expansion fault 
is shown as a pressure ridge, which may later become the main axis of 
a mountain range. Again, for purposes of illustration only, it is assumed 
that all folding will take place along the meridian of maximum dis- 
placement. If the major fault is filled with molten magma, and the 
magma solidifies, then this intruded matter, which has expanded the 
crust, must add to the folding in the lower hemisphere, which is moving 
toward a pole. 

In the lower hemisphere the unbroken lines indicate the fractures 
opening from the top, as the arc of the surface increases. 

equatorward, the fractures will tend to open from the bot- 
tom. This would, of course, favor the intrusion into them of 
magma from below, and, accordingly, Mr. Campbell shows 
them filled up (in black). At the same time, as the reader may 



THEMOUNTAINS 97 

see, fractures in areas moving poleward would tend to open 
from the top. These might be less likely to reach sources of 
molten rock; accordingly, they are not shown filled up. 
Whether these fractures would or would not fill up (and 
perhaps the probabilities are that they would), the configura- 
tion of the resulting solidified veins in the rocks would be 
very different from that in fractures that had opened from 
the bottom. Campbell has suggested that this way of explain- 
ing existing fracture patterns in the crust could be an aid 
in prospecting for ores, most of which occur in such veins. 
It would be a question of ascertaining, for the general region, 
whether the veins being investigated were part of either a 
poleward type or equatorward type of pattern, and from this 
it might be possible to deduce whether the vein was to peter 
out or not. Campbell believes that the hypothesis provides 
numerous possibilities for the exploration of the crust, some 
of which may prove eventually to be of commercial value. 

The time element is essential to visualizing the general 
process of a displacement. Some concept of the probable 
speed of the displacement is required. A basis for such an 
estimate is provided by evidence that will be fully considered 
later, but I may here anticipate by saying that displacements 
may have required periods of from 10,000 to 20,000 years. 
This means that this amount of time would be available for 
the creation of the system of fractures we are considering. It 
means, for example, that a single major fracture, which might 
involve, let us say, the pulling apart of the crust to a distance 
of several miles and the filling up of the crack with molten 
material from below, might be formed over a period of 
several thousand years, during which time there might be 
spasmodically renewed earthquake fracturing and volcanic 
effects, interrupted by periods of quiet. It is obvious that the 
amount of time available for the work of extension and frac- 
turing of the crust is sufficient to permit the process to com- 
plete itself without undue or incredible violence. 

We must now consider a question that relates to mountain 
building, and at the same time involves another of the major 



98 EARTH'S SHIFTING CRUST 

unsolved problems of geology. It is connected with our phase 
of equatorward crust displacement. It has to do with the 
filling of the fractures by molten magma from below. Camp- 
bell considers that this filling of the fractures is the first step 
in mountain building, or at least in the formation of a 
geosyncline. Obviously, it is possible to start the process at 
other points; this is therefore only a matter of convenience, 
and for the purpose of drawing a clear picture of the process 
for the reader. But Mr. Campbell points out that the process 
of the filling of the cracks, and the later solidification of the 
intruded material, adds extension to the crust; there is now 
more surface. When, in future shifts of the crust, this area 
passes over the equator toward a pole, or moves poleward 
from where it is, the extended surface has to yield to the 
resulting compression by folding more than it would have 
had to do had there been no molten intrusions in the first 
place. It is, therefore, reasonable to call this the first step in 
mountain building, although there is as yet no folding, and 
no uplift of the rock strata. 

But this question of molten intrusions into the crust raises 
another sore point. It has been, until now, a very difficult 
thing to explain the rise of molten matter into the crust. 
Geologists have speculated as to what force could have shot 
up the molten matter that formed the innumerable "dikes" 
and "sills," as the resulting veins are called. They have not 
been able to agree upon the question. No reasonable ex- 
planation of these millions of magmatic invasions of the crust 
has been found. 

Of course, it is realized that the crust of the earth is, in a 
sense, a floating crust. The materials of which it is composed 
are lighter, it is assumed, than the materials below, and are 
solid, as compared with the plastic or viscous state of the 
underlying layers. The crust can be thought of as floating 
in hydrostatic balance in the semiliquid lower layer. This is 
generally understood among geologists. It follows logically 
from this that, if two or more blocks of the crust got sepa- 
rated with cracks between them, the "molten" material 



THEMOUNTAINS 99 

would rise in the crack, and the blocks would sink, until the 
cracks weie filled up far enough to establish hydrostatic bal- 
ance. But this did not solve the problem; it did not help 
because nobody could imagine what could produce the neces- 
sary pulling apart of the blocks. 

For those who like to see complicated problems made sim- 
ple, Mr. Campbell's presentation of this matter is worth 
considering. He suggests that the concept of a great sector 
of the crust being stretched, and thereby fractured in in- 
numerable places at one time, permits a comparison to be 
made with an ice sheet, which is floating on water, and which 
undergoes fracturing. Just as the individual pieces of the ice 
floe sink, until they have displaced their weight in water, 
and the water rises in the cracks between the pieces, so he 
visualizes the behavior of the crust during its displacement 
equatorward. He sees this as the explanation of the fact that 
although the crust is shot through with igneous invasions of 
all sorts, these are hardly ever known to reach the surface of 
the earth. He compares the behavior of the crust during dis- 
placement with the behavior of ice as follows: 

... As a matter of fact the lithosphere (or crust) can be likened to 
ice floating on water, a solid and lighter form of a substance floating 
in a liquid and heavier form of a similar substance. The solid and 
lighter substance sinks in the heavier and liquid substance until it 
displaces its own weight in the heavier and liquid substance and then 
floats with its surplus bulk above the surface of the heavier liquid, 
which in the case of ice would be one tenth of its bulk. To put it 
another way, if you were out on a lake where the ice was ten inches 
thick, and you were to bore a hole through the ice to the water, the 
water would rise in the hole to within one inch of the surface of the 
ice and remain there. Now, that is exactly what happens to the litho- 
sphere. It sinks into the asthenosphere (or subcrustal layer) until it 
displaces its own weight of the substance of the asthenosphere and a 
state of equilibrium is reached. That will bring the substance of the 
asthenosphere far up into the lithosphere, wherever it finds an open- 
ing or a fault that reaches all the way to the bottom of the litho- 
sphere (66). 

Purely for purposes of illustration, and not as an accurate 



100 EARTH S SHIFTING CRUST 

picture of the facts, Mr. Campbell has made a very rough 
calculation, as follows: 

Assuming that the lithosphere is composed of granite that has a 
weight of 166 pounds to the cubic foot, and the asthenosphere con- 
sists of soapstone with a weight of 169 pounds per cubic foot, the 
lithosphere being three pounds lighter per cubic foot than the 
asthenosphere, it would float in the heavier asthenosphere leaving 
1.775% of its volume above the surface of the asthenosphere, and as 
the lithosphere is assumed to be forty miles deep in this case, then 
1.755% of forty miles would be .71% of a mile above the top of the 
asthenosphere. That is, the soapstone molten asthenosphere would 
rise up into the fault to within three quarters of a mile of the surface 
of the earth. . . . (66). 

Summarizing his general thoughts regarding the effects of 
an equatorward displacement of a crustal sector, and the 
hydrostatic balance of the crust itself, Mr. Campbell has 
remarked: 

I think you should stress this point, for, while the geophysicists 
have seen faults in the earth's crust, and have seen many of these 
faults that they knew had been filled up from below, they didn't have 
any logical solution of what caused the faults, nor did they connect 
the faults with the formation of our mountains (66). 



5. The Effects of Poleward Displacement 

In the poleward displacement of sectors of the crust, com- 
pression, instead of extension, would be the rule. The mag- 
nitudes and the distribution of forces, and the time element, 
would, of course, be the same. Otherwise, the effects would 
be very different. 

We should have, in the first place, some folding of the 
rock strata. As with the fractures, the precise locations of the 
rock foldings, their number, and their magnitudes would be 
controlled by the amount of the displacement locally, the 
local variations of crustal strength (which would be less 
where geosynclines already existed), and the distances of the 
areas concerned from the central meridian of movement. 



THE MOUNTAINS 1O1 

The amount of the folding would be increased as the result 
of any previous process of extension of that area of the crust 
in any previous displacement. 

The elastic properties of the crust would probably be of 
much greater importance in this compressive phase than in 
the extensive phase of a displacement. This is because com- 
pression could lead to flexing or bending of the crust, to a 
slight degree, without a permanent change of shape. It might 
be possible to bend or flex the crust slightly, and hold it so 
for thousands of years, without fracture or folding of the 
rock strata, or even without much plastic flow of the ma- 
terials. This would mean no permanent change in the con- 
formation of the surface. A compressive tension might be 
exerted for thousands of years, causing a flexing, and then 
be relaxed, permitting the crust to return to its original 
shape. It may be supposed that in areas sufficiently removed 
from the meridian of maximum displacement, the com- 
pressive tensions on the crust might be contained by its ten- 
sile strength, and the crust might yield elastically, without 
deformation. If this occurred, however, the total amount of 
the compression for the whole circumference of the globe 
would probably be concentrated at comparatively few points, 
where the compressive stresses happened to be in excess of 
the strength of the crust; here there would be a considerable 
amount of folding of the rock strata. It is obvious, also, that 
these points would tend to coincide with existing geosyn- 
clines, which would naturally represent comparatively weak 
zones, where the crust would be less able to withstand the 
horizontal stress. 

Mr. Campbell suggests that in an area displaced poleward, 
no fewer than four pressures will be operating simul- 
taneously on the crust. There will be, in the first place, two 
pressures developing from opposite directions toward the 
meridian of displacement. These will arise because of the 
diminishing circumference. Two other pressures will simul- 
taneously develop at right angles to these, as the result of the 
reduced radius. Since the radius is only one sixth of the cir- 



IDS EARTH'S SHIFTING CRUST 

cumference, the forces will be in proportion; the folds due 
to the first compression will tend to be six times as long (and 
accentuated) as those due to the second compression. The 
former may ultimately correspond with the long axes of 
the mountain ranges, and the latter to their radial axes. The 
long, narrow, folded tracts referred to by Button are thus 
explained. 

In Figure II Mr. Campbell has suggested an idealized rep- 
resentation of the formation of a mountain chain by a dis- 
placement of the crust. The reader will note the long major 
axis, and the shorter radial axes. That this is a fairly close 
approximation to the patterns of existing mountain ranges 
is obvious; however, a number of modifying factors must be 
recognized. In the first place, we do not contemplate that a 
mountain range can be completed in the course of one move- 
ment of the crust. It is quite obvious, from the quantitative 
considerations already mentioned, that a single displacement 
could cause comparatively little folding, even if, as the result 
of elastic yielding, most of the folding was concentrated in a 
few areas. It is certain that many displacements would be re- 
quired to make a large mountain range, and since successive 
displacements will not necessarily occur in the same direc- 
tions on the earth's surface, the resulting patterns might 
rarely conform to the idealized pattern. And yet, if most of 
the folding in one displacement happened to be concen- 
trated in one area, and if one or more successive displace- 
ments happened to concentrate folding in the same area, a 
mountain range might come into existence in a compara- 
tively short period of two or three hundred thousand years. 
We will return to this chronological aspect again. 

It should not be thought that Mr. Campbell is in disagree- 
ment with Button's statement, quoted above, that the com- 
pressive mountain-folding forces have acted in one direction 
only on the earth's surface. This would be a misunderstand- 
ing of the case. The laws of physics require the operation of 
equal and opposite forces for the production of effects. A 
compression is the result of two equal and opposite pressures. 



THE MOUNTAINS 



There is still one definite direction, such as northeast-south- 
west, in which the compression operates on the crust. 



4. The Mountain-Building Force 

An apparently formidable objection that has been raised to 
this theory of mountain formation is that the force pro- 
vided by the icecaps cannot be sufficient. When you look at 
the towering summits of the Sierras from your speeding 
plane, and your eye takes in the numberless peaks fading 
away into the far horizon, you are impressed by the thought 
of the enormous force that must have been required to raise 
this great chain of mountains. How could all this have been 
the result of a gentle pressure applied to the crust of the 
earth by distant icecaps? 

Campbell has shown that the apparent discrepancy be- 
tween the cause and the effect, here, is the result of a misap- 
prehension as to the identity of the actual force responsible 
for the mountain folding. His calculations (given and dis- 
cussed in Chapter XII) show that the thrust transmitted to 
the lithosphere by the icecap is of the right order of magni- 
tude to bring about the fracturing of the crust. The icecap 
may therefore be responsible for the movement of the crust; 
yet it is not the force directly responsible for the folding of 
the mountains. The latter is a much greater force. Mr. Camp- 
bell shows that the mountain-folding force is none other than 
the force of gravity itself. He suggests that the icecap per- 
forms the function merely of sliding the crust horizontally 
to a place where the force of gravity can act upon it. When 
an area is moved toward a pole, where the radii of the earth 
are shorter, circumference is shorter, and surface required is 
less, there is a surplus of surface, and this, being pulled down 
by gravity, must fold. From this point of view, it appears that 
the mountains are not pushed up at all, and therefore, no 
lifting force is required; instead, it is the surface of the earth 
that is pulled down, by gravity, nearer to the earth's center, 



104 EARTH'S SHIFTING CRUST 

as a sector of the crust approaches a pole. Where this hap- 
pens, the surplus surface must fold. Thus it is the force of 
gravity, over a large area, that folds the crust in a small area. 

It may help the reader to grasp this idea if he will visualize 
a flat area on the equator which, in process of being displaced 
with the crust as far as a pole, has been folded enough to pro- 
duce mountains six miles high. Now, actually, the peaks of 
those mountains are no farther from the center of the earth 
than the flat area was at the equator. Their altitude, with 
reference to the earth's center, is unchanged. What has 
changed altitude, however, is the rest of the surface, outside 
the mountain chain. That has been pulled down six miles. 
What pulled it down, obviously, was the force of gravity, and 
the reason it was pulled down was that it was first shifted 
horizontally to a place where gravity could act upon it. 

Here, then, is the answer to the long-standing enigma of 
the source of the energy for mountain folding. The moun- 
tains are not lifted up at all; the surface is pulled down, the 
force of gravity does the pulling, and folding results where 
there happens to be excess of surface. 



JF. Existing Fracture Systems as Evidence for the Theory 

It is ordinarily considered a strong argument in favor of 
a hypothesis if it enables one to anticipate the discovery of 
phenomena. Campbell has shown that the theory of displace- 
ments of the earth's crust calls for the existence of great sys- 
tems of parallel fractures, intersected by other fractures at 
right angles to them. It was some time after Mr. Campbell 
began to consider this matter, and quite independently of 
him, that I became aware of the fact that such fracture pat- 
terns do, in fact, extend over the whole face of the globe, 
and that geologists are in agreement that their origin is un- 
explained. Many years ago Hobbs pointed out that they 
must have been the result of the operation of some world- 
wide force: 



THE MOUNTAINS 105 

The recognition within the fracture complex of the earth's outer 
shell of a unique and relatively simple pattern, common to at least 
a large portion of the surface, obscured though it may be in local dis- 
tricts through the superimposition of more or less disorderly fracture 
complexes, must be regarded as of the most fundamental importance. 
It points inevitably to the conclusion that more or less uniform con- 
ditions of stress and strain have been common to probably the earth's 
entire outer shell (217:163). 

As I have pointed out, Mr. Campbell's projected pattern 
of fractures is a sort of gridiron, with major fractures paral- 
leling the meridians, and minor fractures at right angles to 
them. In the actual earth's surface, however, there are two 
such patterns. One of them consists of north-south fractures 
paralleling the meridians, intersected by east-west fractures 
paralleling the equator. The second gridiron is diagonal to 
the first; the lines run northeast-southwest, and northwest- 
southeast. As to why there should be two such distinct frac- 
ture complexes in the crust, I shall have more to say later on. 
Hobbs insists that the existence of these world-wide patterns 
points to a cause acting globally; they could not have been 
the result of local causes; the force causing the fracturing 
must have acted simultaneously, so to speak, over a great 
part of the whole surface of the earth: 

. . . The results of this correlation possess considerable significance 
inasmuch as it is clear that over quite an appreciable fraction of the 
earth's surface, the main lines of fracture betray evidence of common 
origin. . . . (218:15). 

The fracturing of the crust under the operation of some 
global force has been accompanied by much tilting and rela- 
tive movement of blocks of considerable size, resulting in the 
alteration of topographic features. One of the earlier geolo- 
gists, Lapworth, remarked with considerable truth, though 
also with some exaggeration, that 

On the surface of the globe this double set of longitudinal and 
transverse waves is everywhere apparent. They account for the de- 
tailed disposition of our lands, and our waters, for our present coastal 
forms, for the direction, length and disposition of our mountain 
ranges and plains and lakes (430:296). 



io6 EARTH'S SHIFTING CRUST 

It is clear, I think, from what has already been said, that 
Lapworth was in error in ascribing the folded mountains to 
the effects of fracturing alone. However, it may well be that 
formation of block mountains, such as the Sierra Nevadas, 
can be accounted for in this way. Innumerable other features 
of the crust have been formed or obviously much affected 
by the fracture patterns. Hobbs, for example, has maps of 
river systems in Connecticut and Ontario, showing how 
closely the rivers and their tributaries follow the lines of the 
fracture systems (216:226). Many river beds, many submarine 
canyons, were never created by subaerial erosion; they were, 
instead, the results of deep fractures in the crust, later occu- 
pied by rivers or by the sea. On the land erosion no doubt 
often, if not usually, completed the shaping of the valleys, 
while turbidity currents may have created or deepened can- 
yons in the unconsolidated materials of the ocean bottom 

037> 139* M )- 

A succession of theories to account for the world-wide or 

"planetary" fracture patterns has been developed and re- 
jected. As soon as it became clear that these patterns could 
not be explained as the result of local forces, the problem 
was recognized as very formidable. Sonder, a Swiss geologist, 
attempted to explain them as the result of a difference in the 
compressibility (or elasticity) of the rocks of the continents 
as compared with those under the oceans. But Umbgrove 
pointed out that this would call for independent fracture 
systems for each of the continents, whereas existing fracture 
patterns extend to several continents (430:300-01). 

The Dutch geologist Vening Meinesz suggested that the 
fracture patterns could be explained mathematically by a 
displacement of the crust of the earth. He postulated one 
displacement about 300,000,000 years ago, through about 70 
of latitude (194:204^. Umbgrove rejected this theory be- 
cause he saw that there were many features of the earth's sur- 
face that could not be explained by the particular displace- 
ment suggested by Vening Meinesz. This is not at all 
remarkable, since it is quite impossible to see how any one 



THE MOUNTAINS 107 

displacement, and particularly one 300,000,000 years ago, 
can be made to explain most of the earth's present topo- 
graphic features. Umbgrove was justified in rejecting the 
Vening Meinesz theory, but he admitted that this left him 
with no explanation at all. "... On the other hand, it means 
that the origin of both lineament systems remains an un- 
solved problem" (430:307). 

Some writers have suggested that the two fracture systems 
originated at different times, and this is a very important 
point. Umbgrove says: 

It is a rather widespread belief that the origin of faults with a cer- 
tain strike dates from a special period, whereas faults with a markedly 
different strike would date from another well-defined period. In cer- 
tain areas this conviction is founded upon sound arguments. . . . 
(430:298). 

He continues: 

Some authors, however, have doubtless overrated the relation be- 
tween the direction and the time of origin of a fault system. As a 
typical example, I may mention Philipp, who once advanced the 
opinion that the direction of the principal fault lines of northwestern 
Europe changed from W. and W.N.W. in the Upper Jurassic toward 
N. or N.N.E. in the Oligocene, and thence E.N.E. in the upper 
Tertiary and Pleistocene. He added the hypothesis that their rotation 
could have been caused by a large displacement of the poles. In the 
meantime it has been shown that some faults with a meridional strike 
date from much older periods. Moreover, large and well-defined 
faults with a N.N.W. direction dating at least from the Upper Paleo- 
zoic appear to have been of paramount influence in the structural 
history of the Netherlands. Therefore Philipp's hypothesis has to be 
abandoned because it is inconsistent with well-established facts (430: 
298). 

Abandoned much too soon! The reader can easily see that 
the objections Umbgrove raises to Philipp's theory are re- 
moved by the present theory of crust displacements. With 
this assumption, it would be inevitable that, in the long his- 
tory of the globe, the poles would often be found in about 
the same situations. If the strikes of the fault systems are 
related to the positions of the poles, those of later periods 



io8 EARTH'S SHIFTING CRUST 

would often coincide approximately with those of earlier 
periods. 

We find in this very fact the answer to another of the mys- 
teries of geology, the so-called "rejuvenation" of similar fea- 
tures in the same geographical situations at various times. 
The term "rejuvenation" is a commonplace of geological 
literature, and is especially emphasized by Umbgrove. He 
is puzzled by the fact that old geological features have re- 
peatedly been called back to life. It seems that this renewal 
of old topographies may be explained by the accidental re- 
turn of the poles to approximately the same places. 

There is nothing remarkable about the fact that only two 
world-wide fracture systems can now be recognized in the 
crust. If each successive displacement produced a new grid- 
iron pattern of fractures and resulting surface features, it 
must, in addition, have disrupted the evidence of previous 
patterns. In a long series of displacements, the older frac- 
ture patterns must soon be reduced to an indistinguishable 
jumble. It is probable that the two systems now recognizable 
date only from the last two displacements of the crust (to be 
discussed later), even though many of the fractures and indi- 
vidual topographic features now coinciding with these sys- 
tems may date from remote periods. 

It is not true, of course, that in one displacement of the 
crust all fractures all over the earth will form a single rec- 
tilinear pattern. This can be made clear from an example. 
Let us suppose (as we shall in Chapter VII) that North Amer- 
ica was moved directly southward at the end of the last ice 
age. Campbell has suggested that major fractures would run 
north and south (meridionally) and minor fractures east and 
west, and this would be true of the whole Western Hemi- 
sphere, which was, presumably, moved southward, and of 
the opposite side of the earth, which was equally displaced 
northward. But what about Europe? If, before the last dis- 
placement, the pole was situated in or near Hudson Bay, it 
seems that the last displacement must have created diagonal 
and not meridional fractures in Europe, for the reason that 



THE MOUNTAINS 

Europe was nowhere near the meridian of displacement. 
Thus, in one given displacement, a meridional fracture pat- 
tern will be created near the meridian of displacement, a 
diagonal fracture pattern in very large areas approximately 
4.5 degrees from this meridian, and, of course, no fracture 
pattern in the ''pivot" areas, 90 degrees from the meridian of 
displacement, where no displacement will occur. 

Lately, the oceanographic research work under the direc- 
tion of Ewing has resulted in tracing a globe-encircling crack 
in the bottoms of the Atlantic, Indian, and Pacific Oceans, 
and has connected it with the Great Rift Valley in Africa. 
The pattern that has been traced out is about 40,000 miles 
long; it is reported that there is seismic activity at present 
along the whole length of the crack, suggesting recent dis- 
turbance of the area and a still-continuing process. The 
crack appears to average two miles in depth and twenty miles 
in width. The fact that it is connected with the Rift Valley 
in Africa, that it bisects Iceland, and apparently invades 
Siberia, indicates that it is not a phenomenon of ocean ba- 
sins only. It is, on the contrary, clearly a global phenomenon. 
The Columbia Research News, published by Columbia Uni- 
versity, in its issue of March, 1957, described the discovery 
thus: 

In January, Columbia University geologists announced the dis- 
covery of a world-wide rift believed to have been caused by the pull- 
ing apart of the earth's crust. The big rift traverses the floors of all 
the oceans and comes briefly to shore on three continents in a system 
of apparently continuous lines . . . 45,000 miles long. 

Throughout its vast length the world-wide rift seems to be remark- 
ably uniform in shape, consisting of a central valley or trench aver- 
aging 20 to 25 miles in width and flanked on either side by 75 mile- 
wide belts of jagged mountains rising a mile or two above the valley. 
The peaks of the highest mountains in the system are from 3,600 to 
7,200 feet below the ocean's surface while the long undersea stretches 
of the rift valley itself lie from two to four miles down. In addition 
to being marked by its topography, the globe-circling formation is 
the source of shallow earthquakes that are still going on along its 
entire length an indication that, if the rift is due to a pulling apart 
of the earth's crust, the geological feature is a young and growing one. 



110 EARTH S SHIFTING CRUST 

What could be the cause of such a pulling apart of the 
crust? Surely not a shrinking and cooling of the earth. It is 
also very unlikely, it will be admitted, that the earth could 
be growing fast enough to produce this split and the accom- 
panying geological instability. On the other hand, a displace- 
ment of the crust, or rather a series of them, may explain the 
facts. It even appears that here, in this system of profound 
cracks in the crust, we have evidence of the existence of zones 
of crustal weakness along which, perhaps time and again, the 
splits have occurred that have permitted the displacement of 
the crust, and at the same time have relieved some of the 
resulting tension and thereby limited the tectonic conse- 
quences of the displacements so far as other areas of the 
earth's surface are concerned. 

To return briefly to the question of block mountains, Mr. 
Campbell has a further suggestion as to the way in which 
compression in a poleward displacement, and subsequent 
fracturing, may combine to cause them. One of the problems 
that awaits solution in geology is the cause of the widespread 
doming and basining of the crust that occurs from place to 
place. The domes are sometimes of considerable extent. Ex- 
amples of basins include the Gulf of Mexico and the Caspian 
and Black Seas. Campbell points out that if an area is dis- 
placed poleward, and is thereby subjected to four compres- 
sions, as already mentioned, limited areas will be entrapped 
by these compressions, and doming must result; conversely, 
in areas moved equatorward the reverse must occur, and 
larger or smaller basins will tend to be produced. 

A block mountain might tend to be produced, Mr. Camp- 
bell thinks, if a major fault should bisect a domed-up area. 
This would create the possibility that the abutting rock sec- 
tions of one half of the dome might give way, allowing half 
the dome to collapse, and pushing subcrustal viscous or plas- 
tic rock under the other half of the dome, thus rendering 
the latter permanent. This effect, however, would depend 
upon many local circumstances. 



THE MOUNTAINS 111 



PART II. Volcanism and Other Questions 

In the preceding part of this chapter we have sketched the 
principal problems that are basic to the formation of the 
folded mountains and block mountains, and have examined 
the planetary fracture systems in the light of Campbell's 
mechanism for crust displacement. There are, however, a 
number of other aspects of this general problem that must 
now engage our attention. We must consider, in turn, the 
remarkable phenomena of volcanism, in their relationship to 
crust displacement. In connection with the creation of vol- 
canic mountains we must consider briefly the question of the 
origin of the heat of the earth, an unsolved problem of great 
interest. We must then examine the relationship of crust 
displacement and mountain building to the question of 
changes in the sea level. Finally, we must consider the prob- 
lem of the chronology of mountain building. 



6. Volcanism 

We have seen that one kind of mountain is the volcanic 
mountain. Volcanic phenomena cover a wide range; all of 
these must be considered in order to see how far they can be 
related to a general cause. The phenomena that need ex- 
plaining include volcanic eruptions, the creation (sometimes 
rapid) of volcanic mountains on land or in the sea, the gene- 
sis of volcanic island arcs, and last but not least the vast lava 
flows or lava floods that have at times in the past inundated 
great areas of the earth's surface. 

Since volcanoes occur frequently, and are the most 
dramatic manifestations of volcanism, they have been thor- 
oughly studied, and a whole literature has been devoted to 
them. It is astonishing, therefore, that neither the causes of 
volcanoes nor the present distribution of volcanic zones on 



112 EARTH'S SHIFTING CRUST 

the earth's surface has as yet received an acceptable explana- 
tion. As in the case of other unsolved problems, the absence 
of certainty has led to a multiplicity of theories. Jaggar, one 
of the best field observers of volcanoes, refers to the two 
leading theories thus: 

It would be hard to imagine any more completely different ex- 
planations for the same phenomenon than is R. A. Daly's doctrine of 
the causes of volcanic action, as compared with the crystallization 
theory of A. L. Day (235:150). 

Dr. A. L. Day was formerly director of the Geophysical 
Laboratory in Washington; his theory is based upon geo- 
physical experiments conducted in the laboratory. He ob- 
served that the crystallization of rock from the molten state 
resulted in some increase in volume. He assumed that the 
whole crust was once molten, and that as it cooled it contin- 
ued to contain, here and there, comparatively small pockets 
of molten rock. When such pockets of molten rock finally 
were cooled to the crystallization point, then expansion 
would occur, and great pressures would be set up, which 
might lead to eruption at the surface. This theory is based 
upon the assumption of the molten origin of the earth, and 
carries with it the corollary that volcanic eruptions are essen- 
tially local phenomena. Dr. Day insisted that volcanoes were 
not connected with a molten layer under the crust, and were 
not related to events occurring over large areas. 

Professor R. A. Daly based his opposed theory on his ob- 
servations of the field evidence of geology. He insisted that 
only the assumption of a molten layer under the crust could 
account for the countless facts of igneous geology. His theory 
is reconcilable either with the assumption of the molten ori- 
gin of the globe or with the theory of a growing and heating 
earth. 

Jaggar objects to Day's view that volcanoes are purely lo- 
cal. He says: 

There is some reason to think that a very long crack in the bottom 
of the Pacific Ocean, with interruptions by very deep water, extends 



THE MOUNTAINS 11$ 

all the way from New Zealand to Hawaii, because there are striking 
sympathies of eruptive data between the volcanoes of New Zealand, 
Tonga, Samoa and Hawaii (235:23). 

He lists a number of eruptions with their dates to show their 
intimate connection. In particular he mentions the eruption 
of August 31, 1886, on the island of Niuafoo, Polynesia: 

. . . Only two months before, Tarawere Volcano was erupted dis- 
astrously in New Zealand, indicating volcanic sympathy between two 
craters hundreds of miles apart on the same general rift in the earth's 
crust (235:95). 

These observations imply that a connection may exist, at 
least in some cases, between volcanoes at great distances from 
each other, because of their being located along the same 
crack in the earth's crust. This implies a connection between 
the deep fracturing of the earth's crust and volcanism. We 
have seen that Columbia scientists have just discovered a 
vast connected system of rift valleys, or cracks in the crust, 
extending over the surface of the whole planet, and associ- 
ated at the present time with constant seismic disturbances. 
Jaggar makes it clear that volcanic eruptions, as well as earth- 
quakes, may be associated with such rifts. Since the crust is 
relatively thin, it is reasonable to suppose that the molten 
rock erupting in volcanoes at great distances from each other 
must come from below the crust, and that it is not created 
by any processes occurring within the crust itself. All this is 
confirmation of Daly's position. 

Another theory of volcanic action that should be men- 
tioned briefly is that associated with the name of W. H. 
Hobbs. It was his view that volcanic action could result from 
horizontal pressure arching up a sector of the crust. This is 
based on the fact that if a rock that is too hot to crystallize at 
normal pressures is subjected to great pressure, it may take 
the solid state. Subsequently, the release of the pressure is 
all that is required to restore the rock to its liquid con- 
dition. In the earth's crust considerable amounts of rock 
may be held in the solid state by the pressure of overlying 
strata. Then, if horizontal pressure arches the crust, the 



ii4 EARTH'S SHIFTING CRUST 

pressure on the rock below will be relieved, and the rock 
will resume a liquid state. If the arching results in cracking 
at the surface, or in sufficient lateral squeezing of the liquid 
pockets, eruption may take place. This effect may account for 
the vast masses of igneous rock that are found associated with 
the folded mountain ranges (215:58), but it is necessary to 
ask the question, What causes the arching of the crust? Ob- 
viously, volcanism, according to this theory, must be traced 
to the cause of the arching. Hobbs's theory is not very satis- 
factory because he cannot explain the arching. 

It is clear that volcanism might occur as the result either 
of the process imagined by Day or of that imagined by Hobbs, 
for several different causes might produce liquid pockets in 
the crust. But it is equally clear that neither they nor Daly 
has advanced a theory to account for volcanoes, volcanic 
zones, plateau basalts, and volcanic mountains. Einstein, 
when he first received some material outlining the theory 
proposed in this book, wrote me that it was the only theory 
he had ever seen that could explain the volcanic zones (128). 
These, of course, can be explained as zones of fracture (such 
as the rift valleys just mentioned) resulting from crust dis- 
placements. 



7. The Volcanic Island Arcs 

Campbell has suggested an explanation for the formation 
of the volcanic island arcs, so many of which are found in 
the Pacific, and which consist of chains of volcanic moun- 
tains in the sea. He shows not only how our theory of crust 
displacement may account for the formation of these vol- 
canic mountains but also how it may account for their oc- 
currence in graceful curves: 

As a sector of the lithosphere, or crust, moves toward the equator, 
the motion is fastest and the tension is greatest on the meridian of 
movement, and great north-south faults will open up, beginning 
there and spreading east and west. At the same time transverse faults 



THE MOUNTAINS 117 

of the earth. Smart, for example, is of the opinion that radio- 
activity cannot produce heat in the earth as fast as it can be 
radiated through the crust into outer space (396:62). 

Some of the essential facts in any consideration of the 
question of the origin of the earth's heat may be summarized 
as follows. First, we know nothing of the temperature of 
the earth's interior. We can only guess at it. We have made 
deductions concerning it from the heat gradient observed 
in the world's deepest mines. As we descend to a depth of 
about four miles, the heat steadily increases (194:139). We 
have assumed that the increase of heat continues at the same 
rate farther down, perhaps all the way to the earth's center, 
but there are a number of facts that throw doubt on this 
assumption. For one thing, Daly thought he saw evidence 
that the heat gradient differs in America and in Europe, 
being somewhat steeper in North America (194:139). This 
would imply that there is more heat in the earth's crust in 
North America than there is in Europe. Benfield produced 
much more evidence of variations in heat from place to 
place (28) which are difficult to reconcile with a uniform heat 
gradient in the earth. 

Geophysicists have now concluded that the earth's heat 
originates in the crust itself, and does not come from the 
deep interior (194:157). The considerations on which this 
conclusion is based are too technical for discussion here, but 
there seems to be no reason to doubt their validity. This con- 
clusion is, of course, irreconcilable with any assumption that 
the earth's heat is simply the remnant of far higher tempera- 
tures prevailing in a molten stage. 

A matter of great importance for the general problem is 
the rate at which heat migrates through the crust, and is 
dissipated into outer space. Geophysicists have determined 
that the rate of heat migration through the crust is extremely 
slow. Jeffreys calculated that it would take 130,000,000 years 
to cool a column of sedimentary rock 7 miles below the 
earth's surface by 250 C. (241:136). As a result of this, 
the climate of the earth's surface is determined entirely by the 



n8 EARTH'S SHIFTING CRUST 

radiant heat of the sun, and is uninfluenced by heat from 
within the earth. We shall have to consider the bearing of 
this on another well-known fact, which is that earthquakes, 
and other movements within the crust, are known to produce 
heat as a consequence of friction between the moving crustal 
blocks (194:158). Then, earthquakes are most frequent in 
areas where there are distortions of the gravitational balance 
of the crust, while heat gradients are steeper in such areas 
(194:141). This indicates that any factor causing such distor- 
tions may be a factor in the production of the earth's heat. 

Considering these facts, what are the implications, so far 
as the earth's heat is concerned, of a displacement of the 
earth's crust? Can there be any doubt that a crust moving 
slowly over a period of a good many thousand years must 
generate an immense quantity of heat within itself? There 
can be no doubt of this. The widespread fracturing, the fric- 
tion between crustal blocks, resulting from the increased 
number of earthquakes, could have no other result. More- 
over, Frankland has pointed out that friction between the 
crust and the layer over which it moves must produce heat, 
which may itself facilitate the displacement (168). 

The heat thus produced would migrate both inwards into 
the body of the earth and outwards into space. But, since the 
rate of dissipation of this heat is so extremely slow, it follows 
that displacements at relatively short intervals might pro- 
duce heat more rapidly than it could be dissipated. Over 
hundreds of millions of years slight increments of heat from 
this source may have accumulated to produce the earth's 
present temperature. The assumption of frequent crust dis- 
placement thus suggests a third possible source of the earth's 
heat, in addition to those mentioned by Gutenberg. 

If it is true, as Daly thought, that the heat gradient is 
steeper in North America than in Europe, this fact serves 
as additional confirmation of a displacement of the earth's 
crust at the end of the Pleistocene. Later I shall present evi- 
dence to suggest that the crust moved at that time in such 
a direction as to bring North America down from the pole 



THE MOUNTAINS 

to its present latitude. If this occurred, it meant a displace- 
ment of about 2,000 miles for eastern North America, but 
of only about 500 miles for western Europe. Quite obviously, 
crust adjustments and resulting friction must be propor- 
tional to the amount of the displacement, and therefore fric- 
tion and resulting heat could be expected to be somewhat 
greater in America. 

To return, now, to our plateau basalts, we may observe 
that, in a situation where the crust of the earth was con- 
tinuously in motion over an extended period, a build-up 
of heat in the crust might cause considerable melting in its 
lower parts where the temperature was already very close to 
the melting points of the rocks. This increase of heat would 
link itself quite naturally, therefore, to an increase in the 
number and intensity of volcanic eruptions, and to lava flows 
of all kinds. By means of these eruptions and flows some of 
the heat would be dissipated into the air; much of it, how- 
ever, imprisoned in the lower part of the crust, would simply 
increase the volume of the molten magmas. 

While the increase of heat in the crust would naturally 
favor larger lava flows, another factor would create the pos- 
sibility of massive flows, or lava floods. A massive displace- 
ment of the crust, because of the oblateness of the earth, 
must produce temporary distortions of its shape, and of the 
gravitational balance of the crust. The force of gravity sub- 
sequently must gradually force the crust to resume its normal 
position. This, of course, involves great pressure upon the 
crust, and upon the molten or semimolten liquid material 
under or within the crust. Pressures of this kind might oc- 
casionally lead to the eruption of plateau basalts. The prob- 
able magnitude of the distortions of the crust resulting from 
displacement will be considered in detail later on. It must 
not be supposed, however, that every displacement of the 
crust must inevitably produce lava floods. The latter would 
perhaps be the result of an unusual combination of pressures 
and fractures. The same combination of forces which might, 
in one situation, produce volcanic mountains and island arcs 



i2o EARTH'S SHIFTING CRUST 

might, under other circumstances, produce a doming up of 
the crust in a local area or a lava flood. 



p. Changing Sea Levels 

An important problem closely related to that of mountain 
building is that of the cause of very numerous, and in some 
cases radical, changes in the elevations of land areas rela- 
tively to the sea level. Umbgrove finds that mountain folding 
has been related, in geological time, with uplift of land areas, 
or with withdrawal or regression of the sea (430:93). How- 
ever, it is clear that the uplifts were not confined merely to 
the folded areas, that is, to the mountains themselves, but 
affected large regions. Such uplifts, where whole sections of 
the earth's crust were elevated without being folded, are re- 
ferred to as epeirogenic uplifts, to distinguish them from the 
uplifts of the folded mountain belts which may have re- 
sulted from the folding itself, and which are referred to as 
orogenic uplifts. As to the extent of the resulting changes in 
sea level, Umbgrove says: 

. . . The most important question concerns the depth to which 
the sea-level was depressed in distinct periods of intense regression, 
in other words, the extent of the change to which the distance be- 
tween the surface of the continents and the ocean floors was subjected 
during the pulsating rhythm of subcrustal processes. Joly was the 
only one who approached this question from the geophysical side, 
and he arrived at an order of 1000 meters. . . . (430:95). 

It becomes necessary, therefore, to find a connection be- 
tween the cause of the folding of the crust and the cause of 
general, or epeirogenic, changes of elevation of continents 
and sea floors. Fortunately, this problem is not really so diffi- 
cult as it may seem at first glance. That it can be solved in 
terms of the assumption of displacements of the earth's crust 
is, I think, clear from the following considerations. 

Gutenberg has pointed out that if a sector of the crust, in 
gravitational equilibrium at the equator, is displaced pole- 



THE MOUNTAINS 121 

ward by a shift of the whole crust, it will be moved to a 
latitude where gravity is greater, because gravity increases 
slightly toward the poles. Its weight will be thereby in- 
creased, and to remain in gravitational equilibrium it must 
seek a lower level: it must subside. The water level in the 
higher latitude adjusts easily, of course. Gutenberg points out, 
however, that if the movement of the crust occurs at a rate 
greater than the rate at which the sector may sink, by dis- 
placing viscous material from below itself, the result will be 
that the sector will stand (for a time) higher relatively to sea 
level than it did before. I give Gutenberg's own words: 

Movements of the earth's crust relative to its axis must be accom- 
panied by vertical displacements. A block with a thickness of 50 
kilometers in equilibrium near the equator should have a thickness 
of 49.8 near the poles to be bounded by the same equipotential sur- 
faces there. If it moves toward a pole, it must sink deeper to keep in 
equilibrium. If the process is too fast for maintenance of isostatic 
equilibrium, positive gravity anomalies and regressions are to be ex- 
pected. Thus regression may be an indication that an area was moving 
toward a pole, and transgressions that it was moving toward the 
equator (194:204-05). 

According to Gutenberg, an area moved about 6,000 miles 
from the equator to a pole would stand about 1,200 or 1,400 
feet higher above sea level, if the speed of the displacement 
was too rapid for maintenance of gravitational equilibrium. 
The speed of displacement that is suggested by the evidence 
to be presented later is such as to eliminate entirely the 
possibility that the crustal sector could sink and remain in 
gravitational equilibrium. Consequently, by our theory, a 
poleward movement of any sector of the crust will result in 
uplift, and in regression of the sea. In addition, it appears 
to me that since any sector displaced poleward would also 
be compressed laterally, this would offer another obstacle to 
its subsidence. It would have to overcome the lateral pres- 
sures, as well as displace underlying material. 

The amount of the uplift of an area displaced poleward 
would depend, of course, on the amount of the displacement. 
As will be made clear later, much geological evidence ap- 



122 EARTH'S SHIFTING CRUST 

pears to suggest that displacements may have amounted, on 
the average, to no more than a third of the distance from a 
pole to the equator. If this is true, then the resulting uplift 
to be expected should be of the order of about one third of 
the uplift he suggested, or from 400 to 500 feet. We shall see, 
later, how well this agrees with the evidence. 

There is another factor that would operate in the same 
direction as the effect mentioned by Gutenberg, to alter the 
elevation of land areas and sea bottoms. Unlike the gravita- 
tional effect, however, this second factor would tend to a 
permanent change in sea levels, and might therefore, cumu- 
latively, result in important changes in the distribution of 
land and sea. It is a question of the permanent consequences 
of the stretching or compression of the crust. As we have 
seen, an area displaced poleward must undergo compression 
because of the shortened radius and circumference of the 
earth in the higher latitudes. This compression must result 
in the folding of rock strata, which will be likely to occur 
mainly in areas where the crust has already been weakened 
by the formation of geosynclines. The effect of the folding 
will be to pile up the sedimentary rocks that have been 
formed from sediments deposited in the geosynclines, caus- 
ing them to form thicker layers. These thicker layers of 
lighter rock will tend, even after gravitational adjustments 
have taken place, to stand higher above sea level. The effect 
of one displacement in this respect would be slight, but the 
accumulation of the effects of many displacements through 
millions of years could lead to extremely important changes 
in the distribution of land and sea areas. Numerous displace- 
ments of the earth's crust could, in fact, constitute an essen- 
tial, and perhaps even the basic, mechanism for the growth 
of continents. 

Equally important for the general question of sea levels 
are the effects to be expected from a displacement of a sector 
of the crust toward the equator. Here the crust will be sub- 
jected to tension, or stretching. We have already noted that 
in this process innumerable fractures will be created in the 



THE MOUNTAINS 12$ 

crust, and these will tend to be filled up with magma from 
below. Since this magma, invading the crust, will average 
higher specific density than the rocks of the crust, it may in- 
crease the general weight of the crust, and thus depress it, 
causing a deepening of the sea. This would not occur if the 
separated blocks simply sank in the underlying magma until 
they displaced their own weight, in the manner suggested by 
Campbell. In that case, the crust would weigh no more than 
before. It seems, however, that volcanic activity is accom- 
plished by very complex chemical processes, and by the ab- 
sorption of vast quantities of lighter rock and its transforma- 
tion chemically into heavier rocks, to the accompaniment 
of much throwing off of gases into the atmosphere. It is also 
true, as we have noted, that massive lava flows may occur on 
the sea bottoms (or even, perhaps, within the crust, at points 
below the sea bottoms) as a result of displacement of the 
crust. These could have the effect of weighting the crust. 
Moreover, an equatorward displacement of an area must 
result in a gravitational effect opposite to that of the pole- 
ward displacement mentioned by Gutenberg. In this case, 
the crust must rise to achieve gravitational balance. In so 
doing it may have to draw into itself a considerable amount 
of the heavier rock underlying the crust. This obviously 
would tend to weight the crust. 

The foregoing factors, added together, may account for 
the observed deepening of the oceans, and the increase of 
their total surface area, from the poles to the equator. A 
careful survey indicates that this deepening is on the order 
of one kilometer or, perhaps, 4,000 feet (233). 

There is still another factor that may affect sea levels, 
but in an unpredictable way. It seems clear, for several rea- 
sons, that a displacement of the earth's whole crust must 
result in considerable readjustments and redistribution of 
materials of different densities on the underside of the crust. 
While these can hardly be predicted, they must affect the 
elevation of points at the earth's surface. 

Geologists believe that the underside of the crust has un- 



124 EARTH'S SHIFTING CRUST 

evennesses, corresponding to those at the surface, and that 
the crust varies considerably in thickness from place to place. 
They think, for example, that the crust is thicker under the 
continental surfaces, and thinner under the oceans, and that 
it is thickest of all under mountain ranges and high plateaus. 
Continents and mountain ranges not only stick up higher 
but they also stick down deeper. That is because they are 
composed, as an average, of lighter rock. The analogy is to 
an iceberg. An iceberg floats with one tenth of its mass above 
sea level, and nine tenths of it submerged. It is lighter than 
water per unit volume, and floats in the water displacing its 
own weight, and leaving its own excess volume above the 
surface. Continents and mountain chains, composed on 
the average of lighter rock, stand in the same sort of hydro- 
static, gravitational balance, and their downward projections 
are thought to be much greater than their upward, visible 
projections. The downward projections of mountain chains 
are called "mountain roots." 

The underside of the crust, then, has a sort of negative 
geography. The features of the upper surface are repeated in 
reverse on the undersurface, although, naturally, the details 
are missing. The effects are rather smoothed out. We should 
expect that the Rocky Mountains would make a sizable 
bump on the underside of the crust, but we couldn't expect 
to find any small, sharp bump just under Pikes Peak. The 
tensile strength of the crust, though limited, is sufficient to 
smooth out the minor features. 

As we attempt to envisage the situation at the bottom of 
the crust, we must remember that the rocks are subjected to 
increasing pressure with depth, and probably to increasing 
heat, and as a consequence they must tend to lose their rigid- 
ity and strength. We don't just come suddenly to the bound- 
ary of the crust at a given depth. On the contrary, the crust 
just fades away. The rocks of the lowest part of the crust 
must be very weak indeed, so that a very slight lateral pres- 
sure may suffice to displace them. 



THE MOUNTAINS 125 

It follows that when lateral pressures develop during a 
displacement of the crust, as the downward projections of 
continents and mountains are brought to bear against the up- 
ward extension of the viscous layer below the ocean base- 
ments, large blobs of this soft rock of lesser density will be 
detached from the undersides of the continents, or mountain 
ranges, and will get shifted to other places. If, as a result of 
this shifting around, the average densities of vertical columns 
extending from the bottom to the top of the crust get 
changed, then there will eventually be corresponding changes 
of elevation at the surface. Some areas might, as a result, tend 
to rise, and others to sink. This could account, naturally, for 
changes of sea level, and for many topographical features 
such as basins and plateaus. 

To sum up the question of sea levels, it appears that the 
assumption of displacements of the crust (especially if they 
are considered to have been numerous) may help to explain 
them. It seems able to explain why glaciated areas (which 
we consider to have been areas displaced poleward) appear 
to have stood higher relatively to sea level, and why periods 
of warm climate in particular regions appear to have been 
associated with reduced elevation of the land, and transgres- 
sions of the sea. The theory seems to satisfy Umbgrove's 
conclusion that sea-level changes have resulted from some 
"world-embracing cause" (430:93). It accounts, too, for 
Bucher's suggestion that regressions of the sea have resulted 
from subcrustal expansion, and transgressions from sub- 
crustal contraction, for this, obviously, is only another way 
of looking at a displacement of the crust (58:479). (If an area 
is displaced poleward, the effect of subcrustal contraction is 
created; if it is displaced equatorward, the effect of subcrustal 
expansion occurs.) At the same time it provides an explana- 
tion for the rhythmic changes of sea levels through geological 
history that so mystified Grabau: 

This rhythmic succession and essential simultaneousness of the 
transgressions as well as the regressions in all the continents, indicates 



126 EARTH'S SHIFTING CRUST 

a periodic rise and fall of the sea-level, a slow pulsatory movement, 
due apparently to alternate swelling and contraction of the sea- 
bottom (183). 



jo. Some Light from Mars 

Some very significant facts emerge from recent studies of 
other members of the solar system, especially from the work 
of Dr. Harold Urey, The Planets: Their Origin and Develop- 
ment (438). This is the work in which the theory of accretion 
of planets is developed, in contradiction to the older theory 
of the cooling globe. Dr. Urey also discusses the present state of 
knowledge regarding the structure of the moon and Mars. 

It appears that there are mountains on the moon, but in 
Dr. Urey's opinion these have been created by collisions with 
minor celestial bodies. Where the colliding body hit the 
moon more or less head on, craters (the largest more than 100 
miles across) were formed. Planetesimals that merely grazed 
the moon's surface left long ridges and valleys. Where the 
heat created by the impacts caused extensive rock melting, 
vast lava floods apparently took place, which cooled off, in 
tens or hundreds of thousands of years. The absence of air 
and water has resulted in an absence of erosion on the moon's 
surface, so that the features created by the collisions have 
not been obliterated except in cases where the lava flows have 
swamped them. 

In the case of Mars, the story is different. Urey assumes 
that Mars was once like the moon, both in size and in surface 
features. The removal of these features, which no longer 
exist, he thinks must have been due to the work of atmos- 
phere and water. He gives reasons for believing that Mars 
did have more water at one time, but that it escaped from 
the planet by a process that is also going on, more slowly, on 
earth. He states: 

. . . The surface appears to be smooth, a condition most easily 
explained as due to the action of water during its early history and 
no mountain building since then (438:65). 



THE MOUNTAINS 127 

In another place he says: 

. . . Mars appears to have no high mountains, and it is difficult to 
understand this unless it had some initial water. (In order for it to 
remain without mountains no folded mountains must have been 
formed subsequently; but this is another subject.) The formation of 
Mars and its surface followed a course similar to that of the earth 



So we see that Mars and the earth appear to have followed 
similar courses of development. They are similar in chemical 
composition and in structure, and have similar atmospheres. 
There are, apparently, only two important points of differ- 
ence, other than size. Mars, unlike the earth, has very little 
water, so that its polar icecaps are thought to be no deeper 
than hoarfrost, and disappear entirely in summer; and Mars, 
unlike the earth, has no folded mountains. 

A thought-provoking fact: on Mars, no great icecaps- and 
no folded mountains, no volcanic phenomena, no fault 
mountains! Surely this is no coincidence. Surely, it is sugges- 
tive of the fact that these features on earth have been the 
consequence of displacements of the crust, and that these dis- 
placements have been owing to the agency of great polar ice- 
caps. It might seem, at first glance, that the absence of folded 
mountains on Mars might be explained by the absence of 
deep accumulations of sediments produced by the weather- 
ing of rocks under the action of water, and the accumulation 
of these sediments in geosynclines with subsequent folding, 
but we have seen that geologists do not claim to explain the 
original creation of the geosynclines, nor to identify the source 
of the compressive stress that brings about mountain folding. 



ii. Undisturbed Sections of the Crust 

It has been objected that over extensive areas there are rock 
formations that appear to have been little disturbed over 
very great periods of time. If the crust has been displaced 



128 EARTH'S SHIFTING CRUST 

as often as is required by this theory, why would not the crust 
be universally folded to a far greater extent than it is? 

I think this objection has been partly answered where I 
pointed out that in a single displacement of the crust the 
folding would be comparatively slight, and that it would be 
confined to a small part of the earth's entire surface. I have 
suggested that it would be greatest along the meridian of the 
crust's maximum displacement, but that at some point be- 
tween this meridian and the two areas suffering no displace- 
ment, the compressions would tend to fall below the elastic 
limit of the crustal rocks, so that the crust would simply bend 
elastically, and then return to its original, apparently undis- 
turbed position, in some subsequent movement. It may be 
added that most of the changes of elevation resulting from a 
displacement of the crust would tend to be epeirogenic that 
is, they would be broad uplifts or subsidences of large regions 
resulting from the tilting of great segments of the crust, 
rather than merely local deformations of the rock structures. 

Another point that may be urged in answer to this objec- 
tion is that, apparently, over considerable periods the poles 
have tended to be situated again and again in approximately 
the same areas, possibly owing to the configuration of the 
continents. This would result in leaving some areas far re- 
moved for long periods from the meridian of maximum dis- 
placement of the crust. 



12. The Chronology of Mountain Building 

Another objection that may be raised to this theory of 
mountain building is that there are supposed to have been 
only a few great mountain-making epochs in the world's his- 
tory of two or more billion years, and that these epochs have 
been separated by very long periods when mountains were 
eroded away, and no new ones made. I shall indicate two 
reasons for holding that this concept is an illusion. 
The first reason is that the record of the rocks is incom- 



THE MOUNTAINS 12Q 

plete. It has been estimated that if all the sedimentary beds 
of all geological periods were added together (that is, the en- 
tire amount of sediment that has been weathered out of the 
mountains and continents and accumulated to make sedi- 
mentary rocks since the beginning of geological time), the 
total thickness of sediment would be about eighty miles. At 
the present time, however, the average thickness of the sedi- 
mentary rocks of the upper part of the earth's crust is esti- 
mated to be no more than a mile and a half (333). What has 
happened to all the missing sediment? The answer is that it 
has been used over again. At the present time, all over the 
earth, the forces of the weather and the sea are busy wearing 
away or grinding up rock, and most of the rock they are 
destroying is sedimentary rock. Thus more than 95 per cent 
of all the sedimentary rocks formed since the beginning of 
the planet has been destroyed. As a result of this, geologists 
have been forced to piece together this geological record 
from widely separated beds. They find a part of the Silurian 
sediment in the United States, and another part in Africa, 
and so on. 

The enormous difficulty of piecing together the geological 
record from these discontinuous and scattered beds is ren- 
dered even greater by the fact that vast areas of what were 
once lands are now under the shallow epicontinental seas, 
and even under the deep sea (as we shall see in the next 
chapter). Let us remember, too, that even among the still- 
existing beds now to be found on the lands, only a tiny 
percentage are at or near the surface and thus available for 
study. And of these a large proportion are in such remote 
and geologically unexplored areas as Mexico, the Amazon, 
and Central Asia. And still, despite these enormous handi- 
caps, new periods of mountain formation are constantly be- 
ing discovered. Umbgrove remarks that a long list of them 
has been "gradually disclosed to us" (430:27). It seems to me 
that there is unjustifiable complacency in the assumption 
that the list of mountain-forming epochs is now complete. 



130 EARTH'S SHIFTING CRUST 

How can we reach a reasonable guess as to the number that 
remain undiscovered? 

The second reason for holding that the idea of rare moun- 
tain-building periods is quite illusory is perhaps even more 
persuasive. It seems that a remarkable error has vitiated the 
interpretation of the evidence regarding these alleged pe- 
riods. The error has been exposed by the development of 
nuclear methods of dating recent geological events, already 
referred to, and to be discussed more fully later. These have 
revealed an unexpectedly rapid rate of geological change. 
The error, I think, consists in interpreting the geological 
evidence on the assumption that conditions as revealed in a 
particular deposit in one area necessarily determine world- 
wide conditions. Thus, evidence of an ice age in a particular 
deposit in one place has been interpreted as meaning a period 
of lowered temperature for the whole world at that time. In 
the same way, mountain-building revolutions were assumed 
to affect all parts of the world at once. The idea that moun- 
tain building might go on on one continent while another 
went scot-free was not entertained. 

The contemporaneousness of these events in different parts 
of the world rested, as we shall see, upon a very vague idea of 
geological time. The techniques for dating the older geo- 
logical formations never did, and do not now, allow reliable 
conclusions regarding the contemporaneousness of moun- 
tain building on different continents any more than they 
permit such conclusions regarding climatic changes. Margins 
of error amounting to millions of years must always be al- 
lowed. Triassic folding in India need not be contemporary 
with Triassic folding in North America, because the Triassic 
Period is estimated to have lasted about 35,000,000 years! 
Calculations of the rates at which the weather wears away 
mountains have shown that mountain ranges may be worn 
away in much less time than that. 

Thus, we cannot place reliance on the accepted notions of 
the occurrence of mountain-building revolutions in time and 
space, but must hold that the process was, in all probability, 



THE MOUNTAINS 1J1 

much more continuous than has been supposed, but confined 
to smaller parts of the earth's surface at any one time. Further 
support for this view is provided by the geologist Stokes, who 
remarks, in connection with the history of the Rocky Moun- 
tains: 

Although the Rocky Mountain or Laramide Revolution is popu- 
larly supposed to have occurred at the transition from the Cretaceous 
to the Tertiary, it has become increasingly evident that mountain 
building was continuous from place to place from the late Jurassic or 
early Cretaceous and that deformation continued through the early 
Tertiary and Quaternary (405:819). 

In other words, mountain building went on continuously in 
North America from the Jurassic Period, about 100,000,000 
years ago, into the Pleistocene Epoch, which is considered to 
have come to an end 10,000 years ago! This is excellent evi- 
dence in support of the conclusion that, in all probability, 
none of the alleged mountain-building revolutions occurred 
in widely separated periods, with long, quiet periods in be- 
tween. 

Krumbein and Sloss point out that this view is, in fact, be- 
coming widely accepted by geologists. They remark that 
"Gilluly . . . recently examined the evidence for and against 
periodic diastrophic disturbances, and he showed that such 
disturbances are much more nearly continuous through time 
than is generally supposed," and they conclude: 

Added complexity arises as additional stratigraphic studies afford 
data which imply that tectonic activity is continuous through time. 
The classical concept that a geological period represents a long in- 
terval of quiescence closed by diastrophic disturbances is not fully 
supported by these newer data (258:343). 



V : CONTINENTS AND OCEAN BASINS 



i. The Central Problem 

None of the mysteries of the earth is more baffling than the 
question of the origin and history of the continents and ocean 
basins. One of the most useful applications of the theory of 
crust displacements will be its application here. 

As with the problems already considered, there are many 
theories that are in violent conflict. The conflict is broad and 
deep, and since it involves two or three branches of science, 
which have adopted antagonistic points of view, it may even 
be called a civil war in science. It is fought over one issue: 
whether the present continents and deep ocean basins have 
been permanent features of the earth's crust since the forma- 
tion of the planet, or whether they have not. 

It would take too long to review the history of this war, for 
it extends far back into the nineteenth century. Instead, it 
will suffice to outline the principal positions adopted by the 
antagonists. Before we do this, however, it is essential to 
emphasize that most contemporary geologists, knowing the 
mystery surrounding these principal features of the earth's 
surface, have refrained from making very positive statements. 
Professor Daly, for example, after admitting that the forma- 
tion of continents could not be accounted for under the 
theory of the solidification of the crust from an originally 
molten state, remarked that 

We are now face to face with a principal mystery of nature. Ac- 
tually, the earth's substance is differentiated into the form of conti- 
nent overlooking deep ocean basin. That obvious, infinitely important 
fact, dry land on a continental scale, has to find its place in any theory 
of the earth. The problem is as difficult as it is fundamental. . . . 



Daly goes on to say that all he is able to offer on the subject 
is a guess, but that any reasonable guess is better than simply 



CONTINENTS AND OCEAN BASINS 1J3 

avoiding the issue, which, he observes, is the course too often 
taken. 

Daly's own guess will not do for us, because it is based both 
on the theory of an originally molten globe and on the theory 
of drifting continents. He suggests that when the earth was 
entirely molten, the lighter rock, which now forms the gra- 
nitic foundations of the continents, was floating on top of 
the heavier rock, of basaltic composition, and crystallized 
first, making a thin layer over the planet's whole surface. 
Then, for some reason (not entirely clear) all this lighter 
rock slid toward one hemisphere and piled up, making a 
supercontinent. Later this supercontinent broke up and 
drifted apart, as suggested by Wegener. 

Jeffreys also refers to the difference between the aver- 
age chemical composition of the continents and that of the 
ocean floors. There is a difference in the densities of the two 
kinds of rock, and this is the reason why the continents stand 
high and the ocean beds are low. But what brought about 
this difference of composition is itself unexplained. It is, says 
Jeffreys, 

. . . closely connected with the great problem of the origin of the 
division of the earth's surface into continents and ocean basins, which 
has not yet received any convincing explanation (239:159). 

Professor Umbgrove also has admitted that the field is 
wide open to any reasonable speculation. He feels that he 
is confined to mere guessing, but justifies what he writes 
thus: 

. . . But why should we not enter [this field] if everyone who wants 
to join us in our geopoetic expedition into the unknown realm of the 
earth's early infancy is warned at the beginning that probably not a 
single step can be placed on solid ground? (430:241). 

In view of this state of affairs, I shall not apologize if, at 
times, in the course of this and the following chapter, I shall 
seem to the reader to be venturing beyond the point where 
speculation can be immediately checked by the facts. To a 
certain extent, my suggestions will be simply logical deduc- 



EARTH'S SHIFTING CRUST 

tions from the general theory of crust displacements, and 
may be incapable, at least at this stage, of direct proof. 



2. The Views of the Geophysicists 

In this civil war between the sciences, the first group I shall 
call upon to present their side of the case are the geophysi- 
cists. Now the geophysicists, by and large, have very definite 
views about the continents, even though they cannot explain 
their origin. Their consensus is that the continents have been 
permanent features of the earth's crust from the "beginning," 
and this involves an equal permanence for the ocean basins. 
Changes of sea level there have been: so much cannot be de- 
nied; but according to the geophysicists these can have been 
only relatively important. At times the continental shelves 
(the narrow strips along the coasts where the water is only a 
few hundred feet deep) have been laid bare, and at other 
times the oceans have invaded the low parts of the conti- 
nents, but such changes (while unexplained) have been 
slight; they have not affected the main masses of the conti- 
nents. The continents, then, are original features dating, in 
their present positions, from the unknown beginnings of the 
planet. 

Of course, geophysicists would never make such broad 
statements as these, unless they had what seemed to them 
sufficient evidence. Their argument is easily stated. They 
point to the differences in composition. The continental rock 
is less dense, on the average, than the rock under the oceans. 
The force of gravitation brings all sectors of the earth's crust 
into rough balance, and this means that the lighter parts will 
stick up higher, like pieces of wood or ice floating on water. 
The continental sectors of the crust are considered to be both 
lighter and thicker than the oceanic sectors. The greater 
thickness makes up for the less density, so that things bal- 
ance off. 

This principle of the gravitational balance of the crust is 



CONTINENTS AND OCEAN BASINS 135 

referred to as the principle of "isostasy." We shall see, later, 
that there are some serious difficulties with the general theory 
of isostasy, as a consequence of which it cannot be regarded 
as definitely established. Still, on the whole, there is much to 
be said for it. And so the geophysicists ask how can anything 
alter the major concentrations of lighter or heavier rock, 
which, according to the theory of isostasy, must determine 
the locations of continents and ocean basins? A continent 
could not be destroyed without getting rid of a large amount 
of lighter granitic and sedimentary rock, and a new conti- 
nent could not be raised up without producing a vast amount 
of new rock of that kind. Since these things are impossible, 
changing continents around is impossible, and the less said 
about it the better. 



3. The Views of the Biologists 

While the geophysicists were developing these ideas, based 
upon laboratory experiments and principles of physics, the 
biologists and paleontologists were busily engaged with an 
entirely different question, which led them to diametrically 
opposite conclusions. They were classifying and comparing 
plants and animals from all parts of the world, those living 
today and those that lived in ages past. They were soon con- 
fronted by the fact that in many cases the same species of 
plants and animals could be found on lands separated by 
whole oceans. How was this to be explained? It could not 
be maintained that all these forms of life snails, grasshop- 
pers, ferns, fresh-water fish, and elephants had all built 
rafts, like Kon~tiki, in which to cross the Pacific. Nor was it 
possible to explain the distribution of all sorts of species by 
means of ocean currents, migratory birds, or winds. Behring 
Strait would not do either, because the plants and animals 
of the warm climates could hardly be tempted to chance the 
rigors of the Arctic merely to reach America or to escape 
from it. 



136 EARTH'S SHIFTING CRUST 

As we have seen, when the paleontologists studied the life 
of the remote past they found the same thing. The distribu- 
tions of the fossil plants and animals did not seem to pay 
any attention to the present shapes or positions of the conti- 
nents. Therefore, not knowing what the geophysicists were 
up to or not caring the biologists and paleontologists de- 
cided between themselves that they were in need of some new 
continents, or rather, in need of some old, now nonexistent 
continents, or at least a large number of former land con- 
nections across the present oceans. And so they went right 
ahead, and invented them. 

Wegener, of course, managed to explain a mass of evidence 
by moving the continents (450:73-89). Since the refutation 
of his theory, the same evidence needs a new explanation. 
Dodson gave the evidence for a North Pacific land bridge 
(not Behring Strait) based on the distributions of 156 genera 
of plants (115:373). Gregory also produced evidence for a 
Pacific land bridge (191). DeRance and Feilden presented the 
evidence for a land connection between North America and 
Europe in the early Carboniferous (319:!!, 331-32). Cole- 
man, basing himself no doubt on paleontological evidence, 
remarked that "India has many times been connected with 
Africa" (87:262). 

Dodson reconstructed the history of the Isthmus of Pan- 
ama, as indicated by the distributions of fossil plants and 
animals. According to him, North and South America were 
connected in the Cretaceous and in the early Paleocene, but 
later in the Paleocene, Panama was completely submerged. 
During the following Eocene and Oligocene there were islands 
but no continuous land in the area. The islands were com- 
pletely submerged late in the Oligocene. Land connection 
between the continents was re-established in the Pliocene, 
that is, very lately (115:375-76). It must be emphasized that 
the explanation for all these land changes is missing. There 
is no basis in the geological evidence for the assumption that 
the isthmus was never more than just barely submerged. 
There is no reason to exclude the possibility that it was rather 



CONTINENTS AND OCEAN BASINS 137 

deeply submerged at times. Later I shall show that the prob- 
lem cannot be solved by any theory that the melting of ice- 
caps in "interglacial periods" periodically raised the water 
level. 

One writer, who is considered a very special authority on 
the climates of the past, Dr. C. E. P. Brooks, gave a list of 
continents that must have existed about 300,000,000 years 
ago, if the distribution of plants and animals at that time is 
to be explained. He even names them (52:247-51): 

a. Nearctis, a "primitive North American continent/' 

b. North Atlantis, including Greenland and western Eu- 
rope. 

c. Angaraland, occupying part of the present Siberia. 

d. Gondwanaland, a huge continent extending from South 
America to India via South Africa. 

He states, further, that the evidence shows that Nearctis 
and North Atlantis were connected by a land bridge at about 
Lat. 50 N., and that the first three continents were separated 
from Gondwanaland by a great ocean, the Tethys Sea, which 
extended from New Guinea to Central America. Another 
authority, Beno Gutenberg, writes: 

. . . Nearly all specialists on such problems conclude that during 
certain p re-Tertiary periods land connections existed across sections 
of the present Atlantic and Indian Oceans. . . . During certain geo- 
logical periods land life was able to roam from land to land; on the 
other hand, such former connections of continental areas prevented 
sea life from moving from one part of the Atlantic to another (194: 
208-09). 

Gutenberg thus bears witness to the fact that the sea lif< 
as well as the land life of the past supports the idea of im 
portant changes in the positions of land masses. 

We can see that the suggestions advanced are of two kinds: 
sunken continents, and changing land bridges between conti- 
nents. Land bridges, of course, are more easily explained 
than sunken continents. However, we shall see that, for a 
number of reasons, they will not suffice of themselves. There 



138 * EARTH'S SHIFTING CRUST 

is evidence that points insistently to the former existence o 
whole continents in what are now oceanic areas. Only re- 
cently, for example, Dr. Albert C. Smith, of the Smithsonian 
Institution, concluded, from a massive study of the plants of 
the islands of the Southwestern Pacific, that the islands must 
be merely the remnants of an ancient Melanesian continent 
that broke up about 10,000,000 or 20,000,000 years ago (397). 
We shall see that there is plenty of evidence, besides the evi- 
dence of fossils, to support his conclusion. 

From what has been said about mountain formation, I 
think it is clear that the matter of the appearance and disap- 
pearance of land bridges is accounted for at the same time that 
the mountain ranges are accounted for. A displacement of 
the crust will lead to the uplift of long, narrow, folded tracts 
on the sea bottom as well as on land. One of these, coming 
into existence on the bottom of a shallow sea between two 
major land masses, could connect such land masses and con- 
stitute a land bridge. Its subsidence in a later movement of 
the crust could separate the land masses, and the subsidence 
could be partial, leaving islands, or total. 

It is interesting to see that Umbgrove found himself com- 
pelled, because of a mass of geological evidence, to support 
a theory of rapidly appearing and disappearing land bridges, 
which was advanced by Willis and Nolke, though he ad- 
mitted that * 'Their origin and submersion will probably re- 
main a mystery for some time to come. . . ." (430:238). 

Land bridges have been very convenient for many sci- 
entists seeking to avoid the horrid alternative of former 
continents. According to the picture drawn by some writers, 
these bridges were long snakelike arms, wriggling out this 
way and that, which just happened to make the right connec- 
tions between the right continents at the right times for the 
convenience of the right plants and animals. Often when the 
threat of a former continent loomed so imminently that its 
avoidance seemed hopeless, a land bridge would save the day. 
Most paleontologists were satisfied with land bridges, and did 
not insist on sunken continents, but some could not help 



CONTINENTS AND OCEAN BASINS 13 

feeling that there was something artificial about the idea 
they therefore continued to speculate about former conti 
nents. 

Should you ask, How did all this activity on the part o 
the biologists and paleontologists strike the geophysicists 
I can answer that it did not strike them at all. This can b< 
explained partly by the fact that geophysicists generally d< 
not read books on paleontology, and vice versa. So far as tin 
geophysicists were concerned, the speculations of the paleon 
tologists could be discounted as the insubstantial imagining 
of persons unacquainted with geophysics. To study the bio 
logical literature allegedly supporting these speculations was 
of course, not the function of geophysicists. It was outsid< 
their field, and, moreover, beyond their competence. Th< 
connection between these sciences was a distant one. The re 
lations between them were cool, to say the least. 



4. Geologists Allied with Biologists 

It would have been a sad thing for the biologists and paleon 
tologists had they not been able to find allies in the sever< 
struggle in which they were engaged (without, for the mos 
part, being aware of it). But find allies they did. For it soor 
developed that the geologists would not be content with th< 
limitations on continental change imposed by the geophysi 
cists. They could not be satisfied with land bridges. Fron 
purely geological studies of the stratified rocks of many land 
throughout the world came quantities of evidence insistently 
suggesting that the continents and ocean basins could no 
have had the permanence demanded by existing concepts ir 
geophysics. 

To begin with, there is an extraordinary contradiction ir 
the very fact that, while continents are supposed to have beer 
permanent, nearly all the sedimentary beds that compos< 
them were laid down under the sea. There is no denying thi 



140 EARTH'S SHIFTING CRUST 

fact. According to Schuchert, North America has been sub- 
merged no less than seventeen times (gGgaiGoi). According 
to Humphreys, the sea has covered as much as 4,000,000 
square miles of North America at one time (231:613). 
Termier argued that the sedimentary beds composing the 
mountain ranges extending eastward from the Alps to Cen- 
tral Asia, which were laid down under the sea, would have 
required that the ancient Tethys Sea, in which they were laid 
down, should have been about 6,000 kilometers (or perhaps 
4,000 miles) across (419:221-22). 

Geophysicists tend to argue that such seas, which clearly 
did exist, were merely shallow affairs, invasions of the conti- 
nents by the ocean owing to some unknown cause. The posi- 
tive evidence for this, based on the apparent absence from 
the sedimentary rocks of sediments formed in the very deep 
sea, has a fallacy in it, as will be made plain later. The posi- 
tive evidence against the assumption that all these seas were 
shallow seas is, on the other hand, enormously strong. Umb- 
grove, for example, remarks: 

. . . Not only have parts of the continents foundered below sea- 
level since pre-Cambrian times but they have even done so until quite 
recently, and their subsidence occasionally attained great depths! The 
present continents are but fragments of one-time larger blocks. . . . 
(430- 3)- 

A particularly important example of such foundering 
seems to have occurred in the North Atlantic, off the north- 
eastern coast of the United States. It has been found that the 
sediments that compose the northeastern states were derived 
in ages past from a land mass to the eastward in the present 
North Atlantic. This could have been Brooks's continent of 
North Atlantis. 

Some geologists, cowed by the geophysicists, have at- 
tempted to argue that these sediments might have been de- 
rived from a land mass situated on the present continental 
shelf, but the argument fails from every point of view. Brew- 
ster, for example, comments: 



CONTINENTS AND OCEAN BASINS 141 

It must have been a large continent, for the sand and gravel and 
mud which the rivers washed out to sea and the waves ground up on 
the shore have built up most of half a dozen big states, while in some 
places the deposits are a mile thick (45:134-35). 

Umbgrove says that while it is impossible to estimate the 
size of the land mass (called "Appalachia" by the geologists), 
it was clearly large, to judge from the fact that it has been 
possible to trace out in the sedimentary beds of the Appa- 
lachian Mountains the outline of an enormous delta formed 
by a giant river flowing out of the land mass to the east 

(430:35-38). 

Now the continental shelf of North America ends abruptly 
a very short distance from the coast. It is an extremely narrow 
strip between the coast and the so-called "continental slope," 
where the rock formations dip down suddenly and steeply 
into the deep sea. Its average width is only 42 miles, and its 
maximum width does not exceed 100 miles (46). If the sedi- 
ments had been derived from a land mass on this continental 
shelf, this very narrow land mass would have had to carry 
huge and repeatedly uplifted mountain ranges. Further- 
more, since drainage would naturally have carried sediments 
down both slopes of these mountain ranges, a large propor- 
tion of the material would have been carried eastward and 
deposited in what is now the deep ocean; but there is no evi- 
dence of this. 

The suggestion that the enormous volume of sediments 
forming the northeastern states of the United States came 
from the continental shelf must be considered improbable. On 
the other hand, it is plain that the former continent in the 
North Atlantic could not have been eroded away by rivers 
any farther down than approximately sea level. Erosion did 
not dispose of the continent, nor create the deep-sea basin. 
After erosion had finished its work, the continent itself sank 
to a great depth. Umbgrove has cited recent oceanographic 
research by Professor Ewing of Columbia, showing that this 
ancient land mass of Appalachia now lies subsided about two 
miles below the continental shelf (430:35-38). 



142 EARTH'S SHIFTING CRUST 

This extraordinary case is by no means unique, for Umb- 
grove has pointed out that the sediments composing much 
of Spitsbergen and Scotland come from the ocean west of 
them, while those composing the west coast of Africa come 
from a former land mass in the present South Atlantic. Most 
interesting of all, he indicates that the deepest of the world's 
deep-sea troughs (east of the Philippines), about seven miles 
deep, gives evidence that it was once part of a very large con- 
tinent (430:38). 

The evidence produced by Coleman, showing that a conti- 
nental ice sheet once invaded Africa from the sea, and that 
the Indian ice sheet must have extended on land far to the 
south of the present tip of India, is to the same effect. It 
serves to answer conclusively the argument about continental 
shelves. You can put just so much on a shelf. 

According to Umbgrove, there is ample evidence of re- 
peated upward and downward oscillations of the floor of the 
entire Pacific (430:236). In a kind of rhythm, the great ocean 
has become alternately shallower and deeper. In the absence 
of any explanation of this phenomenon, Umbgrove becomes 
geopoetic. There seems to him to be something almost mysti- 
cal in this slow pulsation of the living planet. He finds that 
the unexplained upward and downward movements are not 
limited to sea areas: 

... It should be noted that blocks that were first submerged, then 
elevated, and then once more submerged and elevated, are also met 
with on the continents. The sub-Oceanic features and the similar 
continental characteristics cannot be explained at present, for our 
knowledge of pre-Cambrian history and terrestrial dynamics is not 
yet extensive enough. . . . (430:241). 

Comparatively radical vertical changes in the positions of 
land masses are evidenced by a considerable number of an- 
cient beaches (some of them, however, not very old) which 
are now found at great elevations above sea level, and some- 
times far inland from the present coasts. Thus the geologist 
P. Negris claimed to have found evidences of beaches on 
three mountains of Greece: Mt. Hymettus, Mt. Parnassus, 



CONTINENTS AND OCEAN BASINS 143 

and Mt. Geraneia, at, respectively, 1,400 feet, 1,500 feet, 
and 1,700 feet above sea level. He found a beach on Mt. 
Delos at 500 feet (3243:616-17). William H. Hobbs cited 
a particularly interesting case of a beach of recent date now 
1,500 feet above sea level, in California: 

Upon the coast of Southern California may be found all the fea- 
tures of wave-cut shores now in perfect preservation, and in some 
cases as much as fifteen hundred feet above the level of the sea. 
These features are monuments to the grandest of earthquake dis- 
turbances which in recent times have visited the region (216:249). 

It would be possible to multiply endlessly the evidence of the 
raised beaches, which are found in every part of the world. 
Many of them may imply changes in the elevations of the sea 
bottoms, such as are suggested by Umbgrove. 

One of the most remarkable features of the earth's surface 
is the Great Rift Valley of Africa. The late Dr. Hans Cloos 
pointed out that the high escarpment along one side of this 
valley was once, quite evidently, the very edge of the African 
continent: not just the beginning of the continental shelf, 
but the very edge of the continental mass. In some vast move- 
ment that side of the continent was tremendously uplifted, 
and the sea bottom was uplifted with it as much as a mile, 
and became dry land. This is so interesting a matter, and of 
such special importance for our theory, that I quote Dr. 
Cloos at length: 

There are two rims to the African continent. Twice the funda- 
mental problem arises: why do the continents of the earth end so 
abruptly and plunge so steeply into the deep sea? . . . Even more 
astounding, what is the meaning of the high, raised and thickened 
mountain margins that most continents have? (85:68). 

. , . The short cross-section through the long Lebombo Chain 
looks unpretentious, but it illuminates events far from this remote 
plot of the earth. For here the old margin of the continent is ex- 
posed. Not so long ago, during the Cretaceous Period, the sea ex- 
tended to here from the east. The flatland between the Lebombo hills 
and the present coast is uplifted sea-bottom. . . . What we see are 
the flanks of a downward bend of High Africa toward the Indian 
Ocean. . . . 



144 EARTH'S SHIFTING CRUST 

But we see much more: the sedimentary strata are followed by 
volcanic rocks to the east of the hills. Some parallel the strata like 
flows or sheets, poured over them and tilted with them. Others break 
across the sandstone layers and rise steeply from below. This means 
that as the continent's rim was bent downward at the Lebombo hills, 
the crust burst, and cracks opened through which hot melt shot up- 
ward and boiled over. 

So the eastern margin of Africa at the turn of the Paleozoic Period 
was a giant hinge on which the crust bent down, to be covered by 
the ocean. What we see here is merely a cross-section . . . one can 
go further north or south, and even to the other side of the continent 
and discover that great stretches of this unique land have suffered 
the same fate. The oceans sank adjacent to the continents, and the 
continent rose out of the ocean (85:73-74). 

Cloos makes it clear that in one geological period the 
continent was bent down so that a part of it became sea bot- 
tom (not merely continental shelf) and that at a later period 
it was uplifted some 6,000 feet, the sea bottom became land, 
and the continental margin was shoved far to the east. When 
we contemplate gigantic movements of this sort, it seems 
reasonable to take the geophysical objections to changes in 
the positions of the continents with a grain of salt. If a large 
part of a continent can be shown not to have been perma- 
nent, it is unnecessary to assume the permanence of any of it. 
On the other hand, such changes need to be explained, and 
they need to be reconciled with basic principles of physics. 
The fact that theories of continent formation and history 
hitherto proposed have failed to solve the problem reduced a 
recent writer on lost continents to the following confession of 
ignorance: 

Since somebody can bring good, solid objections on one ground or 
another against all these hypotheses, however, we had better agree 
that nobody knows why continents or parts of continents sink, and let 
it go at that. No doubt a sound explanation, perhaps combining fea- 
tures of the older theories, will be forthcoming some day (64:161). 

It may be useful to consider, in juxtaposition, the African 
Rift with the question of the North Atlantic land mass al- 
ready discussed. In a sense, the two are complementary. In 



CONTINENTS AND OCEAN BASINS 145 

one case a continent apparently subsided; in the other it first 
subsided and then was raised up. Quite obviously the move- 
ments in both directions must have been related to one 
fundamental dynamic process. The physical geology of the 
Rift, which can be directly examined, shows that the indirect 
evidence of the sedimentary rocks of the northeastern states 
of the United States, and of Scotland and Spitsbergen (and 
the paleontological evidence), must be taken seriously. The 
evidence in favor of an important land mass in the present 
North Atlantic cannot be dismissed. 



5. The Evidence of Oceanography 

A great deal of new evidence bearing on the question of the 
permanence of continents and ocean basins has resulted from 
the oceanographic research of recent years. There has been a 
revolution in our ideas of the nature of the ocean floor. 
Formerly, it was thought that the ocean floors were continu- 
ous, flat marine plains, buried thousands of feet deep under 
an accumulation of sediments extending back in unbroken 
series to the earliest geological periods. After all, the theory 
of permanence of the ocean basins required this concept. It 
has been found, however, that, on the contrary, there are 
hills, valleys, mountain systems, and canyons on the sea bot- 
tom very much like those on land. There is no continuous 
thick layer of sediments. The features of the ocean bottom 
appear to resemble, in singular fashion, those of the land. 
One of our leading geologists, Richard Foster Flint, has 
written: 

Sound-wave surveying . . . has revolutionized our picture of the 
ocean floor. Instead of the plainslike surfaces that were once believed 
to be nearly universal, broad areas of the floor are now known to have 
an intricacy of detail that rivals that of complex land surfaces. In 
some places the detail seems to have resulted from local warping and 
faulting of the crust and submarine volcanic activity, but in others it 
consists of valley systems somewhat like those that diversify the land. 



146 EARTH'S SHIFTING CRUST 

Geologists are not agreed as to whether these features are valley 
systems cut by streams and later submerged or depressions excavated 
by currents beneath the sea (155). 

Now this problem must be examined as a whole. Certain 
facts are now obvious and can be plainly stated. 

In the first place, if a continent can be lifted up a mile, 
and the sea floor exposed, as in the case of Africa, surely it 
can also be let down. Thus there is no reason for anyone to 
lose his temper at the idea that some of these drowned sur- 
faces were once above sea level. On the other hand, it is not 
necessary to claim that they were in all instances eroded 
above sea level. We saw, in the last chapter, that the basic 
processes of mountain formation, folding, faulting, and vol- 
canism, are of a kind that can take place just as well below 
as above sea level. The only factor in mountain formation 
that is mainly operative on the land is erosion, and that is, 
as we have seen, a secondary factor. 

Secondly, one of the most impressive arguments in favor 
of the permanence of the ocean basins is that almost all the 
sedimentary rocks that compose the continents appear to be 
made of sediments that were laid down in comparatively 
shallow water, on or near the continental shelves. We have 
already seen, however, that parts of continents (at least) have 
been submerged to great depths, and that parts of the deep- 
sea bottom have been uplifted to form land. Why, then, have 
rocks composed of typical deep-sea sediments not been found? 

A number of factors may account for this. The primary 
factor may be the rate of sedimentation. In the deep sea this 
is extraordinarily slow as low as one inch in 2,500 years. 
Near the coasts it can be hundreds of times more rapid. 

The theory presented in this book provides a mechanism 
that would tend to operate against the consolidation of this 
deep-sea sediment into rock. Frequent displacements of the 
crust of the earth would naturally be accompanied by in- 
creased turbulence on the ocean bottom, by which sediments 
would be dispersed and mixed with other sediments. There 
has been in recent years a great extension of our knowledge 



CONTINENTS AND OCEAN BASINS 147 

regarding the operation of turbidity currents (137, 139, 141) 
caused by the slumping of sediments from the continental 
slopes, and by other forces. It seems that such currents, even 
now, are powerful enough to bring about considerable re- 
arrangement of the unconsolidated sediments of the ocean 
bottom. A displacement of the crust would greatly magnify 
their force, for it would cause extensive changes in the direc- 
tions of major ocean currents, changes in sea and land levels, 
extensive volcanism in the sea as well as on land, and an 
increased number and a greater intensity of earthquakes, 
which would occasion extensive slumpings of sediments along 
the continental slopes. If we consider that one such displace- 
ment would, in all probability, keep the turbulence at a high 
point for several thousand years, we can conclude that the 
resulting dispersal of deep-sea sediments would probably be 
on a considerable scale. 

Finally, since we cannot suppose that any area would be 
uplifted rapidly from the deep sea to the surface (that is, all 
the way in the course of a single displacement), it follows that 
in most cases deep-sea sediments would be raised into shallow 
water, where they would be exposed for a long time in an 
unconsolidated state to the erosive action of the much more 
rapid currents near the surface before they would be likely 
to be raised above sea level. A very small proportion of deep- 
sea sediment would then be mixed by the currents with a 
large proportion of sediment typical of shallow seas, and 
would, in most cases, entirely disappear. These factors to- 
gether dispose of this argument for the permanence of ocean 
basins. 

Another interesting line of evidence with respect to this 
problem is provided by the recent discovery on the bottoms 
of the oceans, already mentioned, of several hundred moun- 
tains of varying heights, which have been given the name of 
"sea mounts." These have the common characteristic of be- 
ing flat-topped. Apparently, their tops were made flat by the 
action of the sea at the time they were at the sea level. Now 



148 EARTH'S SHIFTING CRUST 

the flat tops are submerged anywhere from a few hundred 
feet to three miles below sea level. 

When these sea mounts were first discovered, they were 
explained in accordance with the theory of the permanence 
of ocean basins (210). It was proposed that as the sediments 
gathered in enormous thickness on the ocean floor through 
hundreds of millions of years, the floor actually gave way, 
and sank, taking the sea mounts down below sea level. This 
theory was undermined, of course, by the discovery that no 
such thick layer of sediments exists on the ocean floors, but 
that, on the contrary, the layer of sediments is in some places 
extremely thin, or even virtually nonexistent. 

Another line of evidence helps to dispose completely of 
this explanation of sea mounts. Foraminifera are minute pro- 
tozoa that live in the sea. Their species vary with differences 
in the depth and temperature of the water in which they live, 
and those of past geological periods, found in fossil state, 
differ from living species. Studies of fossilized foraminifera 
from the tops of the sea mounts have revealed that they are 
much younger than the sea mounts have been assumed to 
be (197). Comparatively recent species have been gathered 
from the tops of sea mounts subsided to great depths. Unless 
turbidity currents could suffice to carry such deposits long 
distances across the ocean floor and then upwards to the tops 
of the sea mounts, another cause for the subsidence of the 
sea mounts must be found. When we remember that Umb- 
grove referred to frequent upward and downward oscillations 
of the floor of the Pacific, resulting from an unknown cause, 
we can see that the idea of a gradual and continuous sub- 
sidence of the ocean floor under the weight of accumulating 
sediments is a singularly weak one, for even if the supposed 
layer of sediments existed, the theory still unaccountably 
ignores the recurring uplifts of the sea bottom. 

The foregoing considerations reveal the essential weakness 
of the conclusion that the seas that periodically invaded the 
continents were always shallow seas "epicontinental" seas, 
flooding the permanent continents. First there was land; 



CONTINENTS AND OCEAN BASINS 149 

then, no doubt, shallow seas; after that, in some cases, very 
deep sea, then again shallow sea, and finally again land, all in 
the same place. But the interludes of deep sea may have been, 
in many cases, very short, and the sedimentation resulting 
may have never been consolidated. Thus the deep sea could 
come and go, and nobody the wiser. New evidence bearing 
on this problem is now available as the result of recent Soviet 
oceanographic work in the Arctic. Soviet scientists have 
found evidence that the Arctic Ocean itself has existed only 
since the comparatively recent Mesozoic Era (364:18). We 
shall return to this evidence. 

It seems reasonable to conclude that at least some of the 
problems presented by the continents and ocean basins are 
soluble in terms of the principles described in this and previ- 
ous chapters. Land links may be explained as the conse- 
quences of mountain formation on the sea bottom; tempo- 
rary and limited uplift or subsidence of large areas may result 
directly from their poleward or equatorward displacement. 
The major changes, howeverthe enormous elevations and 
subsidences, the destruction and creation of continentsre- 
quire us to examine the deepest possible consequences and 
implications of crust displacement. We must now undertake 
this deeper examination. This requires us to take another 
glance at the nature and structure of the crust of the earth, 
to its full depth, as far as our present geophysical knowledge 
permits. 



6. The Deeper Structure of the Earth's Crust 

It has, until lately, been the impression that the earth's crust, 
considered as a crystalline layer between 20 and 40 miles 
thick, was itself composed of various layers, with rocks of 
increasing density at increasing depths. This would have 
been a natural development with a cooling earth, for it might 
be supposed that the lighter materials in a liquid would tend 
to float on the heavier ones, and would solidify in the order 



150 EARTH'S SHIFTING CRUST 

of their density, with the lightest on top. Daly, in 1940, pro- 
posed the following layering of the crust, at least under the 
continents: 

a. The sedimentary rocks, at the surface. 

b. Below these a layer of basement rocks of granitic type, 
ending about 15 kilometers, or 9 miles, down. 

c. A third layer of rock, of somewhat greater weight, about 
25 kilometers, or 15 miles, thick. 

d. A fourth layer, about 10 kilometers, or 6 miles, thick, of 
still heavier rock. 

Having proposed these layers, however, he added that "the 
exact depths of the discontinuities are not easily demon- 
strated" and "it seems clear that each of the breaks varies in 
its depth below the rocky surface" (97:17). In another place 
he gave evidence of light matter at the very bottom of the 
crust (97:223). These layers, then, according to Daly, are very 
peculiar. There is nothing regular about them. On the one 
hand, he gives rough estimates of their thicknesses. On the 
other hand, he indicates that these estimates are of little 
value. They are, in fact, mere rough averages; they indicate 
a trend toward increasing density with depth, together with 
enormous confusion in the distribution of materials. 

In view of the extreme uncertainties of Daly's view of the 
structure of the earth's crust, it can hardly come as a com- 
plete surprise that the most recent geophysical investigation 
of the structure of the crust by the method of sound-wave 
surveying has failed to show any distinct layering of the 
crust. The geophysicists Tatel and Tuve have reported that 
the results of the most recent studies, using the most recent 
techniques, indicate that rocks of greater or less density are 
intermixed in utter confusion, that the essential structure 
of the crust is really that of a rubble, on a large scale (416: 
107). 

The main argument of the geophysicists who speak in 
favor of the permanence of the continents, and, consequently, 
of the ocean basins, is based on the observed difference in 



CONTINENTS AND OCEAN BASINS 15! 

composition of continents and of the crust under the 
oceans, a difference that has been verified for the uppermost 
few miles of the continental and oceanic sectors of the crust, 
but not for the greater depths. 

Now, if everything below, say, a depth of ten miles were 
layered everywhere at equal depths with rock of equal 
densities, no quarrel whatever could be had with the geo- 
physicists who argue for the permanence of continents and 
ocean basins. For in that case, only a massive change in the 
distribution of the superficial layers of light and heavy rock 
could change the distribution of continents and ocean basins. 
Granitic or sedimentary rocks at the surface .would have to 
be destroyed or created in enormous quantity to destroy or 
create a continent. 

It is entirely otherwise with the structure as suggested by 
Daly and as revealed in the recent geophysical surveys. To 
understand this it is necessary only to visualize that the rela- 
tive elevation of the surface at any point is determined by 
the average density of the entire column of matter between 
the surface at that point and the bottom of the crust, where, 
presumably, the inequalities at different points are pretty 
well averaged out. 

If the crust is not definitely layered, if, as both Daly and 
recent geophysicists agree, there are radical variations in the 
structure, then the vital changes may occur at any depth, 
deep down as well as at the surface. There is reason to be- 
lieve that massive changes may occur more easily deep down 
than at the surface. Thus, the crust might be weighted in its 
lower parts by an intrusion of a great mass of molten rock 
of high density from below, a very likely result of a displace- 
ment. In either case, whether the addition of the heavy mat- 
ter occurred near the surface or far below it, the result would 
equally have been a depression of the surface, with a con- 
sequent encroachment of the sea. Obviously, a repetition of 
such movements could subside a continent to a great depth, 
without altering the composition of the superficial forma- 
tions. 



152 EARTH'S SHIFTING CRUST 

On the other hand, a shifting of the masses of lighter rock, 
which might have formed the downward projections of con- 
tinents and mountain chains, as the result of a displacement, 
could lighten certain sectors of the crust and result in their 
uplift. 

That rocks of light weight are to be found at the very 
bottom of the crust (and even in the downward projections 
under continents and mountain chains that extend to greater 
depth) might, as a matter of fact, have been deduced from 
Daly's observation that the process of mountain folding has 
involved the whole depth of the crust, and not just its surface 
layers (97:399)- His suggestion is that since the folding of 
the crust to form mountain ranges involves its horizontal 
shortening, the horizontal shearing movement has to take 
place at the level where displacement will be easiest, which 
will be at the bottom of the crust where the rock has mini- 
mum, or zero, strength. For it is plain that at a level at which 
the rock possessed any considerable tensile strength, the 
shearing of one layer over another horizontally would be 
practically out of the question. 

It would seem, from these considerations, that the com- 
monly used terms "sial" and "sima" to differentiate lighter 
from heavier material in the crust, especially when they are 
presumed to indicate different layers, have very little mean- 
ing. They amount to trends merely, and take no account of 
the detailed distributions of the materials of different density 
either vertically or horizontally. It would be wrong, there- 
fore, to assume that just because we find a layer of basalt on 
the floor of the Atlantic (as has been recently reported) this 
layer necessarily extends to the bottom of the crust, and is 
not underlain, at greater depth, by sedimentary and granitic 
rocks of less density. It is even true that the layer of basalt 
may have been extruded during the subsidence of the sea 
bottom in the last movement of the crust, and have been, 
in itself, one cause of the subsidence. 

Jaggar, for one, considered that it was far more reasonable 
to account for subsidence or elevation at the surface by 



CONTINENTS AND OCEAN BASINS 153 

changes of weighting deep in the crust than by erosion and 
sedimentation at the surface. He remarked: 

... It would seem possible that intrusive and extrusive processes 
may lighten or weight the crust much more profoundly than the 
movement of sediments (235: 153). 

How, precisely, would these processes be apt to be set in 
motion by a displacement of the crust? We saw that a dis- 
placement would cause a general fracturing of the crust, the 
creation of a new world-wide fracture pattern. In areas moved 
toward the equator, the extension of the surface area would 
involve some pulling apart of the crust, the separation of the 
fragments, their subsidence into the semiliquid melt below, 
and the rise of the magma into the fractures, with, at some 
points no doubt, massive eruptions on the surface. Differen- 
tial movements of blocks of the crust would occur as each 
sought its gravitational equilibrium, some rising and others 
subsiding. In areas moved poleward compression would be 
the rule, with some folding of the crust, with block faulting 
accompanied by tilting of larger or smaller blocks. In these 
areas the strata of lighter rock would grow thicker, from 
being folded upon themselves; in equatorward-moving areas, 
on the other hand, they would tend to grow thinner, because 
much of the lighter rock might be engulfed in the rising 
heavy magma. 

However, major changes in the situation of continents 
require additional processes, even though changes such as 
those suggested above might, if they accumulated over long 
periods of time, produce very important results. The massive 
changes, capable of subsiding or elevating continents, might 
be of two different sorts, though both of them must, in the 
nature of things, remain speculative for the present. One of 
these would be the massive intrusion of immense quantities 
of heavy magma into the crust (resulting finally in plateau 
basalts). Such an effect could be produced by subcrustal cur- 
rents set in motion by a displacement, and would have the 
effect of causing a major subsidence at the surface. The other 
cause of massive change in the average density of a given col- 



154 



EARTH'S SHIFTING CRUST 




\ 



Fig. V. 



Consequences of Displacement: Cross Section of Earth at 96 
East of Greenwich Showing Centrifugal Effect of Icecap 



In Figs. V and VI the artist imaginatively suggests some consequences of 
a displacement of the crust. On this page we see a cross section of the 
earth before the movement, with the eccentric icecap above the equilib- 
rium surface of the earth. On page 155 we see a cross section of the earth 
after a displacement through about 30 degrees of latitude. The drawings 
are not to scale. It has been necessary, for purposes of illustration, to 
exaggerate the oblateness of the earth, the depths of the oceans, and 
the thickness of the crust several hundred times. The drawings illustrate: 
(i) The subsidence of the crust in areas displaced toward the equator, 
relatively to sea level, and its uplift in areas moved poleward. (2) The 



CONTINENTS AND OCEAN BASINS 



155 




Fig. VI. Consequences of Displacement: Cross Section of Earth at 96 
East of Greenwich Showing Hypothetical Effect of Shift of Crust 



fracturing and tilting of crustal blocks, suggested schematically. It should 
be understood that in reality the blocks would be comparatively small 
and the fractures would be numbered in millions. (3) The displacements 
of parts of the downward projections of the crust under continents and 
mountain chains, which would have an effect on the permanent eleva- 
tion of the surface relatively to sea level. (4) The volcanism attending 
the movement, with the projection into the atmosphere of volcanic dust 
capable of causing meteorological effects. 



156 EARTH'S SHIFTING CRUST 

umn of the crust (that is, a section extending from top to 
bottom of the crust) would be a shifting of light matter from 
one point to another under the bottom of the crust. This 
matter was discussed in the last chapter. While in that chap- 
ter relatively minor effects were considered, it is true, never- 
theless, that the shifting of light matter from one point un- 
der the crust to another could take place on a very large scale. 
What might be the upshot of all these changes during a 
displacement of the crust? The result might well be that 
while the distribution of light and heavy matter near the 
surface would be unchanged, its distribution (average den- 
sity) between the surface and the bottom of the crust would 
be materially changed. This is undoubtedly the direction in 
which we must look for a solution of the problem of con- 
tinents and ocean basins, as a means of reconciling geophysi- 
cal ideas with the evidence of biology and geology. 

I cannot close without reference to a singular confirmation 
of the line of reasoning adopted in this chapter, which I find 
in Umbgrove's discussion of the work of the geologist Barrell, 
with whom he disagreed. 

Umbgrove is considering the question of the submergence 
of continents. It is clear from his discussion that Barrell's 
conception of the process requires a theory of crust displace- 
ment. Umbgrove states the problem thus: If we are to sup- 
pose the submergence of continents, we must either suppose 
a change in the amount of the ocean water, which, if it in- 
creased, could flood a continent (or several at once), or, if the 
water remained about the same in quantity, the submergence 
of one continent must be balanced by the elevation of an- 
other. He presents the findings of specialists to show that 
the quantity of water on the earth's surface has remained 
about the same, from the earliest times, and adds: 

Should one, nevertheless, cling to the theory of submerged conti- 
nents, the only alternative would be to assume that while vast blocks 
were being submerged in one area, parts of the ocean floor of almost 
identical size were being elevated in others. . . . 



CONTINENTS AND OCEAN BASINS 157 

It is not quite clear, however, why such opposed movements should 
have occurred in areas of almost equal extent. Nor is it clear why 
these movements should have occurred in such a way that the sea- 
level remained comparatively stable. . . . (430:235-36). 

But a displacement of the crustor several displacements 
would fulfill all these requirements. In a displacement two 
quarters of the surface, opposite each other, must move to- 
ward the poles, while the other two quarters must move to- 
ward the equator. Whatever forces tend to produce uplift in 
the poleward-moving areas will be balanced by equal forces 
producing subsidence in the quarters moving equatorward. 
And the sea level would be stable, except for very minor 
fluctuations. 

Barrell himself suggests that subsidence of continental 
areas would be aided by liquid intrusions, "the weight of 
magmas of high specific gravity rising widely and in enor- 
mous volume from a deep core of greater density into these 
portions of an originally lighter crust. . . ." (430:235-36). 

Barrell's suggestion points to the chief weakness of the 
geophysical argument in favoi of the permanence of the con- 
tinents. As I have already pointed out, geophysicists seem, 
too often, to take as the frame of reference only the outer- 
most ten miles or so of the crust. Theoretically they base 
calculations on the full depth of the crust, but practically 
this assumption is cancelled out by the assumption that the 
crust is arranged in layers of equal density, so that significant 
changes of density in depth are excluded. But if the real 
possibilities of changes of average density in the full depth 
of the crust are taken into account, the difficulties in the 
face of the subsidence and elevation of continents vanish. 



VI : THE SHAPE OF THE EARTH 



In the two preceding chapters we have considered the evi- 
dence for displacements of the earth's crust provided by 
mountain chains, earth fractures, volcanic zones, continents, 
and ocean basins. We have had occasion to refer, a number 
of times, to the effects of the force of gravity, and of the 
earth's rotation, on the earth's crust. The understanding of 
the theory of crust displacement presented in this book de- 
pends entirely on a correct understanding of these two forces, 
and of the operation of what we call the principle of isostasy. 
The ideas are not difficult, provided certain essentials are 
kept in mind. 



j. Isostasy and the Icecap 

The globe we live on is shaped primarily by the force of 
gravitation. The weight of the materials of which it is com- 
posed is greater than their strength, and they have therefore 
been bent, broken, or forced to flow by this force until the 
globe has become a sphere. It is not, however, a perfect 
sphere. The earth deviates from being a perfect sphere be- 
cause it is rotating rapidly, and the rotation produces a cen- 
trifugal effect that tends to throw the materials outward at 
right angles to the earth's axis, and against the force of grav- 
ity. This slightly modifies the earth's shape, producing a 
bulge around the equator and a flattening at the poles. The 
earth modifies its shape until the two forces are in balance, 
and the resulting oblate sphere is called the "geoid." 

Of course, there is always a considerable amount of shift- 
ing of materials going on on the face of the earth, rivers 
bringing down sediment to the sea, icecaps growing and 
melting, and these changes are constantly upsetting the bal- 



THE SHAPE OF THE EARTH 159 

ance and requiring readjustments. The crust of the earth, 
being very thin as compared with the whole diameter of the 
globe, is correspondingly weak, and usually gives way if much 
material is accumulated on it at any one spot. The layer 
under the crust is considered to be quite weak, and it per- 
mits the crust to give way by flowing out from under. This 
process is called "isostatic adjustment/' Funk and Wagnalls 
define isostasy as follows: 

Theoretical condition of equilibrium which the earth's surface 
tends to assume under the action of terrestrial gravitation as affected 
by the transference of material from regions of denudation to those 
of deposition, and by difference of density of various portions of the 
earth's mass near the surface. 

In the last chapter we considered at length the effects of 
the differences of density of rocks under oceans and con- 
tinents, and how heavy rocks tend to reach equilibrium at 
lower elevation, and lighter rocks tend to be found in con- 
tinents and mountain chains. 

According to the principle of isostasy, it has been widely 
assumed that an icecap such as the one in Antarctica should 
be in good isostatic equilibrium. Of course, if this were true, 
the centrifugal effect of the icecap would be balanced at 
every point by the force of gravity, and there would be no 
effect left over to tend to shove the crust over the plastic 
layer below. There might be a slight effect resulting from 
the elevation of the continent and the icecap above the 
mean earth surface, but it would be too small to consider. 
Thus, our theory depends upon our ability to show that 
isostasy has not operated effectively in Antarctica. The ques- 
tion becomes one of estimating the difference between the 
rate of growth of the ice sheet, the rate of yield of the crust, 
and the rate of flow of the plastic layer under the crust. The 
calculation must also take account of the amount of load 
that may be borne by the crust, indefinitely, out of isostatic 
adjustment, because of its degree of tensile strength. Camp- 
bell's calculations of the centrifugal effect of the icecap, and 
of the resulting bursting stress on the crust (Chapter XI), 



160 EARTH'S SHIFTING CRUST 

are based on the assumption that the whole mass of the ice- 
cap is uncompensated. They are only approximations, and 
must be modified as soon as more information as to the de- 
gree of the isostatic adjustment of the icecap is available. 
On the other hand, it does not necessarily follow that the 
gravity measurements to be taken in Antarctica during the 
coming year will be able to provide a definite answer to 
the question. It is obvious that the theory of isostasy is at pres- 
ent under considerable attack, and that differences of opinion 
exist as to the validity of the various methods of interpreting 
the findings about the gravitational balance of the crust. 
Daly himself remarked that probably none of the present 
methods for determining the degree of isostatic adjustment 
of a crustal sector was capable of getting very close to the 
truth. A far more serious attack on the theory was made some 
time ago by Hubbert and Melton. They pointed out that 
all methods of reducing gravity data to measure isostatic 
compensation depend upon assumptions regarding the dis- 
tribution of materials in the earth, which must be regarded 
as essentially unknown (226:688). They conclude: 

The fields providing data on the subject of isostasy are geodesy 
[measurement of the shape of the earth], seismology [study of patterns 
of earthquake waves], and geology. The data of the first, which until 
recently have provided the main support of isostatic theory, have 
been shown by Hopfner to be invalid. The data of the second have 
only an indirect bearing on the question. The data of the last are 
more often than not contrary to isostatic expectations. Hence, the 
theory of isostasy must for the present be regarded as resting upon a 
none too secure foundation, and it is hardly trustworthy for use as a 
major premise in present discussions of earth problems (226:695). 

In the following pages I shall proceed on the assumption 
that the isostatic principle is generally correct, even though 
present methods of measurement are unsatisfactory. I shall 
assume that the materials of the earth's surface are under 
constant gravitational pressure to conform to the ellipsoidal 
shape of the earth, and that this applies to the icecap, and 
will bring about a tendency of the crust under the icecap 



THE SHAPE OF THE EARTH l6l 

to yield and sink, displacing soft rock from below as the ice- 
cap grows in weight. At the same time I should like to pre- 
sent a number of considerations indicating that there is, at 
the present time, a massive departure from isostatic equi- 
librium in Antarctica. 

One of the most astonishing things revealed by the new 
techniques of radioelement dating is, as we have seen, the 
rapid rate of the growth both of the present ice sheet in 
Antarctica and of the last great icecap in North America. 
Even before the new knowledge was available, however, 
various authorities had agreed that there must be a consid- 
erable lag between the growth of an ice sheet and the adjust- 
ment of the crust to it by subcrustal flow of the plastic rock 
out from under the glaciated tract. The geologist Wilhelm 
Ramsay, referring to this lag, said: 

... As the icecaps grew bigger and thicker, they loaded more 
and more the areas occupied by them. The crust of the earth gave 
way, and began to sink, but not in the proportion that the loads 
increased (352:246). 

Ramsay pointed out that the "rebound" of the crust follow- 
ing the removal of the ice still continues thousands of years 
after the end of the ice age, showing how slowly the crust 
adjusts. Daly also referred to this lag: 

Owing to the stiffness of the earth's materials and the sluggish- 
ness of their response to deforming forces, the basin [around the 
Baltic] persisted long after the ice melted away. The lower parts of 
Scandinavia and Finland were kept submerged under the sea. . . . 
(97^90). 

According to Daly, the present isostatic distortion in the 
center of the area once occupied by the great Scandinavian 
ice sheet is the equivalent of "a plate of granite with a 
thickness of 160 to 270 meters of rock" (97:386-87). This 
amounts to about three times as much ice. Thus it would 
amount to an ice sheet between 1,500 and 2,500 feet thick, 
and this in spite of the fact that isostatic adjustment has 
theoretically been proceeding in that area for perhaps 15,000 



i6s EARTH'S SHIFTING CRUST 

years. If we assume that the lag was the same during the 
growth of the icecap, we can see that there may have been 
an enormous excess of matter on the crust when the Scandi- 
navian icecap reached its apogee. 

In another way, Daly shows how slowly the compensating 
flow that permits adjustment takes place. He refers to the 
fact that erosion from a continent or large island appears to 
create negative anomalies (deficiencies of mass) on the land 
and positive anomalies in the sea (97:297-98). This is so 
because the crust does not adjust as rapidly as erosion takes 
place. Yet we can easily see that the accumulation of ice is 
faster than the weathering of rock and the deposition of 
sediments in the sea. 

The geophysicist Beno Gutenberg has made a number 
of statements that strongly support the same conclusion. In 
discussing the zone within the earth where adjustment is 
carried on, he says: 

... It is inferred that this depth represents (in geologically 
stable regions) the critical level below which strain is nearly reduced 
to zero by subcrustal flow in periods of, say, 100,000 years (194:316). 

The period of 100,000 years indicated by Gutenberg ap- 
pears to be a multiple of the time required for the growth of 
a vast continental icecap. In another place, he refers directly 
to the lag between the growth or retreat of an ice sheet and 
the adjustment of the crust. After listing other ways in which 
the isostatic balance of the crust may be disturbed, he adds: 

A probable instance ... is the lag in complete compensation 
of the load provided by the Pleistocene ice sheets. This is shown by 
the recoil of the tracts unloaded by the melting of the ice (194:319). 

He remarks, further: 

The processes by which isostasy is maintained must be extremely 
slow, and consequently, this equilibrium is liable to disturbance by 
geological events (194:318). 

Gutenberg and Richter, in their volume on The Sets- 
mici'y of the Earth, express the known facts about adjust- 



THE SHAPE OF THE EARTH 163 

ment within the rigid crust itself. They remark: ". . . it 
requires several thousand years for the strains due to the re- 
moval of the ice load to be reduced to half" (195:101). This 
and the preceding statements may serve to establish the rea- 
sonable presumption that any icecap, at the height of its 
rapid accumulation, must be largely uncompensated. 

But even if, during the rapid growth of the present An- 
tarctic icecap, a degree of isostatic adjustment has taken 
place, this does not end the matter for us. We must ask, 
Where does this plastic rock go? Presumably it flows out, 
under the crust below the ocean bed, beyond the fringes of 
the ice-covered continent, at a depth of twenty to forty miles 
below the surface of the earth. It may raise the crust some- 
what for a distance beyond the edges of the ice sheet. Dr. 
Harold Jeffreys gave it as his opinion that, if a gravity survey 
of Antarctica should be undertaken, we might expect to 
find marked positive anomalies around the coasts (241). But, 
since in general the plastic rock under the crust is not flowing 
into any area of deficient mass, the flow, upraising the coasts 
or the sea bottoms off the coasts, must still constitute excess 
matter, and must exert a centrifugal effect about equal to 
the former effect of the ice that has now been brought into 
equilibrium. 

Let us consider this point a little further. We have noted, 
above, that according to the definition of isostasy, the process 
is a response to the transfer of material from one region to 
another: sediment is removed from an area of "denudation" 
and transferred to an area of "deposition." The area of dep- 
osition, then, sinks under the load, and a flow of rock under 
the crust moves back to the area of denudation, compen- 
sating for the material that has been removed, and restoring 
the equilibrium. But where can the plastic rock displaced 
by the icecap flow? No adjacent area ha$ been lightened by 
the removal of sediment; the plastic rocK must, then, wher- 
ever it flows, create a distortion, a surplus of matter, which 
will have a centrifugal effect. 

From the standpoint of the theory presented in this book, 



164 EARTH'S SHIFTING CRUST 

it makes no difference whether the excess mass that creates 
the centrifugal effect is constituted of ice or whether it is in 
part constituted of rock. It may be concluded, therefore, that 
the isostatic process itself is ineffective in counteracting the 
centrifugal effects of icecaps. 

We may conclude, then, first that the rate at which isostasy 
may work is too slow to keep up with the deposition of the 
ice; and second, that in so far as it does work it will not elimi- 
nate the centrifugal effect of the uncompensated mass, but 
will merely substitute rock for ice. 



2. The Antarctic Icecap Is Growing 

The theory presented in this book requires, of course, that a 
polar icecap should grow, and continue to grow, though not 
perhaps steadily, until it is big enough to move the crust. In 
this connection it is important to examine certain current 
ideas about the Antarctic icecap. 

It is widely believed that the Antarctic icecap, like some 
ice fields in the Northern Hemisphere, is in recession, and 
was once greater than it is now. This is a mistaken impres- 
sion, the error of which can be easily shown, even without 
any more data from Antarctica. I will venture to remark, 
indeed, that any further data from that continent are likely 
to show that the icecap there is in a phase of rapid expansion. 

I will begin with the northern ice fields, about which more 
is known. There is no doubt that most of them are melting, 
but the exceptions are very significant. These include the 
Greenland icecap, which appears to be holding its own 
(after having considerably expanded since the Viking settle- 
ments there during the Middle Ages), and the Baffinland 
icecap, which is growing. The mountain glaciers of the Amer- 
ican northwest have, apparently, started a readvance (329). 
The most important fact regarding those northern ice fields 
that have been in retreat is that their retreat began only 
about the year 1850, and that, before that, they were expand- 



THE SHAPE OF THE EARTH 165 

ing generally for about 300 years. Between 1550 and 1850 
the old Viking settlements in Greenland were overwhelmed 
by the advancing ice. From this it follows that the present 
trend in the northern ice fields is not a long-term trend, but 
only an oscillation. Therefore, it must not be deduced that 
we are just getting out of a glacial period, and that all ice 
fields are retreating and will continue to retreat. 

Recent weather research has made it plain that alternating 
climatic phases of slightly colder or warmer temperatures 
have been the rule for some thousands of years. Such phases 
would have no connection with any movement of the earth's 
crust, but are probably related to varying atmospheric fac- 
tors, such as slight variations in the amount of volcanic dust 
in the air, or short-term sunspot cycles. It is known that the 
warmest phase of the climate, since the ice age, occurred 
between 6,000 and 4,000 years ago. This did have a connec- 
tion with the most recent displacement of the crust, as I will 
show later on. This warm period is in itself sufficient evi- 
dence that there has been no steady warming of the climate 
since the icecaps melted. 

It is even true that a slight warming of the climate, such 
as appears to have occurred since about 1850, may increase 
precipitation of snow on the Antarctic continent. This sug- 
gestion has been advanced by a number of meteorologists. It 
is based on the following reasoning: The Antarctic average 
temperature is much colder than that of the Arctic. A slight 
warming of world temperatures will increase the amount of 
the humidity in the atmosphere. In northern regions, the in- 
creased humidity in the world's atmosphere may result in 
increased rainfall, while in Antarctica, because of the lower 
temperature, the increased precipitation may mean increased 
snowfall. 

Up to the present time, only one impressive body of evi- 
dence has been produced to prove that the Antarctic icecap 
has receded from a former greater extent. This evidence con- 
sists of numerous indications of ice action on the barren 
sides of Antarctic mountains as much as 1,000 feet above the 



i66 EARTH'S SHIFTING CRUST 

present levels of the ice. As matters stood before the develop- 
ment of nuclear methods of precision dating, this evidence 
appeared conclusive. It certainly argued strongly that the 
icecap was greater in the past. 

We are now able to take a different view of the matter. 
Now we know that this icecap is largely of very recent growth. 
We know, too, that before a preceding temperate age in 
Antarctica there was another icecap, and that there were 
several icecaps during the comparatively short period of the 
Pleistocene alone. We can assume, moreover, that the ice 
centers of the different ice sheets were in different places, so 
that the distribution of the ice its thickness in different 
places would be different from now, even if the total amount 
of ice were about the same. (See Figure VII.) 

If the question is asked, Cannot we tell from the appear- 
ance of the striations, and other evidences of ice action on 
the Antarctic mountainsides, how long ago they were made?, 
the answer is No. The processes of weathering and erosion 
in Antarctica are slow. The striations, even if they were very 
old, could look as if they were made yesterday. Henry, in the 
White Continent, discussing the visit of Rear Admiral 
Cruzen in 1947 to a camp at Cape Evans that had been aban- 
doned by Scott more than thirty-five years before, throws 
some light on this peculiarity of Antarctica: 

. . . From the camp's appearance, the occupant might have left 
only within the past few days. Boards and rafters of the cabin looked 
as if they had just come from the saw mill; there was no rot on the 
timbers; not a speck of dust on the nailheads. A hitching rope used 
for Manchurian ponies looked new and proved as strong as ever 
when it was used to hitch the helicopter. Biscuits and canned meats 
still were edible, though they seemed to have lost a bit of their 
flavor. A sledge dog, which apparently had frozen to death while 
standing up, still stood there looking as if it were alive. A London 
magazine, published in Scott's day and exposed to the elements since 
his departure, might have been printed that morning (206:44). 

The same factors intense cold, with absence of the destruc- 
tive process of alternate melting and refreezing, and absence 



THE SHAPE OF THE EARTH 167 

of water action, and the absence of minute organisms would 
preserve indefinitely the freshness of the glacial evidences. 
If there are any who still hesitate to accept the evidence of 
several successive ice ages in Antarctica during the Pleisto- 
cene, let them remember that we recognize four in North 
America and in Europe during that period, and that even 
here it is not always easy to assign glacial evidences to the 
correct glaciation. 

Once it is fully recognized that the geological evidence of 
Antarctic ice recession must be reinterpreted, we are in a 
better position to evaluate the large mass of evidence now at 
hand regarding the present accumulation of snow in Antarc- 
tica. Geologists have hesitated, because of the earlier evi- 
dence, to interpret the data at all. Among the important 
items of information are the following: Henry mentions evi- 
dence of an accumulation of 18 feet of snow in seven years 
on the Antarctic barrier ice (206:75). The party that visited 
Antarctica on the icebreaker Atka in 1954 found evidence of 
the accumulation of 60 feet of snow at one spot since 1928: 

One of the Atka's three Bell helicopters took off with Commander 
Glen Jacobsen, the ship's captain, as observer. It landed at the 1928 
camp and found that one of the three towers was completely buried 
in snow although it had originally stood more than 70 feet high. The 
two others barely showed above the drifts (411). 

In 1934, when Byrd made his second trip to Antarctica, he 
found that the Ross Shelf ice had encroached 1 2 miles on the 
sea since Scott charted it in 1911 and that there was much 
more ice in the Bay of Whales than when Amundsen visited 
it in 1911-13. Recently, Bernhard Kalb wrote in the New 
York Times: 

. . . Little America II the 1933-35 base had been built directly 
on top of snow covered Little America I the 1928-30 base. But the 
last twenty years of snowfall had obliterated that base, too. The only 
reminders that there is a sort of Antarctic Troy entombed in the 
Ross Sea shelf a spectacular table of glacier-fed ice floating in the 
sea, three times the size of New York State were two steel radio 
towers and the tops of half a dozen wooden antenna poles. The towers, 



168 EARTH'S SHIFTING CRUST 

dating from 1929, had been seventy feet high; now less than ten 
feet of them could be seen (246:59-60). 

The best evidence for the rate of snow accumulation in 
Antarctica, however, comes from some scientific measure- 
ments taken in connection with "Operation Highjump" by 
the United States Navy, in the years 1947-48. The reports of 
this thorough study were included in the Army Observer's 
Report of the expedition, and were made available to me 
through the kindness of Admiral Byrd. Observations were 
made at a number of points; the snowfall was found to have 
averaged nine inches per year since the previous Byrd expedi- 
tion (12). 

Of course, snow does not accumulate equally at all points 
in Antarctica. In many exposed places it may not accumulate 
at all, but may be blown away by the wind. In the interior it 
is reasonable to suppose it may accumulate at a slower rate 
than on the coasts. Since measurements taken in a few areas 
only may be seriously misleading, we should briefly review 
the general factors controlling the snowfall and snow accu- 
mulation. 

First, let us cite the testimony of a scientist-explorer, Nor- 
denskjold, who was the first to take scientific measurements 
of the snowfall in Antarctica. He also took temperature rec- 
ords during many months. Of these he said: 

They also prove that there is a tremendous difference between 
an arctic and an antarctic summer climate, and that our summer 
was colder than winters in southern Sweden. But the temperature 
alone does not give a true idea of the conditions in South Polar 
regions, and the following example will serve to illustrate some 
other points of view. I had arranged a row of bamboo rods on the 
glacier, in order to measure the changes in the height of the ice caused 
by thawings and snowfalls. During the winter this height was found 
to be constant, and not the slightest part of the snow which then fell 
remained on the glacier. But during the summer, on the other hand, 
the height of the snow covering increased by 25 centimeters (9.75 
inches) and this amount still remained when we left these tracts one 
year later. 

Thus the reader must imagine a climate where winter is as severe 



THE SHAPE OF THE EARTH 169 

as winter in western Siberia, and so stormy that every particle of 
snow blows away; where the summer, even in the low latitudes 
where we were, is as cold as near the North Pole, and is, moreover, 
such that snowdrifts and glaciers increase during the warmest season 
of the year (335- 253-54)- 

Nordenskjold's camp, where he took these observations, 
was, apparently, about 64 S. Lat., or more than a thousand 
miles from the pole. 

From this account it is evident that while a little melting 
may occur from time to time in Antarctica (and some has 
been recently reported), such melting must be entirely in- 
consequential. As to the quantity of precipitation over the 
whole continent, the following considerations seem impor- 
tant. First, the low temperature means a comparative lack of 
humidity in the air; precipitation could not equal that in 
temperate or tropical regions, for cold air will not hold as 
much moisture as warm air. Second, wind pattern and topog- 
raphy are both important factors. The wind pattern is as 
follows: There are winds blowing toward the pole at high 
elevations; these have, of course, crossed oceans on their way 
to the pole, and have picked up moisture. As they approach 
the pole they are compressed and chilled, and they contract 
and lose moisture in the form of snow. The air, now having 
greater density, sinks to the ice surface and moves outward in 
anticyclonic pattern. Winds blow outward in all directions 
from the pole, bearing with them great quantities of snow. 
Much of the snow is borne out to sea, but much is deposited 
in every nook and cranny, in all declivities, and, from the 
beginning of the growth of the icecap, the fringing coastal 
mountain chains have aided in the storage of snow. They do 
not prevent the high-altitude winds, bearing their moisture, 
from entering the continent, but they do, naturally, interfere 
to some extent with the outward-flowing, low-altitude winds, 
forcing them to deposit snow. 

Now, these conditions have naturally been the same since 
the beginning of the growth of this continental icecap, and 
they must have prevailed with the previous icecaps. But we 



170 EARTH'S SHIFTING CRUST 

see that the icecap has accumulated nonetheless, and that it 
is now accumulating. Thus we can safely conclude that these 
anticyclonic winds have not prevented, and can never prevent, 
the continuing growth of the ice sheet. 

One other factor may limit the accumulation of ice. Ice- 
bergs break off from the icecap every year in great numbers, 
and it has even been suggested that they may amount to 
roughly the entire annual deposition of snow upon the conti- 
nent. How far this is from representing the true state of 
affairs can be determined from the following considerations. 

In the first place, the icebergs form, it is generally agreed, 
because the ice sheet is flowing slowly outward from the pole 
in all directions, by the effect of gravity. The ice has accumu- 
lated in the central area of the continent to a great but as yet 
unknown depth, and from this central area the surface of the 
ice sheet slopes gently downward toward the coasts. It is 
recognized that what sets the ice sheet in motion is not the 
slant of the land it lies on (it would move even if the land 
were all flat) but the angle of the slope of its own surface: 
the gradient (87:46). This being the case, two factors govern 
the speed of movement: the more gradual the gradient, the 
slower the ice flows, while the colder the ice, the greater its 
viscosity and its resistance to movement. Now, in Antarctica 
it has been observed that the gradient is only one third of the 
gradient in Greenland, where, despite a more rapid move- 
ment of the ice, the glacier still maintains itself approxi- 
mately in a static condition. The Antarctic, in addition, is 
much colder, and therefore its ice is more viscous, more rigid, 
more resistant to motion. What the temperatures deep in the 
icecap are is at present unknown, but they are probably con- 
siderably lower than those in the northern glaciers. Coleman 
notes how much slower is the movement of ice in Antarctica 
than it is in Greenland (87:44). (See n. i, p. 192.) 

Brown has correctly pointed out that a large production of 
icebergs, such as we note in Antarctica, is a sign of an expand- 
ing glacier, while a dwindling supply of icebergs is evidence 
of an icecap in decline (54). Einstein was of the opinion that 



THE SHAPE OF THE EARTH 171 

the flow-off of icebergs could not even be an important factor 
in reducing the rate of the annual increment of ice on the 
glacier (128). The general problem of the Antarctic icecap 
may be summarized thus: 

First, we know that there is never any considerable melting 
of snow in Antarctica. We have radioelement evidence of an 
enormous expansion of the icecap there in recent millennia. 
We also have evidence that it is now accumulating. We can 
add that studies carried out by Captain Charles W. Thomas, 
of the United States Coast Guard, of the radiolaria (minute 
organisms) contained in samples of bottom sediments from 
the Antarctic have recently convinced him that * 'during the 
last 5,000 years the waters surrounding this continent (Ant- 
arctica) have been getting colder" (411) just as would have 
to be expected with a growing icecap. 

Secondly, if Antarctica has always been at the South Pole, 
what conceivable factor could have operated to prevent the 
formation of an icecap there until the comparatively recent 
Eocene Period, only about 60,000,000 years ago? Once an 
icecap had formed, what other factor could have interrupted 
the glaciation, so as to bring about the growth of luxuriant 
forests there in later periods? Since it has been shown that 
climatic zones like the present have clearly existed during 
the whole of geological history (Chapter III), would we not 
be justified in expecting the icecap to have accumulated con- 
tinuously in Antarctica at least since the first known pre- 
Cambrian ice age, about two billion years ago? 

Thirdly, Campbell has made the significant observation 
that the Antarctic icecap never melts, yet we know that ice 
sheets elsewhere on the globe have melted again and again. 
It has proved impossible to account for the ice sheets that 
once existed and melted away in areas now near the equator. 
Campbell points out that even if the rate of snowfall in 
Antarctica is low compared with the precipitation in warmer 
climates, yet the icecap has, in the oceans, an unlimited sup- 
ply. It follows that, if the present icecap is not large enough 



172 EARTH'S SHIFTING CRUST 

to start a movement of the crust, it will simply continue to 
grow, drawing upon the endless resources of the oceans until 
it is big enough. 



3. A Suggestion from Einstein 

From the foregoing, it is clear that there is a basis for the 
presumption that the Antarctic icecap is largely an uncom- 
pensated mass (an extra weight on the surface of the earth), 
that it has grown continuously since the disappearance of 
nonglacial conditions in the Ross Sea area only a few 
thousand years ago, and that it is growing now. Einstein 
recognized, in the Foreword to this book, the centrifugal 
momentum that such an uncompensated mass, situated eccen- 
trically to the pole, would create when acted upon by the 
earth's rotation, and he saw that the centrifugal momentum 
would be transmitted to the crust. But he also raised, in the 
last paragraph of the Foreword, another interesting question. 
If an icecap can have such an effect, so can any other uncom- 
pensated mass. It is necessary to investigate any existing dis- 
tortions within the crust itself and to learn whether it may 
contain uncompensated masses of a magnitude comparable to 
the Antarctic icecap, and thus capable of causing comparable 
centrifugal effects. For the inference is obvious: if such masses 
are in existence, but have not moved the crust, it follows that 
the crust may be anchored too solidly to be moved by the 
centrifugal effect of icecaps. 

One of the troubles with the theory of isostasy is that the 
failures of the crust to adapt to gravitational balance have 
been found to be more numerous and more serious than ex- 
pected. Daly lists and discusses a large number of them. It 
appears, for example, that the whole chain of the Hawaiian 
Islands, with their undersea connecting masses of heavy 
basalt, are uncompensated (97:303). These islands rise from 
the deep floor of the Pacific, and their peaks tower two and a 
half miles above sea level. Their gigantic weight rests upon 



THE SHAPE OF THE EARTH 173 

the crust, and under the weight the crust has bent down 
slightly, but it has not given way. This is the more remark- 
able since the islands appear to be several million years old. 
It indicates that at this point the earth's crust is strong 
enough to bear a very considerable weight without yielding. 
The Great Rift Valley of Africa, which we have already dis- 
cussed, is uncompensated, despite its great age (97:221). 
There are also enormous anomalies in the East Indies. Ac- 
cording to Umbgrove, Vening Meinesz found that the nega- 
tive anomalies (that is, the deficiency of matter) in the great 
ocean deeps in that area and the positive anomalies on each 
side caused a total gravity deviation of 400 milligals. One 
milligal, according to Daly, would amount to about 10 
meters of granite (97:394), so that the total deflection of the 
crust from gravitational balance here would amount to 4,000 
meters of granite, or, roughly, three miles of granite, which, 
in turn, would be the equivalent of an ice sheet about nine 
miles thick. And the crust has borne this enormous strain, 
apparently, for some millions of years. According to Daly, 
the Nero Deep, near the island of Guam, has deviations from 
gravitational balance of the same magnitude (97:291). Among 
uncompensated features on the lands are the Harz Moun- 
tains, in Germany (97:349), and the Himalayas, which stand 
about 864 feet higher than they should (97:235). A particu- 
larly interesting case is that of the island of Cyprus, of consid- 
erable size, which stands about one kilometer, or 3,000 feet, 
higher than it should, and yet shows no signs of subsiding. 
Daly says: 

From Mace's table of anomalies and from his map, it appears 
that we have here a sector of the earth, measuring more than 225 
kilometers in length and 100 kilometers in width, and bearing an un- 
compensated load equal to one kilometer of granite, spread evenly 
over the sector. . . . (97:212-13). 

These facts would appear to argue a very considerable 
strength of the crust to resist the pressure toward establish- 
ment of gravitational, or isostatic, balance. However, in all 
the cases so far mentioned it is true that the deviations have 



174 EARTH'S SHIFTING CRUST 

occurred in comparatively narrow areas. The Hawaiian 
Islands, for example, represent a long, narrow segment of the 
crust. Obviously the crust can support loads with small span 
more easily than loads with a very great span. These devia- 
tions, therefore, may not tell us much about the gravitational 
status of the Antarctic icecap, which, of course, has an enor- 
mous span, since it covers a whole continent. Since they are 
insignificant quantitatively as compared with the possible 
effect of the continental icecap of Antarctica, they will not, 
of themselves, answer Einstein's question. 

Of more importance are isostatic anomalies of broad span, 
and these are, surprisingly, quite plentiful. Daly mentions 
one along the Pacific coast. This is a negative anomaly 
a deficiency of mass. Daly explains that according to one 
formula (the "International Formula"), it covers an area 
2,100 miles long, and 360 to 660 miles wide; according to 
another formula (the "Heiskanen"), it is reduced to one half 
both in intensity and in extent (97*371). Taking the lesser es- 
timate, the deficiency of mass over this large area still amounts 
to the equivalent of a continuous ice sheet 1,000 to 1,200 feet 
thick. So it appears that over this large span the crust can bear 
that amount of negative weight (that is, of pressure from with- 
in the earth) without giving way, at least for a short period of 
time. In other parts of the United States there are positive 
anomalies of the same magnitude, and these obtain over large 
areas. 

A far more extraordinary case is an enormous area of nega- 
tive mass that covers part of India and most of the adjacent 
Arabian Sea. The width of the negative area in India is 780 
miles. Daly, after noting the challenge presented by this 
fact to the whole theory of isostasy, goes on to say: 

The situation becomes even more thought provoking when we 
remember that Vening Meinesz found negative Hayford anomalies 
all across the Arabian Sea, 2500 kilometers in width. Apparently, 
therefore, negative anomalies here dominate over a total area much 
greater than, for example, the huge glaciated tract of Fenno-Scandia 
[Finland and Scandinavia]. And yet there is no evidence that the 



THE SHAPE OF THE EARTH 175 

lithosphere under India and the Arabian Sea is being upwarped. 
The fact that Fenno-Scandia, though less (negatively) loaded than the 
Arabian Sea-India region, is being upwarped, as if by isostatic adjust- 
ment, emphasizes the need to examine the Asiatic field with particular 
care. . . . (97-365)- 

Let us remember that a negative load means simply pres- 
sure from within the earth outwards, and positive load pres- 
sure from the surface inward. In principle, they are the same 
in so far as their evidence for the strength of the crust goes. 
It seems that here the crust is quite able to bear a large load 
over a great span without yielding. Daly points out that many 
parts of India are distorted on the positive side; there is an 
excess of matter over considerable areas, and he remarks: 

. . . India, among all the extensive regions with relatively close 
networks of plumb-bob and gravity stations, is being regarded by 
some high authorities as departing so far from isostasy that one 
should no longer recognize a principle of isostasy at all. . . . (97:224- 
*5). 

A particularly important aspect of these great deviations 
from gravitational balance of the crust in India is that they 
are not local distortions, not the result of local surface fea- 
tures such as hills and valleys. These surface features may 
well once, and quite recently, have been in good isostatic bal- 
ance. The distortion lies deeper: 

... In India practically all the gravity anomalies seem to have 
no apparent relation to local conditions. Only one explanation 
seems possible that is, that they are due to a very deep seated gentle 
undulation of the lower crustal layers underlying all the super- 
ficial rocks; it is evidently a very uniform, broad sweeping feature 
at a great depth, and must be uncompensated, since if it were 
compensated it would cause no anomaly at the surface (97:241-42). 

Forced to find some way of explaining how the crust could 
bear such loads (positive and negative) in India and still yield 
easily to isostatic adjustment in other areas, Daly suggests 
that the strength of the crust in India might be explained by 
a recent lateral compression of the whole peninsula, which, 



176 EARTH'S SHIFTING CRUST 

he says, is evidenced by the folding there of the young sedi- 
mentary rocks (97:391-92). 

Daly does not suggest a possible cause for this lateral com- 
pression of the whole peninsula; such a compression, part of 
the process of mountain building, he has already character- 
ized as "utterly mysterious." But it must be clear that it is 
precisely the type of distortion that might be expected to re- 
sult from a displacement of the earth's crust. Such a move- 
ment could very well account both for the depression of 
lower India and for the uncompensated elevation of the 
Himalayas. It can be said, moreover, that no displacement of 
the crust could possibly take place without creating, at some 
points on the earth, precisely such deep-lying gentle undula- 
tions of the crust. 

But still another point may be urged in support of this 
solution of the problem. We shall see, later on, that the last 
movement of the crust appears to have been approximately 
along the goth meridian, with North America moving south- 
ward from the pole. This movement would have subjected 
India to maximum displacement and to maximum compres- 
sion. In this last movement India would have been moved 
across the equator and northward toward the pole, to its 
present latitude. 

Daly's suggestion that compression may increase the tensile 
strength of the crust opens up most interesting possibilities. 
We may find here, in connection with the theory of crust dis- 
placement, a solution to very puzzling problems of isostatic 
theory. The crust of the earth shows enormous differences 
from place to place in its degree of isostatic adjustment and 
in its sensitivity to the addition or removal of loads. Apply- 
ing Daly's suggestion, we may infer that the differences may 
owe their origin to recent displacements of the crust. Areas 
recently moved poleward, having undergone compression 
and still retaining compression, would, according to Daly's 
suggestion, have greater strength to sustain the distortions; 
areas recently displaced equatorward, having undergone 
extension, or stretching, would have less strength to resist 



THE SHAPE OF THE EARTH 177 

gravitational adjustment, and, moreover, the widespread 
fracturing accompanying the movement would facilitate ad- 
justment. 

This suggestion of Daly's also has great significance for the 
understanding of the absence of much volcanism in the polar 
regions. It has been observed that these regions are relatively 
quiet, with respect to volcanoes. There is only one volcano in 
the whole continent of Antarctica, so far as we know. What 
can be the reason for this? It may be thought that this may 
result from the polar cold, but this cannot be true. The influ- 
ence of surface temperatures penetrates only a short distance 
into the crust; volcanoes originate from greater depths. The 
solution may be found in the fact that, according to our 
theory, both the present polar areas are areas that were 
moved poleward in the last movement of the crust, and were 
therefore compressed. Consequently, the crust in those areas 
was less fractured and now has greater strength to prevent 
volcanic action. This increased strength may also have the 
effect of adding to the ability of the crust to sustain the in- 
creasing weight of the icecap, without giving way, thus tend- 
ing to add to the uncompensated proportion of the icecap. In 
addition, Antarctica may well show isostatic distortions of 
the crust itself, equivalent to the positive anomalies in India. 

The importance of finding a reasonable solution for the 
profound contradictions in the theory of isostasy has been 
emphasized by several recent writers. Professor Bain, of Am- 
herst, writes: 

Isostatic adjustment exists only in imagination. I present the ex- 
istence of peneplains in witness thereof. Establishment of the 
Rocky Mountain peneplain or the Old Flat Top Peneplain of the 
western states requires erosion of at least 10,000 feet of the rock over 
the main arch of the Front Range. The rivers wore the land down 
slowly to grade equilibrium without observable rise of the unloaded 
region or subsidence of the loaded region throwing all gravity out 
of equilibrium. Then in the brief interval of a small part of a 
geological epoch the land surface rose to re-establish near gravity 
equilibrium. . . . (19). 



178 EARTH'S SHIFTING CRUST 

Now, as I understand Professor Bain's statement, his point 
is that in numerous instances erosion has worn away moun- 
tain ranges, leaving flat plains (peneplains), and in the in- 
stance he cites it seems that during the prolonged period 
when the erosion was taking place (erosion that resulted in 
removal of no less than 10,000 feet of rock from one area, and 
the deposition of the resulting sediments in another), the 
crust did not respond by rising in the first area and sinking 
in the second. Gravitational balance was thus sadly set askew, 
and remained so for a long time. Then, relatively suddenly, 
equilibrium was re-established. How do we explain this? 

I think it is necessary to take into consideration the fact 
that just as compression will be at a maximum along the 
meridian of displacement of the crust in the poleward direc- 
tion, extension or stretching will likewise be at a maximum 
along the same meridian in the equatorward direction. But, 
in both cases, areas removed from this meridian will be dis- 
placed proportionately less, and large areas will undergo very 
little or no displacement, and consequently very little or no 
compression or extension. Since, as we saw in the last chapter, 
successive movements of the crust may oscillate along merid- 
ians placed close together, it follows that, for long periods, 
compression may be sustained in particular areas and isostatic 
adjustment impeded in those areas. Eventually, a movement 
of the crust in a different direction will permit the delayed 
adjustment to take place. 

In this way, too, we may explain the data upon which Dr. 
Jeffreys based his conclusion that isostasy is an exceptional 
condition of the earth's surface, which is re-established only 
at long intervals. The theory presented in this book offers a 
solution for the cause of the geological revolutions which, 
he supposed, shattered the crust at long intervals, bringing 
about the formation of mountains, and permitting the re- 
establishment of crustal balance. 

With regard to the vast negative or positive distortions of 
isostasy, the displacement theory has a solution to offer. Let 
us suppose a movement of the crust causing widespread slight 



THE SHAPE OF THE EARTH 179 

distortion of the earth from its equilibrium shape, distortion 
such as now prevails across parts of India and all of the 
Arabian Sea. It is essential to realize that the long persistence 
of such anomalies, and the apparent lack of any tendency to 
adjustment, may have no relationship to the strength of the 
crust. It may be due, quite simply, to the fact that the matter 
in the sublayer (the asthenosphere) is too viscous to flow 
rapidly, and that when it has to flow such great distances, and 
in such great volume as would be required to compensate the 
sweeping undulations of the geoid caused by a movement of 
the crust, great periods of time are required, periods so long 
that our instruments have not been able to detect the progress 
of isostatic adjustment. 

The advantage of the theory of crust displacements is that 
it can reconcile the data supporting the conviction of geolo- 
gists that the crust must be too weak to support major loads 
out of adjustment over great spans of territory, with the ob- 
served fact that in some cases it appears to do so. Further- 
more, we may, with this theory, grant the crust enough 
strength under certain conditions (of compression) to sup- 
port heavy loads of narrow span, such as the Hawaiian 
Islands, and still understand its extreme weakness in areas of 
extension, where it appears to adjust easily to rather minor 
loads. 

Einstein, in the Foreword, referred to the possible centrif- 
ugal effects of these distortions within the crust. The follow- 
ing principles apply: 

a. A positive load on the crust, like the icecap, will exert a 
centrifugal effect equatorward; correspondingly, the 
effects of negative loads must be poleward. 

b. The effects of positive loads on one side of the equator 
will be opposed to the effects of positive loads on the 
other side of the equator; equal positive loads in equal 
longitudes and latitudes will cancel each other across the 
equator, and the same is true of negative loads. 



i8o EARTH'S SHIFTING CRUST 

c. Despite the fact that such loads may cancel each other 
wholly or in part, in so far as the transmission of a net 
centrifugal momentum to the crust in any given direc- 
tion is concerned, nevertheless their opposition will in- 
volve the creation of persisting stresses in the crust, and 
these may be a cause of seismic activity. 

d. Crustal distortions, unlike icecaps, are comparatively 
permanent features; many may persist through one or 
more displacements; their effect will change quantita- 
tively according to their changes of latitude and longi- 
tude. 

e. At the termination of each crustal movement, the dis- 
tortions of the rock structures of the crust should be 
approximately balanced across the equator. In a period 
of several thousand years following such a movement, 
however, the process of isostatic adjustment, proceeding 
faster in some areas than in others, may disturb this 
balance and predispose the crust to a new displacement. 

f. We may conclude, in answer to the question raised in 
the Foreword, that while some of these distortions are 
massive, they tend to be balanced across the equator, 
and that the principal disturbing factor, from the 
quantitative standpoint, must in all probability be the 
rapidly growing continental icecap. 



4. The Triaxial Shape of the Earth 

We cannot leave the subject of the gravitational adjustment 
of the earth's surface without mentioning the greatest dis- 
tortion of all, the triaxial deformation of the earth. It is all 
the more important to consider this question since here we 
shall see, at one and the same time, a solution for one of the 
greatest of geological conundrums, and one of the most 
powerful arguments in support of the theory of displace- 
ments of the earth's crust. 

Not long ago, scientists became aware of the fact that there 



THE SHAPE OF THE EARTH l8l 

is a deviation in the shape of the earth from the idealized 
form of a flattened, or oblate, spheroid. The increasingly 
accurate measurements of geodesy have shown that the earth 
has bumps and irregular lumps in various places, which seem 
to correspond to a third axis running through the earth. As 
a result of this, scientists now consider that the true shape 
of the earth is that of a "triaxial ellipsoid." 

An axis, of course, is not a material thing. It is only a line 
that somebody imagines running through a sphere to give a 
dimension to that sphere in that direction. Three axes of the 
earth mean one through the poles, on which the earth rotates 
(the axis of rotation); one through the equator, called the 
equatorial axis, twenty-six miles longer than the polar axis; 
and now a third axis, roughly through the equator, at an 
angle to the other equatorial axis. 

The result of having two axes of different lengths running 
through the equator is, of course, that the equator itself is a 
little flattened; it is oval, rather than truly circular. The flat- 
tening is very slight. According to Daly, one axis through the 
equator is 2,300 feet longer than the other (97:32); Jeffreys, 
according to Daly, prefers half that figure. Daly finds that the 
longer diameter through the equator (the major axis) runs 
from the Atlantic Ocean, at 25 W. Long., to the Pacific, at 
155 E. Long., and the shorter diameter (or minor axis) runs 
from the western United States, at 115 W. Long., to the 
Indian Ocean, at 65 E. Long. (97:32). Just as the actual 
amount of the flattening of the equator is uncertain, so are 
the precise situations of the major and minor equatorial 
axes. More recently, determinations by the United States 
Coast Geodetic Survey have suggested a slightly different 
position for one of these axes. Moreover, the third axis ap- 
parently does not run precisely through the equator. The 
result is that the earth's shape is distorted by protuberances 
of various sizes and shapes. If we take Jeffreys's estimate of 
their magnitude, we see that they amount to the equivalent 
of about 2,000 feet of rock, or over a mile of ice, and of 



182 EARTH'S SHIFTING CRUST 

course the anomalies have enormous spans, on the order of 
thousands of miles. 

Despite their vastly greater magnitude, these triaxial pro- 
tuberances have one thing in common with those in India. 
Just as Daly observed that the Indian anomalies must result 
from sweeping undulations of the geoid at some depth in the 
crust, underlying all the surface features, so do the triaxial 
protuberances indicate distortion in depth rather than at the 
surface. In India the surface features would be in fairly 
good isostatic adjustment if the deep-seated undulations were 
disregarded, while the geodesist Heiskanen, according to 
Daly, found that if he disregarded the triaxial protuberances 
if he regarded the triaxial ellipsoid as the natural shape of 
the earth all his anomalies were reduced to one half, both 
in extent and in intensity (97:368). 

It does not seem reasonable simply to disregard distortions 
of the shape of the earth of this magnitude, unless we have an 
explanation of them that is convincing. Daly provided an ex- 
planation, but for a number of reasons it seems to me unsatis- 
factory. 

It was plain to him that the strength of the crust could 
not possibly support such enormous distortions over such 
spans. Therefore he made one or two alternative suggestions, 
advancing them as possibilities only. He suggested, first, that 
assuming an original molten condition of the earth, it is 
possible that the material in the liquid melt was not of uni- 
form density on opposite sides of the earth, and that there- 
fore when the mesosphere (the inner solid shell underlying 
the asthenosphere) solidified, it was heavier on one side than 
on the other that is, lopsided and the resulting unevenness 
of gravity at the surface influenced the equilibrium, that is, 
the elevation from place to place, of the surface layers. This 
is an ingenious suggestion, but it requires the assumption of 
the cooling of the earth, which is itself doubtful. Thus this 
particular explanation rests upon speculation, and upon 
speculation that is not well supported. 

The same is true of Professor Daly's second suggestion. He 



THE SHAPE OF THE EARTH 183 

supposes that the lopsidedness of the internal shell may have 
resulted from the separation of the moon from the earth, at 
which time the bed of the Pacific may have been created. 
The arguments that once supported this theory of the origin 
of the moon have, in recent years, been gradually whittled 
away, until little remains of them. This, then, is also a haz- 
ardous speculation. 

Professor Daly's fertile mind has produced a third sugges- 
tion. He feels that perhaps the triaxiality may have resulted 
from the effects of continental drift, which he felt himself 
compelled to support because there was no other way to ex- 
plain the innumerable facts of paleontology and geology, 
many of which have been already cited in this book. We have 
seen, however, that continental drift will not do. 

It seems that all the arguments that Professor Daly uses to 
support his suggestion that the triaxial protuberances are not 
supported by the crust, but from below the crust, fail to stand 
examination. They are supported by no convincing mass of 
evidence. There is obviously a sort of desperate urgency 
about them. A strong need impels him to hoist them up. The 
nature of this need is perfectly clear. 

The need is to save the theory of isostasy. It is to smooth 
the path in front of a theory that has a lot of useful applica- 
tions and has a great deal to be said for it. The theory is 
threatened by the unexplained anomalies referred to above; 
it is still more threatened by these massive distortions of 
the shape of the planet, the triaxial protuberances. They are 
wholly and absolutely irreconcilable with the known prin- 
ciples of physics, as opposed to speculations. Either the shape 
of the earth is established by the balance of the force of grav- 
ity and the centrifugal effect of the rotation, or it is not. The 
geoid, so established, is distorted, and it proves impossible 
to explain the distortion either by the resistance of the crust 
to the aforementioned forces or by the (undemonstrated) lop- 
sidedness of the internal shell. 

But displacements of the earth's crust may explain the 
matter, and in the simplest possible fashion. 



184 EARTH'S SHIFTING CRUST 

We have seen that areas displaced poleward in a movement 
of the crust will be elevated relatively to sea level. Two areas 
will be displaced poleward at the same time, one to each pole, 
and both will be elevated somewhat with reference to the 
equilibrium surface. The distance through the earth between 
these points will be increased slightly. At the same time, two 
other areas will be displaced equatorward. They will subside, 
and the diameter through the earth between them will be 
shortened to some extent. These areas will be centered on 
the meridian of the movement of the crust. At 90 degrees' 
remove on each side from this meridian, there will be no 
movement; here are the so-called "pivot areas*' that do not 
change their latitude. They will therefore not change their 
elevation: a diameter through the earth between them will 
be unchanged. 

As the consequence of this, we see that in one direction 
the diameter of the earth through the equator is shortened; 
in the other direction through the equator it is not. The re- 
sult must inevitably be the ellipticity, or ovalarity, of the 
equator. 

The consequences of the displacement do not end here. As 
we have stated from time to time, much complicated folding 
and faulting of the crust, much shifting of matter below the 
crust, would be inevitable or likely, and these would have 
effects at the surface, including basining and doming. Hence, 
some of the protuberances now being discovered may have 
nothing to do with the triaxial distortions, and may simply 
be confused with them. 

Now, it is clear that this explanation of the triaxiality re- 
quires neither complicated and hazardous speculations about 
the earth's interior nor an incredible strength in the earth's 
crust. The protuberances remain because the matter below 
the crust is too highly viscous to flow the great distances and 
in the great volume that would be required to re-establish 
the normal shape of the earth: that is, it is too viscous to have 
been able to do so in the very short period that has elapsed 
since the last movement of the crust. But no doubt the read- 



THE SHAPE OF THE EARTH 185 

justment is proceeding slowly; no doubt the triaxial bumps 
are now the reduced remnants of those that existed at the 
end of the last movement of the crust. 

If all anomalies in the crust cause centrifugal effects, then 
these vast triaxial protuberances must do so. These must, as 
I have pointed out, be balanced across the equator, or have 
been so at the termination of the last movement. Since then, 
isostatic adjustment has probably been proceeding, and 
therefore the balance of forces established when the crust 
stopped moving may now no longer exist. The instability of 
the crust may have been thereby increased, and the effects of 
its instability may supplement the increasing thrust of the 
growing, eccentric icecap. This suggests that the balance of 
the crust in its present position may be only a "trigger bal- 
ance." 



5. The State of Matter Below the Crust 

The theory presented in this book depends upon the rela- 
tionship between three factors: the quantity of the momen- 
tum transmitted to the crust by the icecap, the tensile 
strength of the crust, and the degree of weakness prevailing 
in the subcrustal layer, or asthenosphere. In Einstein's opin- 
ion, the existence of sufficient weakness in the asthenosphere 
to permit the displacement of the crust was the only doubtful 
assumption of the theory. However, we find that one and the 
same assumption is required for this theory, and for the 
whole theory of isostasy. It is my opinion that the theories 
stand or fall together. 

In conceiving of the asthenosphere, we should not imagine 
a layer of soft rock distinguished from the crust and from the 
inner shells of the earth by sharp lines of demarcation. In- 
stead, one grades off insensibly into another, and in all prob- 
ability inequalities in thickness exist from place to place. 

It is the general opinion of geophysicists that at a certain 
depth in the crust increasing heat and pressure bring about a 



i86 EARTH'S SHIFTING CRUST 

diminution of the tensile strength and rigidity of the rock. 
The decline of strength continues to the bottom of the crust. 
Dr. Jeffreys remarks: ". . . At some depth ... it begins to 
decrease and may be a tenth of that of surface rock at a depth 
of 30 miles. . . ." (238:202). 

At the bottom of the crust, perhaps about 36 miles be- 
low the surface of the earth, an important change of state 
apparently takes place. The heat reaches the melting point 
of the rocks, and the rocks can no longer crystallize. Since the 
strength of rocks depends mostly upon a structure of strong, 
interlocking crystals, the change of state implies a disappear- 
ance of strength. For this reason Professor Daly considers the 
asthenosphere to be "essentially liquid/' ". . . For it is 
hardly to be doubted that a rock layer, too hot to crystallize, 
has only a minute strength, or no strength whatever" (97:399- 
400). 

Jeffreys is in agreement that the melting point of rock 
should be reached about 36 miles down (238:140), judging 
from the heat gradient. 

If it were only a question of the crystalline or noncrystal- 
line structure of the rock, we would readily conclude that 
the asthenosphere could offer no serious resistance to the dis- 
placement of the crust. The crust would be truly (to use Ein- 
stein's term) a "floating crust." 

But we must also take into account another quality of mat- 
ter, which is viscosity. Materials possess varying degrees of 
viscosity. Viscosity can make a liquid act like a solid. If, for 
example, a high diver hits the surface of the water at a bad 
angle he may kill himself, because the water, though liquid, 
requires time to flow, and if the impact is too sudden there 
is no flow and the liquid acts as a solid. Tar is an example 
of a more viscous substance. Taffy candy is highly viscous, 
and can be cut with scissors, and yet, given a certain amount 
of time, it will flow like a liquid. The effect of pressure on 
different substances is to increase their viscosity, to make 
them stiffer. They will then resist sudden shocks better, but 
will flow like liquids if subjected to steady pressure for a con- 



THE SHAPE OF THE EARTH 187 

siderable period of time. The layer immediately under the 
earth's crust is subjected to high pressure, and therefore, 
although it is liquid, it may be stiff. The stiffness can be ex- 
pected to be least immediately under the crust, and to in- 
crease with increasing depth. 

However, it cannot be assumed that the viscosity imme- 
diately under the crust is very great. Bridgman has pointed 
out that it depends to a great extent on the particular chem- 
ical composition of the rocks, which necessarily is uncertain 
(50). Moreover, though pressure increases viscosity, heat 
diminishes it, again differently for different chemical sub- 
stances. It is difficult to estimate the net effect of the opera- 
tion of these opposite influences at any point under the crust. 

Daly presents evidence that the viscosity of the astheno- 
sphere must be very low. He cites, first, evidence from the 
edges of the area recently occupied by the Scandinavian ice- 
cap. According to isostatic principles, viscous rock must have 
flowed out from under the section of the crust loaded by the 
icecap. If the rock was very stiff, Daly argues, it would not 
have flowed very far, but would have upheaved the crust 
around the fringes of the ice sheet. Evidences of such up- 
heaval should be observable, but there are none. He thinks 
that there should have been an upheaval of the Lithuanian 
plain, but none occurred. Hence his conclusion is that the 
asthenosphere must have low viscosity: ". . . And there is 
no apparent necessity for excluding the possibility of effec- 
tively zero strength*' (97:389). 

The meaning of this geological evidence appears to be 
that the asthenosphere must be a true liquid in terms of 
pressure applied over periods of the length required for the 
growth of the Scandinavian icecap, which would be the same 
length of time that we suppose would be involved in a dis- 
placement of the crust. 

As a second line of evidence for a weak sublayer, Daly 
points out (as already mentioned) that in mountain making 
the crust is folded to its full depth, that horizontal sliding has 
to occur to permit this folding, and that horizontal sliding 



188 EARTH'S SHIFTING CRUST 

would be impossible if the asthenosphere had any consider- 
able strength. In his opinion mountain formation requires 
the existence of a zone of easy shear. 

Thirdly, Daly urges the importance of the general body 
of evidence of igneous geology: 

. . . The existence of a liquid or approximately liquid astheno- 
sphere is strongly suggested by the countless facts of igneous geology. 
The hypothesis that the lithosphere is crystalline, a few scores of 
kilometers in maximum thickness, and everywhere underlain by a 
hot vitreous substratum provides what appears to be the best work- 
ing theory of the chemical nature of magmas and their modes of 
eruption. ... In general, no petro-genetic theory that does not rec- 
ognize a specific world-encircling asthenosphere of this kind has 
been found to explain so many facts of the field. . . . (97:399-400). 

Among specific evidences that point, in Daly's opinion, to a 
really liquid asthenosphere are the plateau basalts, which, 
as we have seen, were formed by immense floods of liquid 
magma that engulfed hundreds of thousands of square miles 
of the surface at one time. 

Jeffreys opposes Daly's view of the asthenosphere, and ar- 
gues for continuation of considerable strength to a depth of 
several hundred miles. Daly notes his argument, and an- 
swers it. 

Jeffreys's argument is based on the fact that an analysis of 
earthquake waves shows that some earthquakes originate at 
depths up to 420 miles below the surface. Presumably, they 
can originate only as the result of fracture in a solid substance, 
which necessarily would have some strength. Daly remarks: 

For example, Jeffreys deduces, from the reality of deep-focus shocks, 
a strength of about 1000 kilograms per square centimeter for the 
material reaching down to the 7oo-kilometer level at least. This 
is about the strength of good granite in the testing machine. 

To reconcile that conclusion with the demonstrated degree of 
isostatic equilibrium, Jeffreys suggests that isostasy is a highly ex- 
ceptional condition of the earth. He assumes the condition to have 
been established during major orogenic disturbances, and preserved 
for only a relatively short time after each paroxysm of mountain- 
making (97:400-01). 



It is not easy to reconcile Jeffreys's views here with those 
: his I have quoted above regarding the decline of strength 
: rock with increasing pressure in the crust. It is evident 
iat if Jeffreys is right, the theory of isostasy is reduced to 
shambles. But Daly presents a counterargument to show 
iat he is not right. He suggests that at great depths the vis- 
>sity would be so high that a comparatively sudden ac- 
imulation of strain from some cause could fracture the rock 
if it were a solid. Laboratory experiments conducted by 
ridgman have shown that solids subjected to pressures so 
eat as to make them flow behaved in very peculiar fashion, 
hey would flow, but the flow would, at times, be interrupted 
f fracture and slip. Daly also quotes Gutenberg to the effect 
iat ". . . Whereas at normal depths the accumulation of 
rain is made possible by the strength of the rocks, at the 
eater depths the high coefficient of viscosity is sufficient, 
id no conclusion as to strength can be drawn" (97:403). 
hus the counterargument is a strong one. All that is neces- 
ry, in fact, both for the theory of isostasy and for the theory 
: displacements of the crust is a thin layer of extreme weak- 
*ss at the top of the asthenosphere, where the viscosity 
ould be much less than at the greater depths. 
According to Daly, Jeffreys adopted his view because he 
>uld see no reason for the development of sudden stresses 
the greater depths. Daly argues that this cannot settle the 
atter; perhaps we shall eventually discover a sufficient 
Luse. Daly also says, when speaking of the earth's triaxiality, 
iat it means "stress at depths of thousands of kilometers" 
7:404). Putting two and two together, I would suggest that 
ie deep-focus earthquakes result from the triaxiality, and 
iat the stresses develop suddenly enough to exceed the lim- 
5 of the viscosity at that depth and cause fracture, because 
te triaxial bulges are not permanent features of the planet, 
it recent deformations, which must set up strains at con- 
ierable depths. 
Archibald Geikie describes experiments done a long time 



190 EARTH'S SHIFTING CRUST 

ago, which are still suggestive of the probable behavior of 
material in the asthenosphere: 

The ingenious experiments of M. Tresca on the flow of solids 
have thrown considerable light on the internal deformations of rock- 
masses. He has proved that, even at ordinary atmospheric tempera- 
tures, solid resisting bodies like lead, cast iron, and ice may be so 
compressed as to undergo an internal motion of their parts, closely 
analogous to that of fluids. Thus a solid jet of lead has been pro- 
duced, by placing a piece of the metal between the jaws of a power- 
ful compressing machine. Iron, in like manner, has been forced to 
flow in the solid state into cavities and take their shape. On cutting 
sections of the metal so compressed, their particles of crystals are 
found to have arranged themselves in lines of flow which follow 
the contours of the space into which they have been squeezed. . . . 
(170:316). 

It seems altogether unlikely that material under the pres- 
sures prevailing at the bottom of the crust, and at very high 
temperatures, could resist the shearing movement of the crust 
over it. Let us remember that in a displacement of the crust 
very little material, comparatively speaking, would actually 
have to flow. The crust would simply start to slip over the 
asthenosphere. The action would be one of gliding, the most 
economical form of motion, though, as already explained, 
the downward protuberances of continents and mountain 
chains might act to slow down the movement. 

To conclude, then, the asthenosphere could have consid- 
erable viscosity, even at the top, and yet offer no definite 
obstacle to the displacement of the crust. Once the crust 
started to move, the braking influence of the viscosity would 
steadily decline, for with the increasing distance of the cen- 
ter of mass of the icecap from the axis, the centrifugal effect 
would be multiplied (Chapter XII). No friction between the 
two layers could suffice to absorb this ever increasing thrust. 
It would have to continue until the motive force was re- 
moved by the melting of the icecap in the warmer latitudes. 
And, in the meantime, as Frankland has suggested, the fric- 
tion would have been productive of heat that might have 
further facilitated the movement. 



THE SHAPE OF THE EARTH 1Q1 

I have not referred to another important aspect of the be- 
havior of materials under pressure, one that may have its 
importance. If the viscosity of matter increases with pressure, 
so does plasticity. Solids become more and more plastic under 
pressure. At the bottom of the crust matter is under enor- 
mous pressure. That means that very little force may be re- 
quired to overcome its rigidity. It also means that when a 
critical point is reached, the material may deform suddenly. 
It does not give way at a speed proportional to the pressure 
applied, as khthe case of a viscous liquid, but at a speed that 
has no relationship to the applied force. Bridgman has 
pointed out that the exact degree of plasticity at the bottom 
of the crust, like that of the viscosity, cannot be determined 
because of our ignorance of the chemical composition of the 
materials. 

This question of plastic deformation raises an interesting 
possibility. What if, at a certain point in the displacement, 
viscous deformation gives way to plastic deformation? Sup- 
pose the movement starts slowly as a gliding over a viscous 
surface. Suppose it gains enough speed so that, at the inter- 
face between the crust and the underlying plastic layer, a 
plastic type of yielding occurs. The interactions here would 
be complex, but the possibility looms that at times the dis- 
placement of the crust could take place with considerable 
speed. 

I have mentioned that the gliding motion of the crust 
might be impeded at times by the downward projections of 
its undersurface. However, if there is one situation in which 
plastic deformation might be considered probable, it is one 
in which these downward projections for example, the un- 
derbody of a continent were displaced against upward pro- 
jections of the asthenosphere under the ocean basins. Here 
considerable pressures would arise, and various circumstances 
might concentrate these pressures in narrow regions and in- 
tensify them; the pressures might thus reach the critical 
point of plastic deformation, and result in the abrupt shear- 
ing off of larger or smaller segments of the downward pro- 



192 EARTH'S SHIFTING CRUST 

jections of the crustthe roots of continents and mountain 
ranges. This would result in comparatively sudden changes 
at the surface, at least in areas being moved equatorward and 
thus stretched and weakened. It would also facilitate the 
process of planing off and shaping the continental sides as 
suggested in the last chapter. 1 

i Newspaper reports of observations now being made in Antarctica, as part of 
the scientific program of the present International Geophysical Year, indicate 
a depth for the ice sheet at the South Pole of about 8,000 feet. This suggests 
that Campbell and I may have considerably underestimated the total mass 
and weight of the icecap. At the same time, the reports suggest very low pre- 
vailing temperatures, and therefore high rigidity, for the ice, at some depth 
below the surface. (See p. 170.) 



VII : NORTH AMERICA AT THE POLE 



In the preceding chapters much evidence has been presented 
to support the contention that the earth's crust has often 
been displaced. Perhaps the reader will feel that the general 
evidence is sufficient. It remains, nonetheless, to show be- 
yond a reasonable doubt that such a movement actually did 
occur in one specific instance. I have already suggested that 
the last movement may have been the immediate cause of 
the end of the last ice age in North America and in Europe. 
In this chapter I will review the evidence for this. At the 
same time, I will try to show why the circumstances of 
the displacement themselves indicate and, in fact, require the 
further conclusion that the icecap in North America must 
itself have been the agent of the displacement. 



/. The Polar Icecap 

Several independent lines of evidence, each individually ex- 
tremely impressive, unite to suggest that the Hudson Bay 
region lay at the North Pole during the so-called Wisconsin 
glaciation. 

The first line of evidence is based on the shape, and on 
the peculiar geographical position, of the last North Amer- 
ican icecap. Kelly and Dachille point out that the area occu- 
pied by the ice was similar both in shape and in size to the 
present Arctic Circle (248:39). Many geologists have re- 
marked on the unnatural location of the icecap. It occupied 
the northeastern rather than the northern half of the con- 
tinent. Some of the northern islands in the Arctic Ocean, 
and northern Greenland, were left unglaciated (87:28, note). 
Alaska and the Yukon had mountain glaciers but no con- 
tinuous ice sheet. Then, the ice is known to have been thicker 



194 EARTH'S SHIFTING CRUST 

and to have extended farther south on the low central plains 
of the Mississippi Valley than it did on the high mountain 
areas in the same latitudes farther west. But according to ac- 
cepted ideas about glaciation, if the ice age was the result of 
a general lowering of world temperatures, the ice should 
have formed first in the mountain areas, and it should have 
extended farther south on them than in the low plains. 
There has been no explanation of this, which may have been 
one of the problems that led Daly to remark that "The Pleis- 
tocene history of North America holds ten major mysteries 
for every one that has already been solved" (93:111). 

The assumption that the Hudson Bay region then lay at 
the pole would make the facts easy to explain, for in this case 
the western highlands would lie to the south of the plains 
region, and one would therefore expect thicker ice on the 
plains lying nearer the pole. Absence of continuous glacia- 
tion in Alaska and in the Arctic islands would be easily ex- 
plained. Furthermore, the fact that the European ice sheet 
was thinner than the North American and did not extend 
so far south would be understandable. The relationship be- 
tween the North American and contemporary European 
glaciations will be discussed further below. 

A second line of evidence for the position of North Amer- 
ica at the pole consists of the new data regarding recent 
climatic change in Antarctica, already discussed (Chapter II). 
A movement of the crust that would move North America 
southward about 2,000 miles would also necessarily move 
Antarctica that much nearer the South Pole (see globe). 
Therefore, a displacement of the crust accounts both for the 
deglaciation of North America and for the expansion of the 
icecap in Antarctica, and it accounts for the two events being 
simultaneous. No other hypothesis so far suggested can ac- 
count for climatic revolutions in opposite directions on the 
two continents. No assumption of ice ages resulting from a 
simultaneous world-wide reduction of temperature will fit 
the facts. In a personal interview, I once asked Einstein if 



NORTH AMERICA AT THE POLE 

he could see any logical alternative to crust displacement 
as the explanation of these facts. He replied that he was per- 
suaded of the soundness of the method of crust radioelement 
dating developed by Professor Urry, and that he saw no other 
reasonable explanation of the evidence (see page 364). A third 
line of evidence is that presented by Dr. Pauly, already dis- 
cussed (Chapter III). 

A fourth line of argument is developed by Lawrence Dil- 
lon, who shows, first, that the essential condition governing 
the growth of ice sheets seems to be not the average year- 
around temperature, nor the amount of annual precipitation, 
but the mean summer temperature (114:167). He points out 
that no ice sheets form at the present time in areas with mean 
summer temperatures of 45 F. or higher, and suggests that 
they probably didn't in the past. He cites, as a good illus- 
tration of this principle, the northeastern section of Siberia, 
which is unglaciated despite the fact that it is the "cold pole" 
of the world, and although it has a higher annual precipita- 
tion than Greenland or Antarctica. But the summer tempera- 
ture is high, and this he thinks is the controlling factor. 

Dillon points out, next, that the existence of the Wisconsin 
glacier would have demanded a decrease of 25 C. in average 
summer temperatures as they exist now (114:167). But he 
notes that according to Antevs the average temperature de- 
crease in late Pleistocene time along the iO5th meridian in 
southern Colorado and northern New Mexico as compared 
with the present was only 10 F., while (according to Meyer) 
the average temperatures during the glacial period in the 
equatorial Andes were only 5 or 6 F. lower than at pres- 
ent (114). 

Thus Dillon shows that there was no uniform decrease of 
summer temperatures during the glacial period. No world- 
wide factor, such as variations in solar radiation, reduced the 
temperature. The range of summer temperatures would be 
understandable if the ice sheet were a polar icecap, however, 
and the range appears to require that assumption. 



196 EARTH'S SHIFTING CRUST 

... On the other hand, the only apparent alternate hypothesis 
that of a uniform depression of the mean temperature of say 10 F. 
would suggest a July mean of 60 F. for the ice sheet's lower boundary, 
which is similar to that of present-day England, or northern Ger- 
many, or the State of Maine, but with somewhat colder winters. 
Since no glaciers or permanent snow fields are known to exist today 
under such mild climates, it seems scarcely likely that they could have 
done so in former times (114:168). 

Dillon does not explicitly suggest a movement of the crust, 
but he leaves no alternative. 

A fifth line of argument may be based on some evidence 
used by Wegener to support his theory of drifting conti- 
nents. He quoted the glaciologist Penck as saying that the 
Pleistocene snowline lay about 1,500 to 1,800 feet lower in 
Tasmania than in New Zealand, and added, "This is very diffi- 
cult to understand because of the present nearly equal 
latitudes of the two localities" (450: 1 1 1). Wegener, of course, 
explained the matter by his theory of continental drift. If, 
however, his theory is rejected, crust displacement may pro- 
vide a solution, for if the Hudson Bay region was then lo- 
cated at the North Pole, as we suppose, Tasmania would 
have been a good many degrees nearer the South Pole than 
New Zealand, as a glance at the globe will make plain. An- 
other bit of evidence that fits in here is the apparent retreat 
of glaciers in South Australia about 10,000 years ago (16). 

A sixth line of argument may be based on the evidence for 
world-wide volcanism at the end of the Wisconsin glacia- 
tion. Extensive volcanic activity is an inevitable corollary 
of a general movement of the earth's crust. I shall present 
the argument that the volcanism incident to the movement 
accounts for the numerous oscillations of the Wisconsin ice 
sheet, and for the following "Climatic Optimum." 

A seventh line of evidence is provided by the mass of data 
relating to changes in sea level at the end of the ice age. I 
shall attempt to show that these changes cannot be explained 
by the melting of the northern icecaps, though they may be 
explained by a displacement of the crust, on the basis of 
principles already discussed. 



NORTH AMERICA AT THE POLE 1Q7 

An eighth line of evidence is presented by the story of the 
extinctions of many kinds of animals at the end of the ice 
age, and this is so important that it will require a chapter by 
itself (Chapter VIII). Much additional evidence based on ma- 
rine and land sediments will also be presented later (Chap- 
ter IX). 



2. The Displacement Caused by the Ice Sheet 

It may be argued that convincing evidence of a displacement 
of the crust by no means requires the further conclusion that 
the movement at the end of the ice age was the result of the 
centrifugal effects of the North American icecap. A dozen 
other possibilities may be thought to exist. Several of them 
may be worth considering. Why, then, must we jump to the 
conclusion that the event was related causally to the icecap? 
There have been several suggestions to account for shifts 
of the crust by other agencies than icecaps. What is the com- 
mon element of these suggestions? It can easily be pointed 
out. All of them involve long periods of time. Gold's sug- 
gestion involves periods of the order of a million years. 
Bain's involves periods of a great many million years be- 
tween movements. Ma's involves long periods between 
movements, terminated by cataclysms. Eddington's type of 
displacement, if it could be made to work at all, would neces- 
sarily be very slow. Besides their common inability to explain 
the velocity of events revealed by the new methods of radio- 
element dating, the suggestions are unsatisfactory also because 
they are vague as regards the mechanism of displacement. 
They can be grounded neither upon detailed observations 
nor upon mathematical calculations. The mechanism devel- 
oped by Campbell, on the other hand, is quite definite and 
precise (although it, too, necessarily must involve assump- 
tions). Of special importance is the fact that Campbell's 
mechanism is capable of being checked against geological 
observations in some detail. 



198 EARTH'S SHIFTING CRUST 

To begin with, it is clear that a massive centrifugal effect 
must have been created by the Wisconsin ice sheet, if the 
considerations presented in Chapter VI are sound. Radioele- 
ment dating has shown that the ice sheet developed in a very 
short time. A high degree of isostatic compensation of the 
icecap is therefore unlikely, even if isostatic compensation 
could really eliminate the effect. 

It is significant that the Wisconsin ice sheet was asymmet- 
rical in its distribution about the center from which it spread. 
If we assume that the ice center from which the icecap 
radiated coincided at that time with the pole, then this 
asymmetrical distribution must have resulted in a centrifu- 
gal effect. Furthermore, it appears that the great bulk of the 
ice lay to the south of the ice center, and so therefore the 
direction of the resulting centrifugal thrust would have been 
southward, and the result would have been to shift the Hud- 
son Bay region due south from the pole toward its present 
latitude. This is indeed in remarkable agreement with the 
theory. The facts are reported by W. F. Tanner, writing in 
Science, under the title "The North-South Asymmetry of the 
Pleistocene Ice Sheet" (414). 

There are some comparisons between this North American 
icecap and the present icecap in Antarctica that are worth 
making. The North American icecap is thought to have cov- 
ered about 4,000,000 square miles, as compared with the 
nearly 6,000,000 square miles of the present Antarctic cap. 
It may be asked, Why should the smaller North American 
icecap have started a slide of the earth's crust, when this 
larger one in Antarctica has not? The answer to this appears 
to lie in the different degrees of eccentricity, or asymmetry, 
of the two icecaps. In Antarctica, the pole is fairly near 
the center of the continent, so that the real asymmetry of the 
icecap is not at first glance apparent. In North America the 
presumed pole in Hudson Bay or perhaps in western Quebec 
was on the eastern side of the continent, quite near the sea. 
In this situation, the icecap was more eccentric. Its center 
of gravity was in all probability much farther from the pole 



NORTH AMERICA AT THE POLE 

than is the case in Antarctica, and the centrifugal effect ac- 
cordingly would have been much greater in proportion to 
the quantity of ice. 

If the pole was situated in the Hudson Bay region, the 
closeness of the sea would have been a factor aiding the rapid 
growth of the icecap, and giving less time for possible 
isostatic adjustment. 

An additional observation worth making, perhaps, is that 
if this vast ice sheet had developed so rapidly at the present 
latitude of Hudson Bay, the centrifugal effect would have 
been colossal. If the centrifugal effect of the Antarctic icecap, 
with its center of gravity 345 miles from the pole, is sufficient 
to produce a bursting stress almost equal to the estimated 
tensile strengths of the crust, the smaller North American ice- 
cap, with its center of gravity about 2,500 miles from the 
pole, would have produced a bursting stress many times 
greater than the crustal strength. Why this must be so, the 
reader may see by referring to Figure XII (p. 343). On this 
plate, the second parallelogram represents the centrifugal 
effect of the present Antarctic icecap on the assumption that 
the icecap could be displaced, without melting, as far as the 
45th parallel of latitude. It is evident that at the 45th parallel 
the centrifugal effect would be approximately six times 
greater than the effect produced by the icecap with its center 
of mass where it is now, about 345 miles from the pole. The 
bursting stress would be increased in proportion, being al- 
ways 500 times the centrifugal effect (Chapter XI). It seems 
unreasonable to suppose that at the end of the ice age the 
crust could have withstood a stress six times greater than 
our present estimate of its strength. 

The reader is free to conclude from the foregoing, either 
that the North American icecap must have been a polar ice- 
cap (because it could never have developed to its full size at 
the present low latitude of the glaciated region without mov- 
ing the crust) or that the movement of the crust from any 
such agency is impossible. But, as we have seen (Chapter VI), 



goo EARTH'S SHIFTING CRUST 

he would have trouble in finding a reasonable basis for the 
latter conclusion. 

We can therefore conclude that, on the whole, the North 
American icecap is a good candidate for the position of prime 
mover in the last displacement of the crust. The argument 
will be strengthened when we consider, below, its detailed 
history, and the implications of the extraordinary tempo of 
its development and of its subsequent decay. The essential 
argument in favor of icecaps is the time factor, for the rate 
of their accumulation and of their melting is obviously many 
times faster than that of any other process creating unbalance 
in the distribution of materials on the earth's surface. 

Horberg has recently collected and studied, as already 
mentioned, the radiocarbon dates bearing on the history of 
the Wisconsin ice sheet. According to him, the following is 
its short and violent history (222:281): 

a. The first known advance of the icecap its first ap- 
pearance in Ohio is dated at merely 25,100 years ago. This 
is called the "Farmdale Advance." It was formerly thought 
to have occurred as much as 100,000 or even 150,000 years 
ago. This date, then, cuts the time for the later history of 
the ice sheet by about three quarters. Six different radiocar- 
bon dates, all of the Farmdale Advance, show that the ex- 
pansion continued until at least 22,900 years ago, or for 
about 3,000 years. Then there was an unexplained interval 
of warm climate (which I will explain later on), called the 
"Farmdale-Iowan Interstadial." This warm period lasted 
about 1,500 years, during which the ice withdrew a certain 
distance. 

b. Following the recession, a new advance of the icecap 
occurred. This is referred to as the "lowan Advance." It 
began about 21,400 years ago, lasted about 700 years, and 
was interrupted by a new recession about 20,700 years ago. 

c. This second recession, after less than a thousand years, 
was succeeded by an extremely massive advance during the 
period from 19,980 to 18,050 years ago. These dates must 
not be taken as absolutely exact; there is always a small mar- 



NORTH AMERICA AT THE POLE 2O1 

gin of error. This new expansion, called the "Tazewell Ad- 
vance/' apparently carried the Wisconsin icecap to its maxi- 
mum extension and greatest volume. 

d. The Tazewell Advance was interrupted by a prolonged 
period of warmth and recession called the "Brady Interval" 
or "Brady Interstadial." This lasted between three and four 
thousand years. It began before 16,720 years ago, and ended 
sometime after 14,042 years ago. The ice retreated a long 
way. 

e. A fourth advance of the ice sheet beginning about 
13,600 years ago, and continuing to about 12,120 years ago 
(called the "Gary Advance"), was followed by the "Two 
Creeks Interstadial," an interval of warmth and recession, 
about 11,404 years ago. 

f. A fifth advance of the ice, referred to as the "Mankato 
Advance," appears to have taken place between 10,856 and 
8,200 years ago. The high point of this advance is called the 
"Mankato Maximum." Another writer, Emiliani, finds that 
a sixth expansion of the ice sheet, the "Cochrane Advance," 
took place less than 7,000 years ago (132). 

g. There was a sudden, virtually complete disappearance 
of the ice sheet (which had, however, according to Flint, been 
getting thinner ever since the Tazewell Advance) (375:177). 
It disappeared in an extraordinarily short period, as shown 
by a postglacial date from Cochrane, Ontario, 6,380 years ago. 

h. The significance of the postglacial date from Ontario 
(close to the center of the former ice sheet) is increased when 
we compare it with the date of the postglacial Climatic Op 
timum, which Flint finds to have occurred between 6,000 and 
4,000 years ago. The climate during the Optimum, according 
to Brooks (52:296-97), averaged about 5 degrees warmer 
than at present. There is a very difficult problem here of ac- 
counting for the velocity of these events. It is obvious that 
the cold glacial climate of North America must have warmed 
up to something like the present prevailing temperatures 
before it could warm up still further to the point reached 
in the Optimum. But if so, could the whole wanning process 



2O2 EARTH'S SHIFTING CRUST 

have taken place in 380 years? It seems probable that the 
Cochrane Advance was local and minor. The Mankato Max- 
imum, however, was not. The entire transformation of the 
climate must then have taken place in about 2,000 years. 
In this short interval a continental icecap disappeared. It 
had been growing thinner for a long time, to be surefor 
about 10,000 years, since the Tazewell Advance but its final 
dissolution was sudden. Compared with the usual geological 
time concepts, even the period of 10,000 years for the decline 
of the ice sheet from the end of the Tazewell Advance is in- 
credibly rapid. Horberg, as I have mentioned, has pointed 
out that if the radiocarbon method is valid, the rate at which 
the ice must have advanced and retreated indicates that geo- 
logical processes (especially meteorological processes like 
rainfall) must have been greatly accelerated during the ice 
age. Now it is easy to show that these processes inevitably 
would have been accelerated by a movement of the crust; 
we shall return to consider this matter in detail below. 

As a matter of fact, it is not necessary to depend wholly 
upon radiocarbon dating to establish the extraordinary ve- 
locity of the geological events of the ice age. Professor Urry's 
method of radioelement dating, used to date the cores ob- 
tained by Hough from Antarctica and elsewhere, shows pre- 
cisely the same thing: the datings obtained by this method 
indicate several rapid glaciations and deglaciations of Ant- 
arctica, and correlated world-wide changes of climate. We 
will consider these again in Chapter IX. 

A third line of evidence tending to the same effect is pre- 
sented by Emiliani, who has applied a technique of deter- 
mining ancient temperatures of sea water that was developed 
by Harold C. Urey. Urey's method is based on an isotope 
of oxygen. Emiliani has noted many important temperature 
changes in a comparatively short period during the latter 
part of the Pleistocene; he has reached the conclusion that 
the four known Pleistocene glaciations all occurred in the 
last 300,000 years. He agrees essentially with Horberg as to 
the date of the beginning of the Wisconsin glaciation (132). 



NORTH AMERICA AT THE POLE 2OJ 

Assuming the radiocarbon dates to be correct, then, we 
find that at the end of the Tazewell Advance there was a 
recession, and that despite the readvances the ice gradually 
thinned until the ice sheet disappeared. This can be ac- 
counted for by the assumption that the crust was in motion, 
and that it continued to move slowly during all or most of 
the 10,000 years during which the icecap was in intermittent 
decline. As I have already pointed out, there is no other 
reasonable explanation for the disappearance of the ice sheet. 
But the assumption is strengthened by a most remarkable 
fact. It would have to be considered probable, as following 
naturally from the theory, that as the crust moved there 
would be a period, possibly prolonged, when the melting on 
the equatorward side of the icecap would be balanced and 
even more than balanced by further build-up of the icecap 
on the poleward side. Thus, as the Wisconsin icecap moved 
southward, build-up of the ice would continue on its north- 
ern side. The result would be that the ice center, the center 
of maximum thickness, from which the ice sheet would move 
out by gravity in all directions, would be 'displaced to the 
north. And this is exactly what happened. Coleman writes: 

Two important facts have been established by Low, who worked 
over the central parts of the Labrador sheet: first, that the center of 
the glaciation shifted its position, at one time being in Lat. 51 or 
52, later in Lat. 54, and finally in Lat. 55 or 56. Instead of beginning 
in the north and growing southward it reversed this direction; 
second, that the central area shows few signs of glaciation, so that 
the pre-glacial debris due to ages of weathering are almost undis- 
turbed. A broad circle around it is scoured clean to the solid 
rock. . . . (87:117). 

There really could be no more eloquent confirmation of 
the southward displacement of the earth's crust. We see veri- 
fication here of one of the important mechanisms of displace- 
ment as suggested by Campbell, which is that the continuing 
build-up of the ice sheet on its poleward side as it moves 
away from the pole will be a factor in prolonging the move- 
ment. This may, indeed, result in the prolongation of the 



204 EARTH'S SHIFTING CRUST 

movement until the arrival of an oceanic area (in this case, 
the Arctic Ocean) at the pole. As to the second fact that, ac- 
cording to Coleman, was established by Low, I shall suggest 
an explanation later (Chapter VIII). 



). The Cause of the Oscillations of the Ice Sheet and 
the Cause of the Climatic Optimum 

But what about the alternating phases of retreat and read- 
vance of the ice sheet? The retreats can be explained, of 
course, by the assumption that the icecap was moving slowly 
into lower latitudes with the displacement of the crust. But 
how are the readvances to be explained? Up to the present 
there has been no explanation for these. 

I have already suggested that a corollary of any crust dis- 
placement is an increase of volcanic activity. There have 
been times in the past, however, when the quantity of vol- 
canic action has been extraordinary (231:629). As an exam- 
ple of this, there appears to be evidence that in a small area 
of only 300 square miles in Scandinavia during Tertiary 
times there may have been as many as 70 active volcanoes at 
about the same time. Bergquist, who cites the evidence, re- 
marks, "Volcanic activity on this scale, erupting through 
about 70 channels, and concentrated in a relatively short 
period, must have been very impressive" (31:194). 

It seems likely that a phase of intense volcanism would be 
favored where a sector of the crust was moving toward the 
equator, and undergoing stretching (or "extension") together 
with widespread fracturing, for we must remember that this 
pulling apart of the crust would permit the release of many 
pre-existent strains, the upward or downward adjustment of 
blocks that had been held out of isostatic adjustment for a 
longer or shorter time. There would certainly be a general 
rise of igneous matter into millions of new fractures, and 
occasionally this could result in overflows at the surface, in- 
cluding, as has already been pointed out, vast lava floods. 



NORTH AMERICA AT THE POLE 205 

A special phase of the volcanism must now attract our at- 
tention. Most volcanoes produce dust, sometimes in vast 
quantities (87:271). This dust is rapidly distributed through 
the atmosphere. The effects of volcanic dust on the climate 
have been the subject of intensive studies (231, 375). We must 
stop for a moment to summarize the essential results of these 
studies. 

The fundamental work on the relationship of volcanic 
dust to climate is The Physics of the Air, by Humphreys, 
which has been cited in earlier chapters. Humphreys shows 
that volcanic dust can have a remarkable effect in lowering 
temperature. He points out that the effect of the particles 
depends upon whether they happen to be more efficient in 
intercepting the sun's light and reflecting it back into space 
than they are in preventing the radiation of the earth's heat 
into outer space. What is important is the size and shape of 
the dust particles as compared with the wave lengths of the 
radiation. Particles of a given length will have great re- 
flecting and scattering power on sunlight, and none on the 
radiation of heat from the earth (which, of course, is not 
in the form of light). Humphreys concludes that it is neces- 
sary to determine the approximate average size of the indi- 
vidual grains of floating volcanic dust, as well as the wave 
lengths of the radiation involved. He accomplishes this satis- 
factorily. After mathematical treatment of the various factors 
he concludes: ". . . the shell of volcanic dust, the particles 
all being of the size given, is some thirty fold more effective 
in shutting out solar radiation than it is in keeping terrestrial 
radiation in. . . ." (231:580). He also points out: 

. . . The total quantity of dust sufficient ... to cut down the 
intensity of solar radiation by 20% ... is astonishingly small only 
i74th part of a cubic kilometer, or the 727th part of a cubic mile. . . . 
(231:583). 

This, of course, means that the sun's radiation is reduced 
to this extent over the whole surface of the earth. It re- 
quires only a few days for volcanic dust projected into the 



206 EARTH'S SHIFTING CRUST 

upper atmosphere to be distributed around the world. Ap- 
parently, the amount of dust produced by the eruption of 
Mt. Katmai in Alaska in 1912 was sufficient slightly to lower 
the temperature of the whole earth's surface for a period of 
two or three years (87:270; 231:569). For long-range effects 
a continuous series of explosions would be necessary, because 
volcanic dust settles out of the atmosphere in periods of the 
order of three years. Humphreys presents a great deal of evi- 
dence correlating variations in average annual global tem- 
peratures through the nineteenth century, with specific vol- 
canic eruptions. He establishes the fact that the eruptions 
certainly had an important influence. 

If this is true of our times, what should we expect to result 
from the activation of very great numbers of volcanoes dur- 
ing a displacement of the crust? Not only would the tempera- 
ture fall, and perhaps very drastically, but continuing vol- 
canic outbursts would keep it low. At the same time, the 
alternation of periods of massive outbursts with periods of 
quiet would produce violent variations of the climate, be- 
tween extremes of cold and warmth. 

Here we have our explanation of the five or six major 
readvances of the Wisconsin ice sheet (there were, appar- 
ently, many more minor ones). In all probability, they re- 
sulted from the long continuation of massive outbursts of 
volcanism. The readvances of the ice are explained by vol- 
canism, and the volcanism is explained by the displacement 
of the crust. 

It is not necessary, however, for us merely to assume with- 
out evidence that there must have been unusual volcanic 
activity at the end of the ice age. On the contrary, there is a 
rather remarkable amount of evidence of excessive volcanism 
during the decline of the Wisconsin icecap. It comes from 
many parts of the earth. For North America it is particularly 
rich. From radiocarbon dating we have learned that during 
the last part of the ice age there were active volcanoes in our 
northwestern states. One of the greatest eruptions was that 
of Mt. Newberry in southern Oregon less than 9,000 years 



NORTH AMERICA AT THE POLE 

ago (242:23). Other late glacial or early postglacial volcanic 
activity in Oregon was reported by* Hansen (199). Farther 
south the story is the same: 

In Arizona, New Mexico and southern California there are very 
fresh looking volcanic formations. The lava flow in the valley of the 
San Jose River in New Mexico is so fresh that it lends support to 
Indian traditions of a "river of fire" in this locality (235:113). 

Volcanic disturbances in South America about 9,000 years 
ago have been dated by radiocarbon (242:45). Huntington 
reported "lava flows of the glacial period interstratified with 
piedmont gravel" in Central Asia (232:168). Ebba Hult de 
Geer quoted Franz Firbaz as follows: "The volcanic erup- 
tions that produced the Laacher marine volcanic ash are 
about 11,000 years old, or a little older. . . ." (108:515). 
Hibben suggested that the extinctions of animals in Alaska 
at the end of the ice age may have been due to terrific vol- 
canic eruptions there, of which the evidence is plentiful 
(218). We will return to his account later. 

Volcanic dust is not the only important product of volcanic 
eruptions. They also produce vast quantities of carbon diox- 
ide gas. Tazieff, for example, estimated that in one eruption 
he observed in Africa, along with about seventy-eight mil- 
lion tons of lava, the volcano emitted twenty billion cubic 
yards of gas (416:217), not all of which, of course, was carbon 
dioxide. 

The carbon dioxide emitted by volcanoes has an important 
effect on global temperature, but one quite different from 
the effect of the volcanic dust. Being a translucent gas, it does 
not interfere with the entrance of sunlight, of radiant heat, 
into the atmosphere. But it is opaque to the radiation of 
the earth's heat into outer space. A small quantity of the 
gas will act effectively to prevent loss of heat from the earth's 
surface. A considerable increase in this small percentage will 
tend to raise the average temperatures of the earth's surface. 

Carbon dioxide differs from volcanic dust also in the fact 
that because it is a gas it will not settle out of the atmosphere. 



2o8 EARTH'S SHIFTING CRUST 

It will remain until, in the course of time, it is absorbed 
by the vegetation, or by chemical processes in the rock sur- 
faces exposed to the weather. Therefore, as compared with 
volcanic dust, carbon dioxide is a long-range factor, and its 
effect is opposite to that of the dust. 

In any displacement of the crust it follows that massive 
outbursts of volcanism must have added to the supply of 
carbon dioxide in the air. Its proportion in the atmosphere 
must have finally been raised far above normal. In conse- 
quence, it is likely that whenever volcanic activity declined 
sufficiently to permit a warming of the climate, the high 
proportion of carbon dioxide in the air may have acted to 
intensify the upward swing of the temperature. This would 
have increased the violence of the oscillations of the climate, 
and would have accelerated many geological processes. 

Evidence that the proportion of carbon dioxide in the air 
was, in fact, higher toward the end of the ice age than it is 
now is provided by recent studies of gases contained in ice- 
bergs. Scholander and Kanwisher, writing in Science, re- 
ported that air frozen into these bergs, presumably dating 
from the ice age, showed lower oxygen content than air has 
at the present time, and theorized: 

Possibly this ice was formed as far back as Pleistocene time, when 
cold climates may have curbed the photosynthetic activity of green 
plants over large parts of the earth, resulting in a slight lowering 
of the oxygen content of the air (368:104-05). 

The weight of a great deal of evidence presented in this 
book is opposed to this particular speculation; we must sup- 
pose, on the contrary, that the earth's surface as a whole was 
then no colder than it is now, and that just as many plants 
were absorbing carbon dioxide and releasing oxygen into 
the air then as now. But the same fact the lower proportion 
of oxygen may perhaps be explained by supposing a higher 
proportion of carbon dioxide, especially if we assume a mas- 
sive increase in the proportion of that gas in the air. 

Another consideration that greatly strengthens this line of 



NORTH AMERICA AT THE POLE 2OQ 

thinking about the carbon dioxide is that the assumption of 
a cumulative increase in the proportion of the gas in the air, 
during the movement of the crust and the waning of the ice 
sheet, helps to explain not only the extraordinarily rapid 
final melting of the ice but also the succeeding Climatic 
Optimum. 

The Climatic Optimum is the most important climatic 
episode since the end of the ice age; the fact of the occur- 
rence is well attested, but it is unexplained. Scientists have 
been aware that this 2,ooo-year warming of the climate could 
have resulted from an increase in the carbon dioxide con- 
tent of the air, but this has not been helpful, since hitherto 
no way has been found by which to account for an increase 
of the required magnitude. No other possible cause of the 
warm phase (such as an increase in the quantity of the sun's 
radiant heat) has been supported by tangible evidence. It 
seems that the assumption of a displacement of the crust 
furnishes the first possibility of a solution. 

To return, for a moment, to the question of the several 
readvances of the ice, it may be asked, Why did the volcanism 
occur in massive outbursts separated by quieter periods? 
Why was it not continuous through the whole movement of 
the crust? Campbell has suggested an answer. It is quite 
possible that the fracturing of the crust, necessary to permit 
the displacement, was itself spasmodic. We may assume that 
when the mounting bursting stress brought to bear on the 
crust by the growth of the icecap finally reached the critical 
point (that is, the limit of the crust's strength), considerable 
fracturing occurred in a rather short time, accompanied by 
massive volcanism. The crust would now start to move, and 
it would continue to move easily to the distance permitted 
by the extent of the fractures so far created. The movement 
might then come to a halt, and the accompanying volcan- 
ism would tend then to subside. Meanwhile, on the pole- 
ward side of the icecap the ice still would be building up, 
and the bursting stress resulting from it would again be on 
the increase. New fracturing would eventually occur, with 



210 EARTH'S SHIFTING CRUST 

a new outburst of volcanism, and the movement would be 
renewed. In the intervals between phases of intense vol- 
canism the dust would settle out of the air, the carbon diox- 
ide would take effect, and the climate would rapidly grow 
warmer. This warm "interstadial," however, would affect 
different sides of the icecap differently; it could cause im- 
portant recessions of the ice sheet on the equatorward side, 
and at the same time, because of the accompanying rise in 
humidity, it could augment the snowfall on the poleward 
side. 

The crust would continue to move, even though with each 
recurring warm period the ice sheet grew thinner, because 
the icecap, at each successive stage, would have been moved 
farther from the axis of rotation, so that the effects of the 
diminishing quantity of the ice would be effectively coun- 
terbalanced by the multiplication of the centrifugal effect 
per unit volume of the remaining ice (see Chapter XI). 

Finally a time would come when the rising temperatures 
of the lower latitudes and the accumulation of carbon di- 
oxide would so far exceed the refrigerating effects of vol- 
canic outbursts that the latter would become impotent to 
maintain the icecap. With the reduction of the icecap below 
a certain point, the crust would cease to move, volcanic dis- 
turbance would decline, the air would be cleared of dust, 
and within a short time the accumulated carbon dioxide 
would usher in the warm phase of the Optimum. The story 
ends with the absorption of the carbon dioxide by the vege- 
tation, the reduction of its percentage to normal, and the 
establishment of a climate like the present. 



4. The Glaciation of Europe 

Further confirmation of the position of North America at 
the pole during the Wisconsin glaciation comes from Eu- 
rope. Radiocarbon dating has revealed some very interesting 



NORTH AMERICA AT THE POLE 211 

facts about the relationship of the American and Scandi- 
navian glaciers. 

It has been shown, by Flint (375:175) and others, that 
there is a correspondence in the timing of the phases of 
advance and retreat of the ice on both sides of the Atlantic. 
This is exactly what we should expect, considering that the 
causes of the oscillations, the volcanic dust and the carbon 
dioxide, were world-wide in their effects. 

But despite this synchronism, there is also an important 
difference between the two glaciations: it is clear that the 
icecap in Europe underwent proportionately greater diminu- 
tion with each phase of the recession after the Tazewell 
Maximum. The assumption that the glaciations on both 
sides of the Atlantic were in all respects precisely contempo- 
rary, that they advanced and retreated equally at equal times, 
has now produced contradictions of a very glaring character. 
It has placed two specialists, Ernst Antevs and Ebba Hult de 
Geer, at odds with each other. 

The basis of the contradiction is as follows: The late hus- 
band of Ebba Hult de Geer, Gerard de Geer, was the author 
of the so-called "Swedish Time Scale." This is a method of 
geological dating based on countings and comparisons of an- 
nually deposited layers of clay (varves) in lakes. De Geer first 
developed the method more than a generation ago. In a 
number of instances datings established by it have been well 
confirmed by the more recent radiocarbon method. 

De Geer found that by about 13,000 years ago the Scandi- 
navian icecap had retired from Germany and England, and 
that the ice front lay across Sweden. It is obvious that its 
withdrawal from Germany and England must have started 
thousands of years earlier. By 13,000 years ago a large per- 
centage of the whole European icecap was gone. In America, 
however, the reduction of the Wisconsin icecap had pro- 
ceeded nowhere near so far. Twice again, after this, the 
American icecap expanded in the Gary and Mankato Ad- 
vances. The great icecap, though thinner, still occupied most 
of its original area. 



212 EARTH'S SHIFTING CRUST 

Now, what Dr. Antevs says is that the radiocarbon dates 
from America don't make sense, and the radiocarbon method 
must be wrong (9:516). He attacks the method because the 
rates of withdrawal of the ice which it suggests are to him 
fantastic. He complains particularly about the disproportion 
in the indicated speeds of withdrawal in America and Eu- 
rope. The radiocarbon method has indicated that the Man- 
kato Maximum occurred between 11,000 and 10,000 years 
ago. This stage has been related chronologically to the so- 
called Salpausselka Stage in Europe. Antevs considers this 
totally unreasonable, because 

This correlation equates a point at less than one-quarter of the 
American ice-sheet radius with one at the half way mark in Europe. 
Clearly this lop-sided matching cannot be right. 

He says, further: 

Other implications are equally unreasonable. . . . The Canadian 
ice sheet would still have touched Lake Superior when the Scandina- 
vian ice sheet had entirely disappeared. . . . 

Antevs makes the conflict more explicit, as follows: 

The North American ice sheet would still have extended to the 
middle of the Great Lakes when the Scandinavian ice sheet had en- 
tirely disappeared, for the latter had melted from the Angermanalven 
basis by 8550 B.P. [Before the Present], and from Lapland by 7800 
B.P., and what is more, the ice would still have lingered in these lakes 
while the distinctly warmer Altithermal [Climatic Optimum] came 
and went. The ice retreat would have been exceedingly slow during 
the Altithermal but extraordinarily rapid during the last 3500 years, 
which have been only moderately warm (9:519). 

Antevs is therefore driven into a blank rejection of radio- 
carbon dating. He insists, in contradiction to all such datings, 
that the icecap must have left the Canadian Mattawa Valley 
about 13,700 years ago, and that the Mankato Maximum 
(which he refers to as the Valders Maximum) must have oc- 
curred about 19,000 years ago (9:520). In the discussion in 
the pages of the Journal of Geology, between him and Mrs. 
de Geer, Mrs. de Geer insists on the high reliability of the 



NORTH AMERICA AT THE POLE 

radiocarbon method and on the general agreement of the 
radiocarbon dates with the dates found by the Swedish Time 
Scale. With regard to the date of the Mankato Advance chal- 
lenged by Antevs, she says: 

The whole method of C 14 determinations, however, is taken up 
by America's most clever research men and practiced very critically 
most of all the special test at Two Creeks. As they were startled 
by the low figures of years obtained, they repeated the investigation 
several times. As the same value always recurred, such critical persons 
might well have examined eventual deficiencies of the material 
before publishing a result regarded generally as unbelievable. Since 
such a procedure was not found necessary, the test is probably reliable, 
although many others may be doubtful (108:514). 

However, Antevs succeeds in making it plain that some of 
the late Dr. de Geer's dates, as found by the method of count- 
ing clay varves, are inconsistent with radiocarbon dates. 

Now here is a shocking conflict between experts, each with 
years of experience in the field and direct access to all the 
relevant data. How can it be resolved? It seems very likely 
that the evidence stressed by both is largely, though not en- 
tirely, sound. Yet the difference between them is a major 
difference. 

This contradiction may be resolved by the simple assump- 
tion that North America lay at the pole during the Wiscon- 
sin period. By this assumption, Europe would have been a 
long way south of the Hudson Bay region. As I pointed out 
earlier, the thinner European ice, and the fact that it did not 
reach so far south as ice did in America, can be accounted 
for in this way. The more rapid retreat of the European 
glacier is entirely understandable on the assumption that it 
occupied a lower latitude. The simultaneous phases of re- 
treat and advance, then, and the faster general retreat of the 
European glacier are both understandable. 

This problem of the relationship of the American and 
European glaciations raises another question. Why was it 
that, with a pole in Hudson Bay or western Quebec, Great 
Britain and Scandinavia were glaciated at all, since Scan3i- 



EARTH'S SHIFTING CRUST 

navia at least must then have lain somewhat farther from 
the pole than it does now? Furthermore, why did Alaska 
then have many great mountain glaciers, but no continuous 
ice sheet? The latter problem is intensified by the considera- 
tion that the particular movement of the crust that we are 
supposing here, while it lowered the latitude of eastern North 
America a great deal, must have slightly raised the latitude 
of Alaska, especially that of northern Alaska. The reader 
can make these relationships clear to himself by referring 
now to a globe. We are assuming the displacement to have 
occurred along the goth meridian. 

The explanation of the glaciation of northwestern Europe 
is, I think, as follows. First, the heaviest glaciation of Europe 
is not contemporary with the Wisconsin ice sheet, but was 
the consequence of an earlier polar position, which will be 
discussed further on (Chapter IX). Secondly, the compara- 
tively thin European ice sheet of Wisconsin time (which in 
Britain consisted really only of discontinuous mountain gla- 
ciers) was made possible by a very special combination of 
meteorological conditions. In North America a vast icecap 
extended eastward from its center near Hudson Bay. Much 
of the continental shelf in this whole area was then above 
sea level, as, indeed, it should have been to agree with our 
general theory, and this was covered by ice. Then the anti- 
cyclonic winds, blowing outward in all directions from the 
icecap, had only to cross the narrow North Atlantic, raising 
moisture from the sea and depositing it upon Scandinavia 
and Britain. 

At first glance it might seem that a pole in Hudson Bay 
would have involved a heavy glaciation of Greenland, but 
there are reasons to suppose that it might, on the contrary, 
involve a deglaciation. Depending on the precise location of 
the pole, parts of Greenland would have lain farther from 
it than they do from the present North Pole. Of greater im- 
portance, however, is the fact that the Arctic Ocean would 
have been a temperate, and even, on the Siberian side, a warm 
temperate, sea. It would be likely, in these circumstances, 



NORTH AMERICA AT THE POLE 215 

that a warm current like the Gulf Stream would have been 
flowing at that time out of the Arctic and down the coast of 
Greenland. Such a warm current might easily have degla- 
ciated the island (or rather, islands). It might, however, have 
been deflected from Scandinavia and the British Isles by land 
masses in the North Atlantic, to be discussed later on. 

If this deglaciation, indeed, reflects what really happened 
in Greenland, then there must have been a warm interval in 
Europe between the period of massive glaciation, to be dis- 
cussed later, and the much less severe glaciation of late Wis- 
consin time. The present glaciation of Greenland would have 
been the consequence of the passage of the pole from the 
Hudson Bay region to its present location, with the refrig- 
eration of the Arctic Ocean. The final warming of the cli- 
mate both in Europe and in America would have been the 
consequence of the disappearance of the North American 
icecap, and of the pattern of anticyclonic winds which it had 
created. 

So far as the glaciation of Alaska is concerned, again, the 
climate there was colder than it is now because of the vast 
refrigerating effect of the icecap that covered 4,000,000 
square miles of the continent. Just as, at present, the Antarc- 
tic icecap makes the South Polar region colder than the Arc- 
tic (because it is a perfect reflector of the sun's radiant energy 
back into space), so then the great Wisconsin icecap meant 
that the prevailing temperatures at the center of the ice 
sheet (presumably the pole) were much lower than the tem- 
peratures prevailing now at the present North Pole, where 
no great icecap exists. But, although the intensely cold anti- 
cyclonic winds blowing off the Wisconsin icecap made Alaska 
colder than it is now, and thereby produced larger glaciers 
than exist at present, still these winds blew only over con- 
tinuous land, and not over the sea, and so they could not 
pick up the moisture required to produce a continuous ice 
sheet. This explains why Alaska warmed up at the end of 
the North American ice age, even though it actually may 
have moved closer to the pole. 



2i6 EARTH'S SHIFTING CRUST 

Another interesting argument is used by Antevs to buttress 
his position against radiocarbon dating. It is based on the 
evidence of crustal warping at the end of the ice age. Radio- 
carbon dating would, he says, require a fantastic rate of 
crustal warping, considered impossible by geophysicists. He 
says: 

My dating of the Cochrane stage at 11300-10150 B.P. is directly 
supported by the fact that long ages were required for the crustal 
rise which has occurred in the region since its release from the ice, 
At the south end of James Bay the rise of land relative to sea-level 
amounts to 600700 feet. . . . The upward movement of some 650 
feet equals the rise of the Scandinavian center of uplift during the 
last 8,200 years. Since the rates of modern uplifts are similar, 01 
one meter a century in the Scandinavian center, and probably 70-80 
centimeters (2.3-2.6 feet) a century at James Bay, the past rates ma} 
also have been similar. Since, furthermore, the uplifts in the two 
regions may have been essentially equal in general, the regression of 
the shore line in the James Bay region by some 650 vertical feet 
must have taken several thousand years, perhaps 8,000-10,000 
years. . . . (108:520). 

However, a displacement of the crust, with America moved 
farther than Europe, would solve this problem. Processes of 
adjustment of the crust would have a velocity proportional 
to the amount of the displacement of the particular area. B) 
assumption, North America was displaced more than 2,ooc 
miles to the south, but the southward displacement of the 
glaciated area in Europe amounted to only about 500 miles, 
The assumption of crust displacement offers the first possi- 
bility of reconciling the observed rates of crustal warping in 
America with geophysical principles. 



5. Changes in Sea Level at the End of the Ice Age 

There was a remarkable number of changes in the elevation 
of lands, and their interconnections, at the end of the ice age 
The idea that they can all be explained either by a general 
rise of sea level due to the melting of ice or by the isostatic 



NORTH AMERICA AT THE POLE 217 

rebound of the areas after the ice left is, however, fallacious. 
Let us consider, first, the question as to how far the melting 
of ice, raising the sea level, can solve the problem. 

The new radioelement data from Antarctica, as we have 
seen, strongly suggest that the huge total quantity of ice 
supposed to have existed during the ice age is an illusion. It 
now appears that while the glaciers were at their maximum 
in North America a large part of Antarctica was ice-free. 
This is the only reasonable interpretation of the Antarctic 
data. It is therefore doubtful that the amount of ice then was 
very different in amount from that existing now. We have 
noted that for about 10,000 years the Wisconsin ice sheet was 
growing thinner, until its final disappearance. If this was the 
result of the southward movement of the icecap if North 
America was then moving southward Antarctica must, at 
the same time, have been moving into the Antarctic Circle. 
Therefore, as the ice sheet gradually thinned in North Amer- 
ica, as it withdrew in Europe, the Antarctic icecap must have 
been in process of expansion. The water released by the melt- 
ing in North America may have been mostly locked up again 
in the gathering Antarctic snows. 

It follows from this that the process, during a period of 
perhaps 10,000 years, was simply one of transfer of ice masses 
from the Northern Hemisphere to Antarctica. It is difficult 
to say whether the tempos of melting in North America and 
of accumulation in Antarctica were always closely in line, 
or which may have been faster. No doubt alternations took 
place. In consequence, there may have been minor fluctua- 
tions of sea level, without a major universal rise. 

Yet such a rise of the sea level in some parts of the world 
did take place. It has already been pointed out that such 
changes must accompany a displacement of the crust. We 
have merely to decide which method of accounting for the 
facts is most reasonable. 

If the rise of the sea was due to melting ice, it should, ad- 
mittedly, have been quantitatively proportional to the quan- 
tity of the ice that is assumed to have melted. It should, of 



2i8 EARTH'S SHIFTING CRUST 

course, have been the same in all parts of the world (allow- 
ing some differences, perhaps, for vertical movements of the 
land locally). It should have been universal that is, the evi- 
dences should be observable everywhere, on all the conti- 
nents. There is, however, strong evidence in conflict with 
each of these propositions. 

The maximum rise in sea level that can be ascribed to the 
melting of the Pleistocene ice sheets (assuming that the Ant- 
arctic icecap existed contemporaneously with them) is about 
300 feet. This is a liberal estimate. Yet, in a recent study, 
Fisk and McFarlan show that the sea level during the Wis- 
consin glaciation (on American coasts) was 450 feet below 
the present level (153:294-96). Moreover, according to them, 
this is a minimum estimate, and the probabilities favor a 
greater lowering of the sea level in the late Pleistocene. Still 
more interesting, they give a chart showing that the lowest 
sea level was earlier than 28,000 years ago, or considerably 
before the maximum of the Wisconsin ice sheet. This date 
was established by radiocarbon (153:281). It can only mean 
that the low sea level must be attributed to a cause other 
than the withdrawal of water from the ocean to form that 
ice sheet. 

Furthermore, Fisk and McFarlan show that the sea was 
rising 20,000 years ago, before the completion of the massive 
Tazewell Advance that carried the Wisconsin icecap to its 
maximum size (153:298). Surely, if the sea level were con- 
trolled by the glaciers, it should have been falling. Finally, 
Fisk and McFarlan show that the sea level had risen to 
within 100 feet of its present level by 10,000 years ago. Yet 
we know that by that time the Wisconsin glaciation was a 
mere shadow of its former self, while the Scandinavian had 
virtually ceased to exist. Is it likely that the remnants of these 
ice sheets could later have raised the ocean level 100 feet? 
The question is rendered even more doubtful by a news 
item that comes to me while I write these lines. It is a dis- 
patch to the New York Times by John Hillaby, dated from 
Sheffield, England, September 2, 1956, giving an account of 



NORTH AMERICA AT THE POLE 

the meeting of the British Association for the Advancement 
of Science. Hillaby describes a paper by Professor Harold 
Godwin of Cambridge University in which the professor 
gives the results of extensive research into the question of 
the date of the separation of England from the Continent. 
The date has been found to be 5,000 B.C., or 7,000 years ago. 
The report shows that the research work was very thorough. 
Now, obviously, by 7,000 years ago the Scandinavian icecap 
was long since gone, and the North American ice sheet was 
reduced to a few Canadian remnants. Yet only now did the 
North Sea bottom sink, and the English Channel become 
flooded by the sea. There is evidently something wrong here. 
There is a suggestion here that the floodings were produced 
by readjustments of the crust, and not by glacial melt water. 

There is evidence that the sea rose (or the land subsided) 
farther on the western than on the eastern side of the At- 
lantic. This, of course, suggests that the development was 
not related to an increase of melt water. A good deal of this 
evidence was presented years ago by J. Howard Wilson, in 
his interesting Glacial History of Nantucket and Cape Cod 
(454). Wilson argued that eastern North America must have 
stood from 1,000 to 2,500 feet above its present level during 
the ice age. If we take the lesser estimate and compare it with 
the findings of Fisk and McFarlan (which they give as 
minima only) we can see that they are in pretty good agree- 
ment. Coleman was in agreement with Wilson, but based 
his opinion on the evidence of submarine canyons, which, as 
I have already mentioned, may have been created by fractur- 
ing of the crust rather than by subaerial erosion and subse- 
quent subsidence. Wright and Shaler, however, presented 
evidence for a 2,ooo-foot higher elevation of Florida during 
the ice age (460), an elevation that would mean a very differ- 
ent distribution of land in the Caribbean during the period. 

In two different ways this evidence agrees with our dis- 
placement theory. First, as the direction of the movement of 
the North Atlantic region would hypothetically have been 
equatorward, some subsidence of the ocean basin was log- 



220 EARTH S SHIFTING CRUST 

ically to be expected. Then, as the western side of the At- 
lantic was closer to the meridian of maximum displacement, 
it would have been displaced through more degrees of lati- 
tude, and in consequence there should have been greater 
subsidence on the American side of the ocean. Our theory 
implies that the Hudson Bay region was moved southward 
about 2,000 miles, while at the same time the southward 
movement of France amounted to no more than five hun- 
dred. The ratio of these distances is about four to one, and 
this is very close to the estimated subsidence on the western 
side of the Atlantic, of about 1,000 feet, as compared to that 
on the eastern side, of less than 300. 

From the other side of the globe comes equally impressive 
evidence. Wallace argued for a subsidence of at least 600 feet 
of the coastlines of Southeast Asia and Indonesia at the end of 
the Pleistocene. These areas lie close to the same meridian 
of maximum displacement, the goth meridian, which runs 
through Labrador, and accordingly they should have been 
displaced the same distance as eastern North America, and 
the resulting subsidence should have been of the same order. 
The Philippines are thought to have become separated from 
Asia only some 10,000 years ago; the separation of New 
Guinea from Australia and of Java from Sumatra may have 
been even more recent. Again, the subsidence may have con- 
siderably exceeded 600 feet, which Wallace gives as a mini- 
mum (444:24-25). Needless to say, a rise of the sea level of 
this extent cannot be explained as the result of melting of 
glaciers. 

I have already mentioned the fact that some geophysicists 
seriously doubt that the rise of the land around the former 
glaciated tracts since the end of the ice age is due to isostatic 
rebound. It may be more correctly accounted for as a part of 
the aftermath of the last displacement of the crust. We have 
seen that polar areas are, according to the theory, areas re- 
cently moved poleward. Accordingly, they have undergone 
compression and uplift, the major part of the uplift being 
due to the lag in isostatic readjustment of the crust to the 



NORTH AMERICA AT THE POLE 221 

variation o gravity with latitude (Chapter IV). An equator- 
ward movement of such an area would cause extra subsidence 
more than would occur with an area in isostatic equilib- 
rium at the start of the movement. And subsequently, iso- 
static adjustment would re-elevate the area, but not to its 
original, excessive extent. This interpretation of the rebound 
of the glaciated tracts has the advantage that it can reconcile 
the facts there with the point of view expressed by Gilluly, 
and with the data from other parts of the world that so 
greatly puzzled Daly. 

While there is no evidence that the sea level rose all over 
the world and to the same extent everywhere at the end of 
the ice age, there is a good deal of evidence that it has fallen 
somewhat since. One specialist in this field, Anderson, re- 
ported evidence of a fall of sea level amounting to between 
100 and 140 feet, and extending over a vast area. He made a 
point of emphasizing that this could not be explained by 
the postglacial isostatic rebound of the formerly glaciated 
tracts of North America and Scandinavia. He is thoroughly 
puzzled by what seems to him an inexplicable fact: 

. . . what was the cause of a fall in sea-level at a time when it 
should have been rising owing to the melting of the ice? (4:493). 

This fall of sea level is a matter of very great interest. I 
have already suggested that down to the disappearance of the 
glaciers in the Northern Hemisphere, the melt water from 
them may have pretty well balanced the growth of ice in 
Antarctica, so that there was no important change of sea level. 
With the disappearance of those northern ice sheets, how- 
ever, the situation changed. There was now no longer a 
supply of melt water to balance the withdrawal of water to 
be locked up in the form of snow in Antarctica; consequently 
the sea level had to fall. Even the magnitude of the fall is in 
agreement, if we suppose that by about 10,000 years ago, 
when the northern icecaps dwindled away, the Antarctic 
icecap was half grown. For it is estimated that if the whole 
amount of ice now in Antarctica were suddenly melted, it 



EARTH'S SHIFTING CRUST 

would suffice to raise the sea level between 200 and 300 feet. 
Half of it, therefore, would account for the amount of the 
fall in sea level noted by Anderson. 

There is a widespread impression that the sea level is now 
rising all over the world, but this impression seems to be mis- 
taken. It is natural, considering the widely publicized opin- 
ion that all present-day icecaps are in retreat, that people 
should rush to interpret a relative rise of the sea level at a 
few localities as indications of a general rise, caused by the 
assumed current melting of ice in both hemispheres. An 
examination of the data on which this claim is based shows, 
however, that the evidence is quite insufficient. I recently 
made an inquiry of the United States Coast and Geodetic 
Survey regarding this matter and received in reply a com- 
munication from Dr. H. E. Finnegan, Chief of the Division 
of Tides and Currents, in which he stated: 

. . . Long period tide records from control stations maintained 
by the Coast and Geodetic Survey show that there has been a rela- 
tive rise of sea-level along each of the coasts of the United States. 
The rate of rise varies somewhat with the length of series and dif- 
ferent regions. During the past 20 years the relative rise of sea-level 
along our East Coast has been at the rate of two hundredths of 
a foot per year. On our Pacific Coast the rate has been somewhat 
less. 

In Alaska, the tide records for Ketchikan show no definite change 
in sea-level. At certain places farther north, however, the records 
indicate a relative fall of sea-level. . . . (152). 

This can, I think, be regarded as a summary of the facts 
presently known on this subject. It is plain that it does not 
add up to any universal rise of the sea level. Not only is no 
such rise indicated; exactly the opposite is implied by the 
facts. The facts show that different parts of the United States 
are subsiding at different rates, that Alaska is not subsiding 
at all, and that places farther north are actually rising. What 
reason is there to bring the sea into it? A "eustatic" change in 
sea level is not indicated by these facts, but differential move- 
ments of parts of the continent are. Moreover, the data come 



NORTH AMERICA AT THE POLE 22J 

from a very small part of the earth's surface. Equally careful 
measurements along all the coasts of all the continents would 
be necessary to establish the fact of a general rise in sea level. 
They could as easily establish that the sea level is falling. 

Additional evidences of the fall of the sea level in post- 
glacial times are provided by Halle, for the Falkland Islands 
(196), by Pollock, for Hawaii (34ga), and by Sayles, for Ber- 
muda (366a). Umbgrove, basing his statement on quite other 
sources, concludes that "the sea-level has fallen over the 
whole world in comparatively recent times*' (430:69). 

A quite remarkable bit of evidence comes from Greenland. 
There a whale was recently discovered well preserved in the 
permafrost (the permanently frozen ground). It was dated by 
radiocarbon, and found to be 8,500 years old. It was found 
in beach deposits 43.6 feet above the present sea level. The 
highest beach in the area was 1 30 feet above the present sea 
level. It is hard to see how the elevation of this beach could 
be ascribed to isostatic rebound of the crust since the ice age, 
for there has been no lightening of the ice load on the crust 
in Greenland. How, then, is this frozen whale to be inter- 
preted? I think we can accept it as fairly good evidence of a 
general fall of sea level resulting from the withdrawal of 
water from the oceans to feed the growing Antarctic icecap. 

From the Philippines comes additional evidence that in 
those areas where the sea level rose at the end of the North 
American ice age, the rise was of a magnitude that cannot 
be explained on the theory of glacial melt water, but, on the 
contrary, requires the assumption that important changes 
took place in the crust itself. Warren D. Smith has written: 

It must be said that the geological history and structure of the 
Philippines, as studied in recent years by both Dr. Dickerson and 
myself, seem to indicate that the changes since the Pleistocene in 
the Philippines have been profound enough to have caused the 
disruption of land bridges and to have brought about the present 
isolation of its masses by flooding. . . 



We may note that Smith makes no reference to a rise of 
sea level because of the melting of glaciers. The subsidence 



224 EARTH'S SHIFTING CRUST 

of the islands, and their separation from Asia, are attributed 
to deformation of the earth's crust itself. Moreover, it is un- 
likely that Smith had any conception of how recently these 
events occurred. He probably thought of the Pleistocene (and 
the ice age) as ending 20,000 or 30,000 years ago. Conse- 
quently, the structural changes in the crust that he discusses 
seem to have occurred at a rate which, like the unwarping 
of the crust in North America discussed by Antevs, is in- 
consistent with the speeds of geological change normally 
considered by geologists. There appears to be no rational 
explanation for such an acceleration of the tempo of geolog- 
ical change, except a displacement of the crust. 

There is another important problem connected with the 
changes in sea level. It seems that many of them occurred in 
an abrupt fashion, so suddenly that the continuous cutting 
of the coastline by the sea was unable to keep up with the 
vertical movement of the land. Brooks refers to numerous 
strandlines at elevations of about 90, 126, and 180 feet above 
the present sea level, which may be traced over considerable 
areas (52:491). It seems reasonable that if the rise of the land 
in these localities (or the general fall of the sea) was gradual, 
the erosive action of the sea would have been able to keep 
extending the beach downward continuously. We would 
then have a continuous beach formation extending from 180 
feet above the present sea level, down to the present sea 
margin. We have, on the contrary, a series of completely 
distinct elevated beaches. It would seem that the changes in 
elevation were comparatively rapid. 

There is a possibility that this phenomenon is connected 
with the irregularities of the process of crust displacement 
referred to above. If the interstadials and the repeated re- 
advances of the glaciers during the North American ice age 
resulted from the process I have described, the same process 
of storage and sudden release of stresses in the moving crust 
could easily account for abrupt changes in the elevation of 
sections of the crust. I am not suggesting that they occurred 
in periods of a few days or hours. The facts would be satisfied 



NORTH AMERICA AT THE POLE 225 

by the assumption that they occurred in periods of the order 
of a few centuries. But it is clear that these beaches cannot be 
accounted for by a theory of postglacial upward adjustment, 
for there is no reason why this adjustment should have taken 
place in jumps. It would have been, by its nature, a gradual 
and even process. 



6. Darwin's Rising Beachline in South America 

A singularly impressive piece of evidence for a recent dis- 
placement of the crust may be found in the journal of 
Charles Darwin. Sir Archibald Geikie summarized Darwin's 
findings thus: 

On the west coast of South America, lines of raised terraces con- 
taining recent shells have been traced by Darwin as proofs of a great 
upheaval of that part of the globe in modern geological time. The 
terraces are not quite horizontal but rise to the south. On the frontier 
of Bolivia they occur from 60 to 80 feet above the existing sea-level, 
but nearer the higher mass of the Chilean Andes they are found at 
one thousand, and near Valparaiso at 1300 feet. That some of these 
ancient sea margins belong to the human period was shown by Mr. 
Darwin's discovery of shells with bones of birds, ears of maize, plaited 
reeds and cotton thread, in some of the terraces opposite Callao 
at a height of 85 feet. Raised beaches occur in New Zealand and indi- 
cate a greater change of level in the southern than in the northern 
end of the country. . . . (170:288). 

If we attempt, by analyzing this evidence in accordance 
with the assumptions of the displacement theory, to recon- 
struct the course of events, we reach the following conclu- 
sions: Since the evidence of human occupation is found at an 
elevation of 85 feet, it seems reasonable to suppose that a fall 
of the sea level of that extent may have occurred within his- 
torical times. On the other hand, the continuously rising 
strandline down the coast to Valparaiso, continued in New 
Zealand, indicates a tilting of the earth's crust, involving. 
South America and New Zealand, but not involving a general 
change in the sea level. The magnitude of the upheaval sug- 



226 EARTH'S SHIFTING CRUST 

gests that it may have occurred earlier than the 85-foot gen- 
eral fall in sea level, and may have required much more time. 
The 85-foot fall in the general sea level we may explain as 
the result of the withdrawal of water to Antarctica. The up 
tilting of the continent may be seen as the result of its pole- 
ward displacement. 

The effect postulated by Gutenberg, to account for uplift 
of areas displaced poleward, cannot account for the tilting, 
but another effect may. This is the increasing compression 
of the poleward-moving sector as the result of the progressive 
shortening of the radius and circumference of the earth in 
the higher latitudes. The compressions resulting from this 
have been discussed. They result inevitably from the increas- 
ing arc of the surface and the increasing convergence of the 
meridians. 



VIII : THE GREAT EXTINCTIONS 



When this theory was first presented to a group of scientists 
at the American Museum of Natural History, on January 27, 
1955, Professor Walter H. Bucher, former President of the 
Geological Society of America, made an interesting observa- 
tion. I had presented evidence to support the contention that 
North America had been displaced southward and Antarctica 
had been moved farther into the Antarctic Circle by the 
movement of the crust at the end of the ice age. Professor 
Bucher pointed out that, if this were so, there must have 
been an equal movement of the crust northward on the op- 
posite side of the earth. He asked me whether there was evi- 
dence of this. I said I thought there was. I am presenting the 
evidence here. 



7. The Extinction of the Mammoths 

The closing millennia of the ice age saw an enormous mortal- 
ity of animals in many parts of the world. Hibben estimated 
that as many as 40,000,000 animals died in North America 
alone (212:168). Many species of animals became extinct, in- 
cluding mammoths, mastodons, giant beaver, sabertooth cats, 
giant sloths, woolly rhinoceroses. Camels and horses appar- 
ently became extinct in North America then or shortly after- 
wards, although one authority believes a variety of Pleistocene 
horse has survived in Haiti (365). The paleontologist Scott is 
enormously puzzled both by the great climatic revolution 
and by its effects: 

The extraordinary and inexplicable climatic revolutions had a 
profound effect upon animal life, and occasioned or at least ac- 
companied, the great extinctions, which, at the end of the Pleistocene, 



228 EARTH'S SHIFTING CRUST 

decimated the mammals over three-fifths of the earth's land sur- 
face (37^75)' 

No one has been able to explain these widespread extinc- 
tions. I shall attempt to explain them as consequences of the 
last displacement of the crust, but, since the extinctions took 
place both in North America and in Asia that is, both in the 
area presumably moved southward and in the area presum- 
ably moved northward, I shall concentrate first on Asia. 
There we shall find no difficulty in producing evidence to 
show that the climate of eastern Siberia grew colder as North 
America grew warmer, just as the theory requires. 

Among all the animals that became extinct in Asia, the 
mammoth has been the most studied. This is because of its 
size; because of the great range of its distribution, all the 
way from the New Siberian Islands in the Arctic Ocean, 
across Siberia and Europe, to North America; because pic- 
tures of it drawn by primitive man have been found in the 
caves of southern France and Spain; but most of all, perhaps, 
because well-preserved bodies of mammoths have been found 
frozen in the mud of Siberia and Alaska. Ivory from these 
frozen remains has provided a supply for the ivory trade of 
China and Central Europe since ancient times. 

A study of the reports on the frozen mammoths reveals 
some very remarkable facts. In the first place, they increase 
in numbers the farther north one goes, and are most numer- 
ous in the New Siberian Islands, which lie between the Arc- 
tic coast of Siberia and the pole. Secondly, they are accom- 
panied by many other kinds of animals. Thirdly, although 
ivory is easily ruined by exposure to the weather, uncounted 
thousands of pairs of tusks have been preserved in perfect 
condition for the ivory trade. A fourth point is that the 
bodies of many mammoths and a few other animals have 
been preserved so perfectly (in the frozen ground) as to be 
edible today. Finally, astonishing as it may seem, it is not 
true that the mammoth was adapted to a very cold climate. 
I shall first take up this question of the mammoth's alleged 
adaptation to cold. 



THE GREAT EXTINCTIONS 229 

2. The Mammoth's Adaptation to Cold 

It has long been taken for granted, without really careful 
consideration, that the mammoth was an Arctic animal. The 
opinion has been based on the mammoth's thick skin, on 
its hairy coat, and on the deposit of fat usually found under 
the skin. Yet it can be shown that none of these features 
mean any special adaptation to cold. 

To begin with the skin and the hair, we have a clear 
presentation of the facts by the French zoologist and derma- 
tologist H. Neuville. His report was published as long ago 
as 1919 (325). He performed a comparative microscopic study 
of sections of the skin of a mammoth and that of an Indian 
elephant, and showed that they were identical in thickness 
and in structure. They were not merely similar: they were 
exactly the same. Then, he showed that the lack of oil glands 
in the skin of the mammoth made the hair less resistant to 
cold and damp than the hair of the average mammal. In 
other words, the hair and fur showed a negative adaptation 
to cold. It turns out that the common, ordinary sheep is 
better adapted to Arctic conditions: 

We have . . . two animals very nearly related zoologically, the 
mammoth and the elephant, one of which lived in severe climates 
while the other is now confined to certain parts of the torrid zone. 
The mammoth, it is said, was protected from the cold by its fur 
and by the thickness of its dermis. But the dermis, as I have said, and 
as the illustrations prove, is identical in the two instances; if 
would therefore be hard to attribute a specially adaptive function 
to the skin of the mammoth. The fur, much more dense, it is true, 
on the mammoths than on any of the living elephants, nevertheless 
is present only in a very special condition which is fundamentally 
identical in all of these animals. Let us examine the consequences 
of this special condition, consisting, I may repeat, in the absence of 
cutaneous glands. The physiological function of these glands is very 
important. [Neuville's footnote here: It is merely necessary to men- 
tion that according to the opinion now accepted, that of Unna, 
the effect of the sebum is to lubricate the fur, thus protecting it 
against disintegration, and that of the sweat is to soak the epidermis 



230 EARTH'S SHIFTING CRUST 

with an oily liquid, protecting it also against desiccation and dis- 
integration ... the absence of the glandular secretions puts the 
skin in a condition of less resistance well known in dermatology. 
It is superfluous to recall that the sebaceous impregnation gives the 
fur in general its isolating properties and imparts to each of its 
elements, the hairs, its impermeability, thanks to which they resist 
with a well-known strength all disintegrating agents, and notably 
those which are atmospheric. Everyone knows to what degree the 
presence of grease produced by the sebaceous glands renders wool 
resistant and isolating, and to what degree the total lack of this fatty 
matter lessens the value of woolen goods. . . .] (325:331-33). 

Neuville, then, points out in the foregoing passage both 
that the mammoth lacks sebaceous glands and that the oil 
from these glands is an important factor in the protection of 
an animal against cold. It is probable, also, that protection 
from damp is more important than protection from low tem- 
perature. Oil in the hair must certainly impede the penetra- 
tion of damp. The hair of the mammoth, deprived of oil, 
would seem to offer poor protection against the dampness 
of an Arctic blizzard. Sanderson has pointed out that thick 
fur by itself means nothing: a lot of animals of the equatorial 
jungles, such as tigers, have a thick fur (365). Fur by itself 
is not a feature of adaptation to cold, and fur without oil, as 
Neuville points out so lucidly, is, if anything, a feature of 
adaptation to warmth, not cold. 

The question of the importance of oily secretions from the 
skin for the effectiveness of resistance of fur or hair to cold 
and damp is, however, highly involved. Very many inquir- 
ies directed to specialists in universities, medical schools, 
and research institutes over a period of more than five years 
failed to elicit sufficiently clear and definite answers until, 
finally, Dr. Thomas S. Argyris, Professor of Zoology at 
Brown University, referred me to the Headquarters Research 
and Development Command of the United States Army. 
This agency, in turn, very kindly referred me to the British 
Wool Industries Research Association. I addressed an in- 
quiry to them, regarding the effects of natural oil secre- 



THE GREAT EXTINCTIONS 231 

tions from the skin on the preservation of wool. They replied 
in general confirmation of Neuville: 

. . . Those interested in wool assume that the function of the 
wool wax is to protect the wool fibres from the weather and to 
maintain the animal in a dry and warm condition. Arguments in 
this direction are of course mainly speculative. We do know, however, 
that shorn wool in its natural state can be stored and transported 
without entanglement (or felting) of the fibres, while scoured wool 
becomes entangled so that, during subsequent processing, fibre 
breakage at the card is significantly increased. It seems reasonable, 
therefore, to assume that the wool wax is responsible not only for 
conferring protection against the weather but also for the mainte- 
nance of the fleece in an orderly and hence more efficacious state 
(458). 

It appears that there has been no scientific study of the pre- 
cise points at issue here; no one has measured in any scien- 
tific way the quantitative effect of oily secretions in keeping 
heat in or moisture out. Despite this fact, however, we are 
at least justified, on the basis of the facts cited above, in re- 
jecting the claims advanced for the hair of the mammoth as 
an adaptive feature to a very cold climate. 

Neuville goes on to destroy one or two other arguments 
in favor of the mammoth's adaptation to cold: 

... It has been thought that the reduction of the ears, thick and 
very small relatively to those of the existing elephants, might be so 
understood in this sense; such large and thin ears as those of the 
elephants would probably be very sensitive to the action of cold. 
But it has also been suggested that the fattiness and peculiar form 
of the tail of the mammoth was an adaptive character of the same 
kind; however, it is to the fat rumped sheep, animals of the hot 
regions, whose range extends to the center of Africa, that we must 
go for an analogue to the last character. 

It is therefore, only thanks to entirely superficial comparisons 
which do not stand a somewhat detailed analysis, that it has been 
possible to regard the mammoth as adapted to the cold. On account 
of the peculiar character of the pelage the animal was, on the con- 
trary, at a disadvantage in this respect (325:331-33). 

There remains the question of the layer of fat, about 
three inches thick, which is found under the skin of the 



EARTH'S SHIFTING CRUST 

mammoth. This fat is thought to have provided insulation 
against the bitter cold of the Siberian winter. 

The best opinion of physiologists is opposed to the view 
that the storage of fat by animals is a measure of self-pro- 
tection against cold. The consensus is, on the contrary, that 
large fat accumulation testifies chiefly to ample food supply, 
obtainable without much effort, as, indeed, is the case with 
human beings. Physiologists agree that resistance to cold is 
mainly a question of the metabolic rate, rather than of in- 
sulation by fat. Since the length of capillaries in a cubic 
inch of fat is less than the length of capillaries in a cubic 
inch of muscle, blood circulation would be better in a thin 
animal. We might ask the question, Which would be more 
likely to survive through a Siberian winter, a man burdened 
with fifty or a hundred pounds of surplus fat or a man of 
normal build who was all solid muscle, assuming that winter 
conditions would mean a hard struggle to obtain food? Dr. 
Charles P. Lyman, Professor of Zoology at Harvard, re- 
marked, regarding this question of fat: 

It is true that many animals become obese before the winter sets 
in, but for the most part it seems likely that they become obese 
because they have an ample food supply in the fall, rather than 
that they are stimulated by cold to lay down a supply of fat. Cold 
will ordinarily increase the metabolic rate of any animal which means 
that it burns up more fuel in order to maintain its ordinary weight, 
to say nothing of adding weight in the form of fat. The amount of 
muscular activity in the daily life of either type of elephant is 
certainly just as important as the stimulus of cold as far as laying 
down a supply of fat is concerned (284). 

This statement suggests that there is no basis for the as- 
sumption that the fat of the mammoths adapted them to an 
Arctic climate. On the other hand, it is quite true that the 
storage of fat in the fall may help animals to get through 
the winter when food is scarce. The winter does not, how- 
ever, have to be an Arctic winter. A white* such as we have 
in temperate climates is quite cold enough to cut the avail- 
able food supply for herbivorous animals. It seems that under 



THE GREAT EXTINCTIONS 

favorable circumstances even the African and Indian ele- 
phants accumulate quite a lot of fat. F. G. Benedict, in his 
comprehensive work on the physiology of the elephant, con- 
siders it a fatty animal (27). 

The resemblances between the mammoth and the Indian 
elephant extend further than the identity of their skins in 
thickness and structure, and the fact that they were both fatty 
animals. Bell suggests that they were only two varieties of the 
same species: 

Falconer insists on the importance of the fact that throughout the 
whole geological history of each species of elephant there is a great 
persistence in the structure and mode of growth of each of the 
teeth, and that this is the best single character by which to distinguish 
the species from one another. He finds, after a critical examination 
of a great number of specimens, that in the mammoth each of the 
molars is subject to the same history and same variation as the cor- 
responding molar in the living Indian elephant (25). 

It is clear that the similarities in the life histories of each 
of the teeth of these two animals are more important than the 
differences in the shapes of the teeth, which were such as 
might easily occur in two varieties of the same species. It 
cannot be denied that two varieties of the same species may 
be adapted to different climates, but it must be conceded 
that the adaptation of two varieties of the same species, one 
to tropical jungles and the other to Arctic conditions, is 
against the probabilities. 



3. The Present Climate of Siberia 

, are a r 
The people who lay the greatest st^ rudde** 16 adaptation of 

the mammoth to cold ignore the ouier a^mals that lived 
with the mammoths. Yet we know that along with the mil- 
lions of mammoths, the northern Siberian plains also sup- 
ported vast numbers of rhinoceroses, antelope, horses, bison, 
and other herbivorous creatures, while a variety of carnivores, 
including the sabertooth cat, preyed upon them. What good 



EARTH'S SHIFTING CRUST 

does it do to argue that the mammoth was adapted to cold 
when it is impossible to use the argument in the case of sev- 
eral of the other animals? 

Like the mammoths, these other animals ranged to the far 
north, to the extreme north of Siberia, to the shores of the 
Arctic Ocean, and yet farther north to the Lyakhov and New 
Siberian Islands, only a very short distance from the pole. 
It has been claimed that all the remains on the islands may 
have been washed there from the mouths of the Siberian 
rivers by spring floods; I shall consider this suggestion a little 
later. 

So far as the present climate of Siberia itself is concerned, 
Nordenskjold made the following observations of monthly 
averages of daily Centigrade temperatures during the year 
along the Lena River (334): 

January 48.9 July 154 

February 47.2 August 11.9 

March 33.9 September 2.3 

April 14 October 13.9 

May 0.14 November 39.1 

June 13.4 December 45.1 

The average for the whole year was 16.7. Since zero in the 
Centigrade scale is the freezing point of water, it will be 
seen that only one or two months in the year are reasonably 
^ee from frost. Even so, there must be frequent frosts in 
'jr . notwithstanding occasional high midday temperatures. 
No (3!u ai H was knwledge of these conditions that caused 
the great fc^ jf modern geology, Sir Charles Lyell, to 

remark that it -> s t$ tha tofl^ J* be impossible for herds of 
mammoths and t.the m^ .v 3 * subsist, throughout the year, 
even in the southern part: of Siberia. . . . 

If this is the case with Siberia, what are we to think when 
we contemplate the New Siberian Islands? There the re- 
mains of mammoths and other animals are most numerous 
of all. There Baron Toll found remains of a sabertooth cat, 
and a fruit tree that had been ninety feet high when it was 



THE GREAT EXTINCTIONS 

standing. The tree was very perfectly preserved in the perma- 
frost, with its roots and seeds (113:151). Toll claimed that 
green leaves and ripe fruit still clung to its branches. Yet, at 
the present time, the only representative of tree vegetation 
on the islands is a willow that grows one inch high. 

Now let us return to the question of whether all these re- 
mains were floated out to the islands on spring floods. Let us 
begin with a backward view at the history of these islands. 
Saks, Belov, and Lapina point to evidence that there were 
luxuriant forests growing on the New Siberian Islands in 
Miocene and perhaps Pliocene times (364). At the beginning 
of the Pleistocene the islands were connected with the main- 
land, and the mammoths ranged over them. In the opinion 
of these writers the vast numbers of mammoth remains on 
Great Lyakhov Island indicate that they took refuge on the 
island when the land was sinking (364:4, note). There is no 
evidence that they were washed across the intervening sea. 

The improbabilities in this suggestion of transportation of 
these hundreds of thousands of animal bodies across the 
entire width of the Nordenskjold Sea, for a distance of more 
than 200 miles from the mouth of the Lena River, are simply 
out of all reason. Let us see exactly what is involved. 

First, we should have to explain why the hundreds of thou- 
sands of animals fell into the river. To be sure, they did not 
fall in all at once; nevertheless, they must have had the habit 
of falling into the river in very large numbers, because only 
one body in a very great many could possibly float across 200 
miles of ocean. Of those that floated at all only a few would 
be likely to float in precisely the correct direction to reach 
the islands. Islands, even large ones, are amazingly easy to 
miss even in a boat equipped with a rudder and charts. The 
Lena River has three mouths, one of which points in a direc- 
tion away from the islands. The two other mouths face the 
islands across these 200 miles of ocean. Occasionally, a piece 
of driftwood might float across the intervening sea. Occa- 
sionally, perhaps, an animal if for some reason it did not 
happen to sink, if it were not eaten by fishes might be 



236 EARTH'S SHIFTING CRUST 

washed up on the shore of one of the islands. It seems proba- 
ble that only an incredibly powerful current could transport 
the body of a mammoth across 200 miles of ocean. 

But let us suppose that somehow the animals are trans- 
ported across the ocean. What then? The greatest of the New 
Siberian Islands is about 150 miles long and about half as 
wide. Not one single account of the explorations on these 
islands has mentioned that the animal remains are found 
only along the beaches. They are obviously found also in the 
interior. Are we to suppose that the floods of the Lena River 
were so immense that they could inundate the New Siberian 
Islands, 200 miles at sea? It is safe to say that all the rivers 
of Europe and Asia put together, at full flood, would fail to 
raise the ocean level 200 miles off the coast by more than a 
few inches at most. 

But, again, let us suppose that the remains were merely 
washed to the present coasts, and not into the interior. How 
then were they preserved? How were hundreds of thousands 
of mammoths placed above high-water mark? Storms, no 
doubt, but whatever storms can wash up, other storms can 
wash away. No accumulation of anything occurs along the 
coasts because of storms. All that storms can do is to destroy; 
they can grind up and destroy anything. And they would 
have ground up and destroyed all the bodies, including, of 
course, the go-foot fruit tree with its branches, roots, seeds, 
green leaves, and ripe fruit. 

I think it is plain that the only reason suggestions of this 
kind are advanced is that there is need to support some 
theory that has been developed to explain some other part of 
the evidence, some local problem. Moreover, there is need, 
always need, to discredit the evidence that argues for drastic 
climatic changes. 

Naturally, the knowledge that the Arctic islands, though 
they are now in polar darkness much of the year, were in 
very recent geologic times able to grow the flourishing 
forests of a temperate climate, eliminates any need to in- 
sist that they were always as cold as they are today. Thus, 



THE GREAT EXTINCTIONS 237 

it is not a question at all of whether the climate grew 
colder, but merely a question of when the change oc- 
curred. I have already discussed the evidence showing that 
it occurred (for the last time, anyway) when North Amer- 
ica moved southward from the pole. 

Campbell has contributed a suggestion with regard to 
the alleged floating of hundreds of thousands of bodies 
across the Nordenskjold Sea. He notes that bodies ordinarily 
float because of gas produced by decomposition. Decomposi- 
tion is at a minimum in very cold water, and therefore bodies 
ordinarily do not float in very cold water. As an example of 
this he points to a peculiarity of Lake Superior. The waters 
of this lake are very cold. This may be because they are sup- 
plied, as some people think, by underground springs from 
the Rocky Mountains, far away. And there is an old saying 
in the lake region that "Lake Superior never gives up its 
dead." But the Arctic Ocean is as cold as the springs fed by 
the glaciers of the Rockies. The water of the Lena would 
not be warm even in midsummer, but during the spring 
floods when the Lena would be swollen with the melt water 
of the winter snows the water at such times would be frigid, 
and the bodies of animals drowned in it would not decom- 
pose, nor would they float. They would tend to sink, instead, 
into the nearest hole, and never come to the surface. 



4. A Sudden Change of Climate? 

We may reasonably conclude that the climate of Siberia 
changed at the end of the Pleistocene, and that it grew colder. 
Our problem is to discover what process of change was in- 
volved. On the one hand, our theory of displacement of the 
crust involves a considerable period of time, and a gradual 
movement; on the other hand, the discovery of complete 
bodies of mammoths and other animals in Siberia, so well 
preserved in the frozen ground as to be in some cases still 
edible, seems to argue a cataclysmic change. 



238 EARTH'S SHIFTING CRUST 

To those who, in the past, have argued for a very sudden 
catastrophe, the specialists in the field have offered opposing 
theories to explain the preservation of the bodies. One of 
these was that as the mammoths walked over the frozen 
ground, over the snow fields, they may have fallen into pits 
or crevasses and been swallowed up and permanently frozen. 
Or, again, they might either have broken through river ice 
and been drowned, or they might have got bogged while 
feeding along the banks. 

There is no doubt that a certain number of animals could 
have been put into the frozen ground in just the manner sug- 
gested above. That this is the explanation for the preserva- 
tion of the mammoths' bodies generally, however, is unlikely 
for a number of reasons. 

It is not generally realized, in the first place, that it is not 
merely a matter of the accidental preservation of eighty-odd 
mammoths and half a dozen rhinoceroses that have been 
found in the permafrost. These few could perhaps be ac- 
counted for by individual accidents, provided, of course, that 
we agreed that the animals concerned were Arctic animals. 
The sudden freezing and consequent preservation of the 
flesh of these animals might be thus explained. But there is 
another factor of great importance, which has been con- 
sistently neglected. It has been overlooked that meat is not 
the only thing that has to be frozen quickly in order to be 
preserved. The same is true of ivory. Ivory, it appears, spoils 
very quickly when it dries out. 

Tens of thousands of skeletons and individual bones of 
many kinds of animals have been discovered in the perma- 
frost. Among them have been found the enormous numbers 
of mammoths' tusks already mentioned. To be of any use 
for carving, tusks must come either from freshly killed ani- 
mals or have been frozen very quickly after the deaths of the 
animals, and kept frozen. Ivory experts testify that if tusks 
are exposed to the weather they dry out, lose their animal 
matter, and become useless for carving (280:361-66). 

According to Lydekker, about 20,000 pairs of tusks, in 



THE GREAT EXTINCTIONS 239 

perfect condition, were exported for the ivory trade in the 
few decades preceding 1899, yet even now there is no end 
in sight. According to Digby, about a quarter of all the mam- 
moth tusks found in Siberia are in good enough condition 
for ivory turning (113:177). This means that hundreds of 
thousands of individuals, not merely eighty or so, must have 
been frozen immediately after death, and remained frozen. 
Obviously, it is unreasonable to attempt to account for these 
hundreds of thousands of individuals by the assumption of 
such rare individual accidents as have been suggested above. 
Some powerful general force was certainly at work. Lydekker 
gives many hints of the nature of this force in the following 
passage: 

... In many instances, as is well known, entire carcasses of the 
mammoth have been found thus buried, with the hair, skin and flesh 
as fresh as in frozen New Zealand sheep in the hold of a steamer. 
And sleigh dogs, as well as Yakuts themselves, have often made a 
hearty meal on mammoth flesh thousands of years old. In instances 
like these it is evident that mammoths must have been buried and 
frozen almost immediately after death; but as the majority of the 
tusks appear to be met with in an isolated condition, often heaped 
one atop another, it would seem that the carcasses were often broken 
up by being carried down the rivers before their final entombment. 
Even then, however, the burial, or at least the freezing, must have 
taken place comparatively quickly as exposure in their ordinary con- 
dition would speedily deteriorate the quality of the ivory (280:363). 

He continues: 

How the mammoths were enabled to exist in a region where their 
remains became so speedily frozen, and how such vast quantities of 
them became accumulated at certain spots, are questions that do not 
at present seem capable of being satisfactorily answered; and their 
discussion would accordingly be useless. . . . (280:363). 

Lydekker was not alone in feeling the futility of considering 
these mysterious facts. For many years, in this field as in 
others, there has been a tendency to put away questions that 
could not be answered. However, we shall return to his state- 
ment. I shall try to show later on how all the details of the 
phenomena he describes can be made understandable. For 



240 EARTH'S SHIFTING CRUST 

the moment, I would like to point out simply that some sort 
of abrupt climatic change is required. This conclusion is re- 
inforced by the results of recent research in the frozen foods 
industry. This has produced evidence that throws additional 
doubt on the theory of the preservation of the bodies of 
mammoths by individual accidents. It seems that the preser- 
vation of meat by freezing requires some rather special condi- 
tions. Herbert Harris, in an article on Birdseye in Science 
Digest, writes: 

What Birdseye had proved was that the faster a food can be frozen 
at "deep" temperatures of around minus 40 degrees Fahrenheit, the 
less chance there is of forming the large ice crystals that tear down 
cellular walls and tissues leaving gaps through which escape the 
natural juices, nutriment and flavor (202:3). 

Harris quotes one of Birdseye's engineers as saying: 

. . . take poultry giblets; they can last eight months at 10 below zero, 
but "turn" in four weeks above it. Or lobster. It lasts 24 months at 
10 below but less than twenty days at anything above. . . . (202:5). 

In the light of these statements the description of the 
frozen mammoth flesh given by F. F. Herz is very illumi- 
nating. Quoted by Bassett Digby in his book on the mam- 
moth, Herz said that "the flesh is fibrous and marbled with 
fat." It 'looks as fresh as well frozen beef." And this remark 
is made of flesh known to have been frozen for thousands of 
years! Some people have reported that they have been made 
ill by eating this preserved meat, but occasionally, at least, it 
is really perfectly edible. Thus Mr. Joseph Barnes, former 
correspondent of the New York Herald Tribune, remarked 
on the delicious flavor of some mammoth meat served to him 
at a dinner at the Academy of Sciences in Moscow in the 
i93o's (24). 

What Birdseye proved was that meat to remain in edible 
condition must be kept very coldnot merely frozen, but at 
a temperature far below the freezing point. What the edible 
mammoth steaks proved was that meat had been so kept in 
at least a few cases for perhaps 10,000 to 15,000 years in the 



THE GREAT EXTINCTIONS 241 

Siberian tundra. It is reasonable to suppose that the same 
cause that was responsible for the preservation of the meat 
also preserved the ivory; and therefore that tens or hundreds 
of thousands of animals were killed in the same way. 

How can such low temperatures for the original freeze be 
reconciled with the idea of individual accidents unless at 
least the animals died in the middle of the winter? It is quite 
certain that such temperatures could never have prevailed 
at the surface or in mudholes during "spring freshets." Ripe 
seeds and buttercups, found in the stomach of one of the 
mammoths, to be discussed later, showed that his death took 
place in the middle of the summer. It is obvious that during 
the summer the temperature at the top of the permafrost 
zone was and is 32 F. or o Centigrade, neither more nor 
less, since by definition that is where melting begins. And 
from that point down there would be only a relatively 
gradual fall in the prevailing temperature of the permafrost. 

Even if mammoths died in the winter, it is difficult to see 
how very many of them could have become well enough 
buried to have escaped the warming effects of the thaws of 
thousands of springs and summers, which would have rotted 
both the meat and the ivory, unless there was a change of 
climate. 

The theory that mammoths may have been preserved by 
falls into pits or into rivers encounters further objections. 
Tolmachev, the Russian authority, pointed out that the re- 
mains are often found at high points on the highest points 
of the tundra (422:51). He notes that the bodies are found 
in frozen ground, and not in ice, and that they must have 
been buried in mud before freezing. This presents a serious 
problem because, as he says, 

... As a matter of fact, the swamps and bogs of a moderate climate 
with their treacherous pits, in northern Siberia, owing to the perma- 
nently frozen ground, could exist only in quite exceptional conditions 
(422:57)- 

Ho worth remarked on this same problem: 



242 EARTH'S SHIFTING CRUST 

While it is on the one hand clear that the ground in which the 
bodies are found has been hard frozen since the carcasses were en- 
tombed, it is no less inevitable that when these same carcasses were 
originally entombed, the ground must have been soft and unfrozen. 
You cannot thrust flesh into hard frozen earth without destroying it 



Since Tolmachev can think of no other solution to this 
problem, he finds himself forced to conclude that the mam- 
moths got trapped in mud when feeding on river terraces. 
We have seen that this conflicts seriously with the conditions 
of temperature required for the preservation of the meat, 
whether they were feeding on the terraces during the sum- 
mer, when, presumably, the fresh grass supply would be 
available there, or whether they were shoving aside the heavy 
snowdrifts during the winter to attempt to get at the dead 
grass below. For in either case they would fall into unfrozen 
water, the temperature of which could not be lower than 32 
Fahrenheit. Furthermore, if this is the way it happened, why 
are the animals often found on the highest point of the 
tundra? 

Thus we see that the further we get into this question the 
thornier it becomes. We shall have, for one thing, to face the 
problem of the apparently sudden original freeze. How sud- 
den, indeed, must it have been? How can we account for it 
on the assumption of a comparatively slow displacement of 
the earth's crust? So far as the first question is concerned, 
recent research has contributed interesting new data. 

Research on the mechanics of the freezing process and its 
effects on animal tissues has been carried forward consider- 
ably since the experiments conducted by Birdseye's engi- 
neers. In a recent article in Science, Meryman summarizes 
the recent findings. These are based on extremely thorough 
laboratory research, and they modify, to some extent, the 
Birdseye findings. 

Meryman shows that initial freezing at deep temperatures 
is not required for the preservation of meat. On the contrary, 
such sudden deep freeze may destroy the cells. He remarks, 



THE GREAT EXTINCTIONS 24$ 

"Lovelock considers 5 C. as the lowest temperature to 
which mammalian cells may be slowly frozen and still sur- 
vive." Furthermore, the tissues survive gradual freezing very 
well: 

In most, if not all, soft tissue cells there is no gross membrane rup- 
ture by slow freezing. Even though it is frozen for long periods of 
time, upon thawing the water is reimbibed by the cells, and their 
immediate histological appearance is often indistinguishable from the 
normal. 

It appears that what damages the cells is dehydration, caused 
by the withdrawal of water from them to be incorporated in 
the ice. This process goes on after the initial freezing: 

. . . The principal cause of injury from slow freezing is not the 
physical presence of extracellular ice crystals, but the denaturation 
incurred by the dehydration resulting from the incorporation of all 
free water into ice (304:518-19). 

There are only two known ways, according to Meryman, to 
prevent this damage. First, ". . . the temperature may be 
reduced immediately after freezing to very low, stabilizing 
temperatures." The other way is artificial; it consists of using 
glycerine to bind water in the liquid state, preventing freez- 
ing. 

Meryman shows that once the temperature has fallen to 
a very low point, it must remain at that point if the frozen 
product is to escape serious damage. The reason for this is 
that except at these low temperatures, a recrystallization 
process may take place in ice, in which numerous small 
crystals are combined into large ones. The growth of the 
large crystals may disrupt cells and membranes. He remarks: 

At very low temperatures, recrystallization is relatively slow, and 
equilibrium is approached while the crystals are quite small. At 
temperatures near the melting point, recrystallization is rapid, and 
the crystals may grow to nearly visible size in less than an hour (304: 
518). 

I am reminded, in writing these lines, of my experience in 
truck gardening. In trying to reduce damage from frost, I 



244 EARTH'S SHIFTING CRUST 

often resorted to a method that was effective but mysterious, 
for I could not understand why it worked. I learned that if 
the vegetables got frosted even heavily frostedthey would 
not be seriously damaged if I could manage to get out before 
sunrise and thoroughly hose them off, washing away the 
frost. If, however, the sun should rise before I was finished, 
the unwashed vegetables would be damaged. It would seem, 
according to the explanation given by Meryman, that the 
frost damage was the result of recrystallization of the ice that 
had formed within the vegetable fibers. Small crystals, grow- 
ing into large ones in the hour or so before the sun was up 
far enough to melt them, evidently caused the damage. 

It follows, from this analysis of the mechanics of freezing, 
that the preservation of mammoth meat for thousands of 
years may be accounted for by normal initial freezing, fol- 
lowed by a sharp fall in temperature. Whenever the meat 
was preserved in an edible condition the deep freeze must 
have been uninterrupted; there must have been no thaws 
sufficient to bring the temperature near the freezing point. 

Let us now take a closer look at one of these preserved 
mammoths, and see what it may have to tell us. 



5. The Beresovka Mammoth 

Perhaps the most famous individual mammoth found pre- 
served in the permafrost was the so-called Beresovka mam- 
moth. This mammoth was discovered sticking out of the 
ground not far from the bank of the Beresovka River in 
Siberia about 1901. Word of it reached the capital, St. Peters- 
burg. It so happened that, a long time before, word of 
another mammoth had come to the ears of Tsar Peter the 
Great. With his strong interest in natural science, the Tsar 
had issued a ukase ordering that whenever thereafter another 
mammoth was discovered, an expedition should be sent out 
by his Imperial Academy of Sciences to study it. 

In accordance with this standing order, a group of dis- 



THE GREAT EXTINCTIONS 245 

tinguished academicians entrained at St. Petersburg and pro- 
ceeded to the remote district of Siberia where the creature 
had been reported. When they arrived they found that the 
wolves had chewed off such parts of the mammoth as projected 
aboveground, but most of the carcass was still intact. They 
erected a structure over the body, and built fires so as to thaw 
the ground and permit the removal of the remains. This 
process was hardly agreeable, since, the moment the meat 
began to thaw, the stench became terrific. However, several 
academicians remarked that after a little exposure to the 
stench, they became used to it. They ended by hardly notic- 
ing it. 

Eventually the body of the entire mammoth was removed 
from the ground. The academicians, meantime, made careful 
observations of its original position. They saw evidence that, 
in their opinion, the mammoth had been mired in the mud. 
It looked as if its last struggles had been to get out of the 
mud, and as if it had frozen to death in a half-standing posi- 
tion. Strangely enough, the animal's penis was fully erect. 
Two major bones, a leg bone and the pelvic bone, had been 
broken as if by a fall. There was still some food on the ani- 
mal's tongue, and between his teeth, indicating an abrupt 
interruption of his last meal. The preliminary conclusion sug- 
gested by these facts was that the animal met his death by 
falling into the river. A little later on we shall re-examine 
this conclusion. 

Very special interest attached to the analysis of the contents 
of this animal's stomach. These consisted of about fifty 
pounds of material, largely undigested and remarkably well 
preserved. While the foregoing data were obtained from a 
translation of parts of the report of the academicians, pub- 
lished by the Smithsonian Institution, the section dealing 
with the stomach contents was specially translated for this 
work by my aunt, Mrs. Norman Hapgood. Since there are 
many interesting points essential to an understanding of the 
question, which can be noted only by a reading of the report 
itself, and which do not figure in the published accounts, I 



246 EARTH'S SHIFTING CRUST 

reproduce the stomach analysis by V. N. Sukachev, with 
omission of technical botanical terms where possible, and 
with omission of bibliographical references to Russian, Ger- 
man, and Latin sources, and some shortening of the com- 
ment (410). 

We can definitely establish the following types of plants in the 
food in the stomach and among the teeth of the Beresovka mammoth 
[Latin names are those of the Russian text]: 

a. Alopecurus alpinus sin. The remains of this grass are numerous 
in the contents of the stomach. A significant portion of it consists of 
stems, with occasional remnants of leaves, usually mixed in with other 
vegetable remains. ... All these remains are so little destroyed that 
one is able to establish with exactitude to what species they be- 
long. . . . 

Measurements of the individual parts of these plants, when com- 
pared with the varieties of the existing species, showed that the 
variety contained in the food was more closely related to that now 
found in the forest regions to the south of the tundra than to the 
varieties now found in the tundra. Nevertheless, this is an Arctic 
variety and is widely spread over the Arctic regions, in North America 
and Eurasia. However, in the forested regions it runs far to the south. 

b. Beckmannia eruciformis (L.) Host. The florets of this plant are 
numerous in the contents of the stomach and usually are excellently 
preserved. [The detailed description of the remains (with precise 
measurements in millimeters) shows the species to be the same as that 
of the present day, although a little smaller, which may be the result of 
compaction in the stomach. At the present time the species is widely 
prevalent in Siberia and in the Arctic generally. It grows in flooded 
meadows or marshes. It is also found in North America, the south of 
Europe, and a major part of European Russia (although it has not 
been reported from northern Russia), almost all of Siberia, Japan, 
North China, and Mongolia.] 

c. Agropyrum cristatum (L.) Bess. Remains of this plant are very 
numerous in the contents of the stomach. [They are so well preserved 
that there is no doubt as to the exact species. The individual speci- 
mens are slightly smaller than those of the typical more southern 
variety growing today, but this could be the result of some reduction 
of size because of pressure in the stomach, which is noted in other 
cases.] 

The finding of these plants is of very great interest. Not only are 
they scarcely known anywhere in the Arctic regions, they are even, so 
far as I have been able to discover, very rare also in the Yakutsk dis- 



THE GREAT EXTINCTIONS 247 

trict. . . . Generally speaking the Agropyrum cristatum L. Bess is a 
plant of the plains (steppes) and is widespread in the plains of Dauria. 
. . . The general range of this plant includes southern Europe (in 
European Russia it is adapted to the plains belt), southern Siberia, 
Turkestan, Djungaria, Tian-Shan, and Mongolia. 

Nevertheless, the variety found in the stomach differs slightly from 
both the European and Oriental-Siberian varieties found today. 

d. Hordeum violaceum Boiss. et Huet. [After a detailed anatom- 
ical description of the remains of this plant in the stomach contents, 
the writer continues.] Our specimens are in no particular different 
from the specimens of this species from the Yakutsk, Irkutsk, and 
Transbaikal districts. [The plant is, apparently, no longer found 
along the Lena River, except south of its junction with the Aldan 
River. It is found in dry, grassy areas. It is not found in the Arctic 
regions.] Its northernmost point is apparently Turochansk. . . . Gen- 
erally speaking, in Siberia this plant is a meadow plant and is also 
found in moister places in the plains. 

e. Agrostis sp. ... it does not appear possible to identify the 
species positively. [Apparently, no plant precisely similar is known at 
the present day. Thus it may represent an extinct form.] 

f. Gramina gen. et sp. A grass, but preservation is not good 
enough to allow any more precise identification. 

g. Carex lagopina Wahlenb. The remains of this sedge are numer- 
ous in the contents of the stomach. [The specimens exactly resemble 
varieties growing today. The measurements show no reduction in 
size. Its range extends to the shores of the Arctic Ocean. It is found 
in mountainous regions, including the Carpathians, Alps, and Pyre- 
nees. It is also found in the peat bogs of western Prussia, in Siberia 
as far south as Transbaikalia and Kamchatka, in eastern India, North 
America, and the southern island of New Zealand.] 

h. [Omitted apparently a numbering error in the text.] 
i. Ranunculus acris L. [The specimens in the stomach did not 
permit identification of the precise variety of this buttercup, though 
pods equally large are occasionally found.] The general range of this 
plant is very great. It includes all Europe and Siberia, it stretches to 
the extreme north, spreads to China, Japan, Mongolia, and North 
America. However, over this area this species very much deteriorates 
into many varieties which are considered by some to be independent 
species. [This plant grows in rather dry places. It is not at present 
found growing together with the Beckmannia Eruciformis, although 
it is found with it in the stomach.] 

j. Oxytropis sordida (Willd) Trantv. In the contents of the stom- 
ach were found several fragments of these beans. ... In the frag- 



248 EARTH'S SHIFTING CRUST 

ments taken from the teeth there were found eight whole bean pods 
in a very good state of preservation; they even in places retained five 
beans. . . . [The plant is now found in Arctic and sub-Arctic regions, 
but also in the northern forests. It grows in rather dry places.] 

In addition to the nine species mentioned above, and de- 
scribed in the report, with numerous measurements, the 
author reports that two kinds of mosses were identified in 
the stomach contents by Professor Broterus, of Finland. 
There were five sprigs of Hypnum fluitans (Dill.) L. and one 
sprig of Aulacomnium turgidum (Wahlenb.) Schwaegr. The 
first is common in Siberia north of the Gist parallel of latitude 
and to the marshlands of northern Europe. Both of them "be- 
long to species widely distributed over both the wooded and 
the tundra regions." 

The report states, further, that another scientist, F. F. Herz, 
brought back several fragments of woody substances and bark 
from beneath the mammoth, and of the species of vegetation 
among which it was lying. Very surprisingly, these were 
found to differ in a marked degree from the contents of the 
stomach. A larch (Larix sp.) was finally identified, but the 
genus only, not the species. 

Another tree identified in a general way was Betula Alba 
L.S.I., but the exact species could not be determined. The 
same was true of a third tree, Alnus sp. "All three of these 
kinds grow at present in the Kolyma River basin, and along 
the Beresovka, as they are widespread in general from the 
northern limits of the wooded belt to the southern plains." 

The general conclusions reached in the report are as 
follows. 

a. The remains of plants in the mammoth's mouth, among 
its teeth, were the same as the stomach contents, and repre- 
sented food the mammoth had not yet swallowed when it was 
killed. 

b. The food consisted preponderantly of grasses and sedge. 
"No remains at all of conifers were found." Therefore, "one 
may conclude that the Beresovka mammoth did not, as was 
previously thought, feed mainly on coniferous vegetation but 



THE GREAT EXTINCTIONS 24Q 

mainly on meadow grasses." Evidently he wandered into 
low, moist places, and also into higher, drier places such as 
are now found in the same region. 

c. "The finding of the wood remains under the mammoth, 
and even the cliff itself where the mammoth was lying, sug- 
gest that he was not feeding in the place where he died. The 
majority of the vegetation in his food did not grow along 
cliffs or in conjunction with species of trees." 

d. The discovery of the ripe fruits of sedges, grasses, and 
other plants suggests that "the mammoth died during the 
second half of July or the beginning of August." 

The report concludes that while the contents of the stom- 
ach do not prove that the climate was warmer in the days of 
the mammoth than it is today, neither do they exclude the 
possibility that it was warmer. However, the climate was, in 
any case, not much warmer. The evidence provides no clew 
to the cause of the extinction of the mammoths. 



6. The Interpretation of the Report 

On the assumption that we are dealing with a displacement 
of the earth's crust beginning about 18,000 years ago and 
ending about 8,000 years ago, possibly punctuated by pauses 
and renewals of movement, and by massive outbursts of vol- 
canism that accounted for the repeated readvances of the ice 
in North America, and by warm phases between these read- 
vances, when the temperatures may have been warmed by 
the increasing percentage of carbon dioxide in the air, we 
may attempt to reconstruct the progression of events in 
Siberia. This may furnish a basis for the interpretation of the 
report, and of the other facts about the mammoths cited 
above. 

To begin with, if North America was moving gradually 
southward during this period (along the goth meridian, as 
we assume), then East Asia was moving northward along the 
continuation of the same meridian, and it moved at the same 



250 EARTH'S SHIFTING CRUST 

rate, to the same distance, with the same pauses, if any. The 
climate would be growing gradually colder, but with inter- 
ruptions, for the colder and warmer phases caused in North 
America by the volcanic dust and carbon dioxide (produced 
by volcanic eruptions) would be universal; they would affect 
the whole earth's surface in the same direction at the same 
time. In Siberia, warm phases would check the deterioration 
of the climate temporarily, while in North America the cold 
phases would act to check its improvement. The total change 
of climate in Siberia during this whole period would be very 
great. Siberia would, at the beginning of the movement, have 
been enjoying a warm temperate climate, warmer than that 
of New York at the present time. 

During the whole period, changes would gradually be tak- 
ing place in the flora in eastern Siberia. Plants adapted to 
wide ranges of climate, capable of surviving in the increasing 
cold, would continue to grow in Siberia. It is interesting to 
note in the foregoing report of the contents of the mam- 
moth's stomach that every single plant or tree associated 
with the time of the mammoth's death has a range extending 
considerably to the south of that latitude today. Plants un- 
able to survive in the increasing cold would retreat toward 
the south, as two or three of the plants found in the stomach 
evidently did. Arctic species and varieties would tend to in- 
vade the region as the climate grew colder. The contents of 
the mammoth's stomach would simply represent the mixture 
of plants growing in Siberia during the particular part of the 
period in which he lived. We learn from Runcorn that Soviet 
scientists have dated a mammoth from the Taimir Peninsula, 
considerably to the westward in Siberia, by radiocarbon, and 
have found it to be about 12,300 years old (361). This means 
that mammoths survived until toward the end of the crust 
movement. The mammoth of the Beresovka may have lived 
as late as or later than this, when the climate of Siberia had 
deteriorated a great deal, though by no means to the present 
level. The possibility exists that if we could find a mammoth 
that had died during the earlier phase of the displacement 



THE GREAT EXTINCTIONS 251 

we would find a combination of plants in its stomach reflect- 
ing a much warmer climate, but, of course, it is unlikely that 
during that warmer period any mammoths would have been 
preserved. 

Just as we assume that North America subsided a thousand 
feet or more relatively to sea level when the continent was 
being moved equatorward, this being followed by a later 
isostatic rebound of the crust, so we must logically assume a 
progressive uplift of Siberia during its poleward displace- 
ment, with subsidence since. 

This uplift of Siberia, which I now suggest, is vitally im- 
portant for the clarification of the facts relating to the mam- 
moths. If we assume that, previous to the displacement, the 
elevation of the lands in eastern Siberia and the Arctic was 
about the same as now, we can see in this moderate uplift 
(which is a necessary corollary of crust displacement) suffi- 
cient added elevation to connect both the New Siberian 
Islands with the Asiatic mainland, and Asia with North 
America across the Behring Strait. Thus the migrations of the 
animals to the New Siberian Islands and between Alaska and 
Siberia are explained, without having to have recourse to 
the theory of a sea level controlled by glacial melt water. 
Then, the subsidence of the area by isostatic adjustment after 
the end of the displacement (let us say, between 10,000 and 
3,000 years ago) would have separated America, Asia, and the 
New Siberian Islands, and it provides us with a clear and 
sufficient explanation for the reported dredging up of mam- 
moths' tusks from the bottom of the Arctic Ocean, or of their 
being thrown up, as it is said, upon the beaches of the Arctic 
Ocean during Arctic storms. 

The progressive elevation of Siberia during the displace- 
ment provides us, finally, with a very complete explanation 
of the many curious, enigmatic circumstances surrounding 
the discovery of the mammoths' remains, and those of other 
animals. But before these problems can be explained, another 
circumstance must first be briefly discussed. 

I have mentioned that volcanic eruptions would be having 



252 EARTH'S SHIFTING CRUST 

their direct and indirect effects in Asia as in North America, 
and, indeed, everywhere. The effect o volcanic dust, as we 
have seen, is to chill the atmosphere. In the last chapter I 
presented indirect evidence that the volcanism during the 
displacement was at times massive enough to produce major 
lowering of the average temperature, and continuous enough 
to keep it low for long periods. In addition, I presented di- 
rect evidence that many volcanoes were active during the 
period in areas that are now quiet. 

I can form no idea as to just how many volcanoes might 
have been active simultaneously at any time during that dis- 
placement of the crust. An educated guess is apparently not 
possible. I will assume, however, that during any displace- 
ment the average quantity of volcanism annually would be 
considerably greater than at present. This seems a safe as- 
sumption. 

I will assume, secondly, that at intervals during the 10,000- 
year period of the displacement, volcanism would reach a 
higher point than the average for the whole period. This has 
already been suggested (Chapter VII). Such periods would be 
likely to occur while the crust was moving at its greatest speed, 
that is, during the middle part of the period (Chapter XI). 
These would be periods of readvance of the dwindling con- 
tinental icecap. They would be of varying length, but some 
of them would last a long time. 

My third supposition will be that occasionally, during 
periods of very active volcanism, there would occur a con- 
junction of several major volcanic explosions in the same 
year. The mathematical probabilities would favor this oc- 
currence. It would be strange indeed, considering the stresses 
and strains to which the crust of the earth would be sub- 
jected during its displacement, if this did not happen now 
and then. 

Let us now look at the consequences of this. Let us sup- 
pose five explosions in one year of the magnitude of the 
explosion of Mt. Katmai (or a larger number of lesser ex- 
plosions). According to Humphreys, this would produce 



THE GREAT EXTINCTIONS 253 

enough dust to intercept 100 per cent of the sun's radiation; 
consequently, the earth's surface would receive no heat at all. 
It seems very unlikely that things could ever have gone quite 
as far as this; nevertheless, considering that volcanic dust is 
circulated around the world in a matter of days, and that the 
refrigerating effects on the atmosphere may be felt in a 
matter of weeks or months, there exists the possibility of a 
sudden and drastic fall in temperature following soon after 
such a conjunction of volcanic explosions. 

The direct effects of this sudden fall in temperature on 
animals would be serious enough, but the indirect effects 
concern us more, for the moment. The amount of humidity 
the atmosphere can hold is proportional to temperature. If 
a mass of air is heated, it will pick up more moisture. If it is 
cooled drastically, the precipitation will be drastic, in the 
form of either rain or snow. At the same time, precipitation 
will be increased by an increase in the number of dust par- 
ticles in the air, because raindrops require dust particles to 
condense around, or so it is thought. Our situation, after a 
massive outburst of volcanism in a short period, would be 
that while the air was being drastically cooled, there would 
at the same time be an enormous increase of the convenient 
dust particles. This could add up to precipitation of moisture 
on an enormous scale. 

Now let us return to Siberia. Let us suppose that the 
region is being steadily moved northward, and that its eleva- 
tion above sea level is increasing. In a certain year, a conjunc- 
tion of several major volcanic eruptions takes place. Let us 
come back to our Beresovka mammoth. He is feeding quietly 
in the grassy meadow, and he has just swallowed a mouthful 
of buttercups, and has gathered up, with his trunk, a new 
mouthful of wild beans, The temperature is warm, and 
there is no sign of what is about to occur. The volcanoes have 
shot off their dust some time before. Cold air* currents are 
circulating ominously, but unperceived, not far away. 

I have seen a situation like this in Canada, during Indian 
summer. Day after day the sun is warm, although the nights 



254 EARTH'S SHIFTING CRUST 

are cold. The forest still has a summer look. It is still possible 
to swim in the lake, and then come out and stretch in the sun 
to get dry and warm. But suddenly, without transition, in 
the course of a few hours, the northwest wind brings winter. 
The lake freezes up, and the very next day, as far as the eye 
can see, there is nothing but ice and snow. 

Things moved faster, or at least more drastically, in the 
grassy meadow. The storm came down early in August, per- 
haps first with rain, and terrific wind. Humphreys has 
pointed out that the effect of a large quantity of volcanic 
dust in the atmosphere must be to increase the temperature 
gradient between the poles and the equator, resulting in 
more rapid circulation of the air, in winds of greater velocity. 
I shall present additional evidence of this in the following 
pages. Since winds occasionally attain a velocity of 150 miles 
an hour or more even today, we may conservatively suppose 
that the storm could have hit the grassy meadow at that 
speed. At the beginning of the disturbance, the mammoth 
would have stopped eatingwithout even bothering to swal- 
low the last few beans in his mouth. He would have left the 
meadow and, accompanied by his friends, sought shelter in 
the nearest forest, as, no doubt, he had often done before 
during storms. Here, in the confusion of the storm, perhaps 
because of the force of the wind itself, he may have fallen 
over the cliff at the bottom of which his body was found. He 
was not killed, but a leg bone and his pelvic bone were 
broken. He couldn't walk, so he lay there, while the wild 
hurricane in a very few hours brought down subzero air 
masses from the polar zone, and the rain turned to snow, and 
piled up around him. He lifted the fore part of his body as 
far as he could above the snow, but it piled up, in the lee of 
the cliff over which he had fallen, until it was above his head. 
By this time, however, he might already have frozen to death 
in his half-standing posture. A similar fate would have en- 
gulfed millions of animals. During the ensuing months of 
winter the snow mantle would still thicken, and during the 



THE GREAT EXTINCTIONS 255 

following summer, because of the continuing effects of the 
volcanic dust, it would scarcely melt at all. 

At this point many animals have been frozen into the 
snowdrifts; moreover, except for some that may have been 
dismembered by the force of the wind, they are intact. They 
are frozen in the ice of a nascent icecap. Since the region 
moves ever northward, the ice cover tends to remain over 
most of the area; it does not quite melt away during the 
summers, and it gets thicker and thicker as Siberia ap- 
proaches the pole. 

But here some impatient reader with some geological 
knowledge will break in and say, "But there was no icecap 
in Siberia! " Quite so: no continental icecap finally devel- 
oped; the icecap that began to grow never came to maturity. 
Instead, it melted away. 

One need not look far for the explanation of this. We have 
noted that the region was uplifted during the displacement. 
In the earlier stages, while the climate was still warm, the 
uplift had been sufficient to open land communications with 
the New Siberian Islands and Alaska. In climate, a slight in- 
crease of elevation may be the equivalent of hundreds of 
miles of latitude. So, after a movement of the crust had pro- 
gressed to a certain distance, and the resulting increased 
elevation of the land had brought lowered temperatures, a 
thin icecap stretched over northern Siberia. 

But when, after the end of the displacement, isostatic ad- 
justment began to correct the elevation, and to bring the 
area down, it also warmed the climate, and so the nascent 
icecap melted away, and no doubt this development was 
furthered by the Climatic Optimum. During this warm pe- 
riod, the ice sheet in Siberia may have melted very rapidly, 
and torrents of melt water may have borne the bodies of 
the animals along, after they were disengaged from the ice, 
and torn their bodies apart, and heaped them up in great 
numbers as we find them, and buried them in vast seas of 
freezing mud. In most cases, of course, only the bones re- 
mained. Brooks cites a statement by Flint and Dorsey (160: 



256 EARTH'S SHIFTING CRUST 

627) giving evidence of a recent "thin and inactive" ice 
sheet in Siberia, exactly as the hypothesis demands. 

It might frequently occur that an animal would escape 
being washed out of the melting icecap. It would seem that 
the Beresovka mammoth was one of these. He seems to have 
remained frozen in the attitude of his last struggle in the 
snowdrift. In a succession of thaws, however, the ice encasing 
his body was apparently washed away and replaced by freez- 
ing mud. The temperature of the carcass may have ap- 
proached the melting point at these times, but though this 
would have destroyed the edibility of the meat, it would not 
have disintegrated the body. It would even have been pos- 
sible for the outside of the body to have thawed briefly 
during its translation from the icecap to the permafrost with 
little or no decay, because of the absence of germs in the 
Arctic climate. It would seem that the Academicians who 
examined the mammoth in situ were not impressed with 
his edibility; they did not try any mammoth steaks. 

It appears that this assumption of a thin, temporary ice- 
cap in Siberia gradually transformed into permafrost solves 
most of the outstanding questions about the mammoths and 
the other animals whose remains are found in Siberia. It ex- 
plains, for example, why some of the mammoths have been 
found on the highest points of the tundra. It explains the 
configuration of the deposits in which they are found. It 
explains Tolmachev's remark that "mammoth-bearing drift 
deposits sometimes have a thickness of tens of feet, sometimes 
they are spread out in comparatively thin layers" (422:51). 
The "drift deposits" are water-formed; they can now be ex- 
plained as the result of the melting of the thin icecap, which 
must have produced rapidly flowing rivers that picked up 
and deposited quantities of mud, thicker in some places than 
in others, and filled with bodies and parts of bodies dropped 
out of the icecap. The prompt refreezing of these seas of 
mud, after the thaw, created the permafrost. 

But even if these assumptions seem to solve the problems, 
the reader may still say, "Wellvery good. But what if all 



THE GREAT EXTINCTIONS 257 

this isn't true after all?" All I can then do is to point to 
some tangible evidence that exactly this sort of thing hap- 
pened in another part of the earth. But to examine this evi- 
dence we must turn aside into one of the byways of science, 
and examine an unsuspected facet of the Wisconsin glacia- 
tion. We must return to North America, and reconstruct the 
story of the birth of that icecap. 



7. The Mastodons of New York 

About seventy-five years ago, considerable excitement was 
aroused in scientific and popular circles by the discovery of 
the remains of extinct animals in various parts of the United 
States. Perhaps the most sensational of these finds was that 
of the mastodons. Many of these were found in New York 
State, and in some cases they were so well preserved that it 
was still possible to analyze the contents of the animals' 
stomachs. Some extensive accounts of these mastodons have 
appeared in print (178, 309, 203). Since science, like clothing, 
has its fashions, a period of attention to the mastodons was 
followed by a period of neglect. Neglect did not overtake 
them, however, before conclusions were reached respecting 
them. It was noted that nearly all the best-preserved remains 
were found in bogs and swamps, where, it was assumed, they 
had been mired and sucked down to their deaths. 

This explanation of their deaths was accepted, apparently 
without any dissent, and it involved, of course, the acceptance 
also of the opinion that the animals had inhabited New York 
State after the departure of the ice sheet. It was concluded 
that the animals were postglacial. The conclusion was inevi- 
table, because the ice sheet would have plowed up all bogs, 
and the animals' bodies could not have been preserved from 
destruction by it. 

So the matter rested the mastodons ceased to attract at- 
tention. There followed a period during which the general 
trend of scientific opinion led finally to the view that neither 



258 EARTH'S SHIFTING CRUST 

mammoths nor mastodons, nor any of the other extinct Pleis- 
tocene animals, had lived in North America after the ice age. 
But no one has gone back to dig up the evidence of the mas- 
todons and ask how, if they did not live in New York State 
after the ice age, they came to be buried in the bogs where 
they are found. It is now our task to reopen this closed chap- 
ter, to drag these ancient beasts once more from their tomb. 
We shall first look at some of their case histories, and then 
summarize our findings. 

One might imagine two alternative solutions of the prob- 
lem. Either the mastodons lived in New York State after the 
ice age, and got themselves mired in the bogs where their 
bodies are found, or they got mired in the bogs before the ice 
age, and somehow escaped destruction by the passage over 
them of the mile-thick ice sheet. In the latter case, the ani- 
mals would have been found in beds of swampy vegetable 
stuff below the sand, gravel, and striated stones deposited by 
the glacier. How, then, are we to explain the fact that the 
animal remains are not found in this layer but are mixed 
up with the glacial materials themselves? Since this is usually 
true, we are driven to the conclusion that the animals were 
mired in New York State bogs neither before nor after the 
coming of the ice sheet. Before pressing on to further con- 
clusions, let us consider the details of a few cases. 

In August, 1871, a mastodon was discovered one mile 
north of Jamestown, New York, and the remains were ex- 
amined in situ by Professor S. G. Love and others. Love de- 
scribed the find as follows: 

On the east side of the Fredonia road, about one mile north of 
Jamestown, is the farm of Joel L. Hoyt. About 500 yards from the 
road is a sink or slough covering about an acre, possibly more in ex- 
tent, and varying from two to eight feet in depth, and fed by several 
living springs. Cattle have been mired and lost there since the farm 
was first occupied. Mr. Hoyt drained the sink and left the muck to 
dry, and later commenced an excavation there. The work of excava- 
tion had continued a little more than a week, when the workmen 
began to find (as they supposed) a peculiar kind of wood and roots, 



THE GREAT EXTINCTIONS 259 

imbedded some six feet beneath the surface. For several days they 
continued to carry the small pieces into an adjoining field with the 
muck, and to pile the larger ones with pine roots and stumps to be 
burned. But Mr. Hoyt discovered unmistakable evidences of the re- 
mains of some huge animal. At once there was a change in the pro- 
cedure, in order to secure specimens and determine their character. 
It was difficult to determine the precise position of the remains, as 
they were much disturbed and partially removed before any special 
notice was taken of them. From the best information I could get, I 
conclude that the body lay with the head to the east, from four to six 
feet beneath the surface, and in a partially natural position. Many 
of the bones were, however, out of place. The lower jaw was about 
five feet from the head and lay on the side crushed together so that 
the rows of teeth were very near each other. The tusks extended 
easterly in nearly a natural position, and, judging from the statements 
of Mr. Hoyt and the workmen, they must have been from ten to 
twelve feet in length. After digging into the gravel and clay about 
ten inches I found traces of a rib, decayed but distinctly marked, 
over five feet in length. Where the body must have lain were found 
large quantities of vegetable matter (evidently the contents of the 
stomach) mostly decayed, in which were innumerable small twigs 
varying from one half inch to two inches in length. The remains were 
all in a very forward state of decay; and when I reached the ground 
I found it possible to do little more than had already been done to 
preserve them. . . . (203:14-15). [There follows a list of individual 
parts found.] 

Here an important point is the fact that parts of the re- 
mains were found mixed with the sand and gravel, which 
had been deposited by the ice sheet as it retreated. This fact 
suggests that the carcass may have been dropped or washed 
out of the icecap into a glacial pool, which later through a 
process of countless freezings and thawings and accumula- 
tion of sediments became a bog. Later Professor Love am- 
plified the foregoing remarks in a very interesting manner, 
in a paper read before the Chautauqua Society of History 
and Natural Science, July 16, 1885: 

The twigs found in such large quantities where the stomach would 
naturally be were found, upon microscopical examination and com- 
parison, to be of the same kind (genera and species) as the cone bear- 
ing trees (pine and spruce) of the present day. Mingled with the twigs 



260 EARTH'S SHIFTING CRUST 

was a mass of yellowish fetid matter, probably the remains of some 
vegetation which did not possess the staying qualities of the balsamic 
cone-bearers (203:15-16). 

Several important points are illustrated in these passages. 
They are all brought out, as well, in numerous other cases. 
The more significant points appear to be: 

a. The rib was found buried in the glacial material under 
the muck, as already mentioned. 

b. Some force crushed the jaw and separated other parts of 
the body, without completely disturbing its natural position. 
We shall find many cases of this sort of thing. 

c. The stomach was found to contain evidence of vegeta- 
tion such as now grows in New York State. Since the animal 
did not live after glacial times, and since the vegetation 
naturally did not exist in New York State when it was cov- 
ered by a mile of ice, it follows that the animal lived in the 
last Interglacial Period, and that New York then had a cli- 
mate something like the present. 

d. The discovery of the remains in a mire tells us nothing 
of the mode of death, because only in a mire would they 
have had any chance of being preserved. Animals dying in 
other situations, or left in dry places by the retreating ice, 
would have disintegrated completely. 

e. The evidence favors the conclusion that the body of 
the mastodon was preserved within the vast ice sheet itself, 
and was deposited when the ice withdrew, in a bog where 
conditions continued to favor its preservation. The power of 
bogs to preserve animal and vegetable matter for long pe- 
riods is well known. 

The instances cited by Hartnagel and Bishop of mastodons 
that clearly were not mired in bogs include one mastodon 
whose remains, a tusk, were found in sand near Fairport; 
another whose tusk and teeth were found in sand and gravel 
in the town of Perrinton; one whose remains (ribs, skull, 
tusk, leg bone) were found "about four feet below the sur- 
face in a hollow or water course, lying on and in a very hard 
body of blue clay, and about two feet above the polished 



THE GREAT EXTINCTIONS g6l 

limestone . . ."; "a rib of a mammoth or mastodon found 
12 feet below the surface of the ground in gravel" at Roches- 
ter, and other instances (203:35-39). 

Dr. Roy L. Moodie, of the New York State Museum, in 
his Popular Guide to the Nature and the Environment of the 
Fossil Vertebrates of New York, discusses a mastodon that 
was deposited entire in a glacial pothole: 

. . . The pothole was made by whirling waters grinding the loose 
stones in a depression, gradually deepening in the post-glacial Mo- 
hawk River, and the body of the mammoth carne down with the ice 
and dropped into the hole. . . . (309:103-05). 

This particular case provides an excellent illustration of the 
process by which so many of the animal bodies were torn 
apart, not only in New York State but also probably in Si- 
beria, where the melting of a thinner ice sheet would still 
have produced torrents in which the bodies detached from 
the ice could be dashed against rocks and broken to pieces. 
Hartnagel and Bishop, referring to the few remains of 
mammoths that have been found in New York State, remark: 

There is no doubt that the mammoth remains were imbedded in 
the sand and gravels laid down during the recession of the ice sheet. 
Examples of these are best seen in the Lewiston specimens of teeth 
and bones which were found deeply buried in the spit formed in Lake 
Iroquois. . . . (203:67). 

Sir Charles Lyell visited the site of the discovery of a mas- 
todon near Geneseo, Livingston County, New York, and 
described his observations in his Travels in North America^ 
in a passage quoted by Hartnagel and Bishop: 

I was desirous of knowing whether any shells accompanied the 
bones, and whether they were of recent species. Mr. Hall and I there- 
fore procured workmen, who were soon joined by some amateurs o 
Geneseo, and a pit was dug to a depth of about five feet from the 
surface. Here we came upon a bed of white shell marl and sand, in 
which lay portions of the skull, ivory tusk and vertebrae, of the ex- 
tinct quadruped. The shells proved to be all of existing freshwater 
and land species now common to this district. I had been told that 
the mastodon's teeth were taken out of muck, or the black superficial 



262 EARTH'S SHIFTING CRUST 

peaty earth of the bog. I was therefore glad to ascertain that it was 
really buried in the shell-marl below the peat, and therefore agreed 
in situation with the large fossil elks of Ireland, which, though often 
said to occur in peat, are in fact met with in subjacent beds of marl 
(203:31-32). 

Let us, in passing, note in this passage the evidence that 
whatever occurred in Siberia and in North America (though 
perhaps at different times) seems also to have occurred in 
Ireland. 

If it is now clear that the mastodons were actually con- 
tained in the great continental glacier, a question may arise 
as to their probable numbers. Were these animals rare or did 
they exist in great herds? Hartnagel and Bishop quote an 
earlier writer, who remarked: 

... I have been particular in stating the relative situations and 
distances of those places in which bones have been discovered, from 
a certain point, to show, from the small district in which many dis- 
coveries have been made, the great probability that these animals 
must have been very numerous in this part of the country, for if we 
compare the small proportion that swamps, in which only they are 
found, bear to the rest of the surface, and the very small proportion 
that those parts of such swamps as have yet been explored, bear to 
the whole of such swamps, the probable conclusion is that they must 
once have existed here in great numbers (203:62). 

It must not be supposed that only mastodons and some 
mammoths were thus caught in the ice sheet and deposited 
as it retreated. Hartnagel and Bishop give instances of the 
finding of remains of foxes, horses, large bears, black bears, 
giant beaver, small beaver, peccaries, deer, elk, caribou, 
moose, and bison, forming a mixture of extinct and still 
living species, all deposited in the same way (203:81-94). 
Moreover, discoveries were not confined to New York State, 
but embraced the entire area once covered by the great ice 
sheet 

We must therefore conclude that in all probability some 
millions of all these sorts of animals were enclosed in the ice 
sheet. Now the question must be asked, Did they live in the 
regions where they are now found, or were they carried 



THE GREAT EXTINCTIONS 263 

greater or lesser distances by the moving ice? This is an im- 
portant question. Glaciers often carry vast quantities of de- 
bris, even huge boulders, hundreds of miles, even in some 
cases uphill (63:14-15). Hartnagel and Bishop give an ex- 
cellent description of the way in which a great ice sheet 
moves, and provide a partial answer to the question, in the 
following passage: 

The remains of most of the Canadian animals that were over- 
whelmed in and by the glacial snows were incorporated in the lower, 
or ground-contact ice of the southward moving sector of the Quebec 
(Labradorian) ice cap. The deepest portion of the ice cap was pushed 
into the deep Ontarian valley and becoming stagnant because of its 
position and also because of its load of detritus, it served during all 
the duration of the Quebec glacier as a bridge over which the upper 
ice, by a shearing flow, passed on south over New York. This element 
of glacier mechanics is fundamental to the present explanation of the 
peculiar distribution of the Elephas remains and is believed to de- 
scribe the behavior of the continental glacier toward deep and 
capacious valleys, not only those transverse to the ice flow but also 
longitudinal valleys. . . . (203:69). 

This statement should be supplemented by Coleman's re- 
mark that a great continental icecap, independently of any 
valleys, moves only in its upper layers, except at the edges. 
The layers near the ground are stagnant. This is the reason, 
he says, that the evidences of glaciation are found mostly on 
the exterior fringes of the area once occupied by the ice 
sheet. The central areas escape the grinding and plowing 
up that leave such evidences in the latter areas. 

The usual explanation of this remarkable fact leaves some- 
thing to be desired. According to the accepted concept, an 
ice sheet forms first in a small area, and then spreads out, 
presumably after it has become thick enough to move out- 
ward by the force of gravity. That means, it seems to me, 
that all but a small central area should show signs of having 
been passed over by the glacier. Yet, according to Coleman, 
the opposite is the case. 

I think our assumption provides a good answer to this 
problem, for the initial snows, such as we assume may have 



264 EARTH'S SHIFTING CRUST 

occurred in Siberia as the result of dust produced by massive 
outbreaks of volcanism, would cover a considerable area, 
enclosing the animal remains. Later, if the ice sheet de- 
veloped enough to move by gravity, the upper layers would 
move, leaving a stagnant layer, at least in some places, to pro- 
tect the animals, and only at the remote fringe or at high 
points of the area would the now moving icecap containing 
its load of rocks and pebbles be continuously in contact with 
the ground. In Siberia the icecap, if there was one, never 
grew thick enough to move by gravity. In North America, 
on the other hand (at an earlier time), the icecap did grow, 
until it began to move. 

So we may conclude that the animals contained in the 
great North American icecap were mostly living, at the time 
they were overwhelmed by the snow, in the places where 
they are now found. It would not be wise, of course, to ex- 
clude entirely the transportation of animal remains in the 
ice sheet; very certainly it occurred, and perhaps quite often, 
but in all probability the vast majority of the animals were 
in the stagnant ground-contact ice. We have seen that the 
animals represented in the collection in the glacier indicate 
a temperate climate, like that prevailing in New York State 
today. Now the final question is, How did these millions of 
animals, living in a temperate zone, get caught in the ice 
sheet? 

Note that here there is no dispute about the climate at 
the time the animals were living. Here the situation is free 
from the uncertainty surrounding the exact climate in which 
the Beresovka mammoth lived. The animals listed above are 
sufficient in themselves to establish the fact of a temperate 
climate; however, there is an additional piece of evidence, 
in the form of a quite fascinating botanical analysis of the 
contents of a mastodon's stomach. Hartnagel and Bishop 
quote from a report by Dr. J. C. Hunt: 

The remains, both of cryptogams and flowering species, were in 
abundance. Stems and leaves of mosses were wonderfully distinct in 
structure, so much so that I could draw every cell. I even readily de- 



THE GREAT EXTINCTIONS 265 

tected confervoid filaments, with cells arranged in linear series, re- 
sembling species now found in our waters. Numerous black bodies, 
probably spores of the mosses, were found in abundance. Not a frag- 
ment of sphagnum was seen in the deposit. I found, however, one 
fragment of a water plant, possibly a rush, an inch long, every cell 
of which was as distinct as though growing but yesterday. Pieces of 
the woody tissue and bark of herbaceous plants, spiral vessels, etc., 
were abundant. Carapaces of Entomostraca were present, but no trace 
of coniferous plants could be detected. It hence appears that the 
animal ate his last meal from the tender mosses and boughs of flower- 
ing plants growing on the banks of the streams and margins of the 
swamps, rather than fed on submerged plants; and it is probable, 
moreover, that the pines and cedars, and their allies, formed no part 
of the mastodon's diet (203:58). 

Here we see that everything indicates a climate similar to 
that of New York today. An interesting point is the differ- 
ence between the mastodon's diet indicated here and that 
indicated in the case mentioned earlier. Speculation suggests 
that perhaps the diet in this second case indicates the ani- 
mal's preferred diet, or perhaps merely the diet available in 
the summer, while that in the earlier case, in which twigs 
were so important, may represent either the winter diet of 
the mastodon or an emergency diet, the result of the de- 
struction of the normal diet by the events occurring just be- 
fore the animal's death. In any case, the second diet indicates 
that whatever happened to that mastodon certainly took 
place in the summer. 

Now it is obvious that the arguments used to explain away 
the evidence of climatic change in Siberia won't work in New 
York. Here there was certainly climatic change, with a venge- 
ance. The explanation I have offered for the preservation 
of the Siberian remains will cover both cases. The great dif- 
ference between them, aside from the failure of the Siberian 
ice sheet to develop into a real icecap, consists of the fact that 
while the melting of the thin Siberian ice sheet left a perma- 
frost in which many remains could be preserved, the melting 
of the Wisconsin icecap left temperate conditions in which 
nothing could be preserved except what happened to find 



sj66 EARTH'S SHIFTING CRUST 

itself in bogs. Thus the great accumulations of bodies, such 
as are found in Siberia, and such as probably also were piled 
up by the rushing torrents coming from the melting Wis- 
consin icecap, simply rotted away and left not a trace behind. 
Now that we have satisfactorily established that the masto- 
dons were imprisoned in the Wisconsin icecap itself, it is 
necessary to add the correction that, despite this, they also 
survived the ice age, at least in western North America. 
Radiocarbon dates from 9,600 to 5,300 years ago have been 
found for some mastodon remains. It must be conceded that 
they may possibly have survived in North America until a 
much later date than this. They therefore could have lived 
in New York State after the ice age and have been caught in 
bogs. But they must also have lived in New York State before 
the ice age and been caught in the icecap, for otherwise their 
remains would not have been found in so many cases inter- 
mixed with the glacial materials (434). 



8. Storm! 

I have referred to the possibility that the extinction of ani- 
mals and preservation of their bodies may be accounted for 
in part by violent atmospheric disturbances, and I have of- 
fered some evidence that such disturbances did accompany 
the last displacement of the crust, and therefore, presum- 
ably, earlier displacements. 

It may be hard to distinguish between the effects on ani- 
mal life of ice action (that is, of being melted out of glaciers 
and subjected to the action of glacial streams) and the effects 
of atmospheric factors. Nevertheless, perhaps some evidence 
of the operation of the atmospheric factors is available. 

The evidence is presented, in part, by Professor Frank C. 
Hibben, in The Lost Americans, and since his description of 
the evidence is firsthand, and is presented so clearly, I have 
asked his permission to reproduce the pertinent passages. 

He begins with a general description of the Alaskan muck, 



THE GREAT EXTINCTIONS 267 

in which enormous quantities of bones (and even parts of 
bodies) are found: 

In many places the Alaskan muck is packed with animal bones and 
debris in trainload lots. Bones of mammoth, mastodon, several kinds 
of bison, horses, wolves, bears, and lions tell a story of a f aunal popu- 
lation. . . . 

The Alaskan muck is like a fine, dark gray sand. . . . Within this 
mass, frozen solid, lie the twisted parts of animals and trees inter- 
mingled with lenses of ice and layers of peat and mosses. It looks as 
though in the midst of some cataclysmic catastrophe of ten thousand 
years ago the whole Alaskan world of living animals and plants was 
suddenly frozen in midmotion in a grim charade. . . . 

Throughout the Yukon and its tributaries, the gnawing currents 
of the river had eaten into many a frozen bank of muck to reveal 
bones and tusks of these animals protruding at all levels. Whole 
gravel bars in the muddy river were formed of the jumbled fragments 
of animal remains. . . . (212:90-92). 

In a later chapter Professor Hibben writes: 

The Pleistocene period ended in death. This is no ordinary extinc- 
tion of a vague geological period which fizzled to an uncertain end. 
This death was catastrophic and all-inclusive. . . . The large animals 
that had given their name to the period became extinct. Their death 
marked the end of an era. 

But how did they die? What caused the extinction of forty million 
animals? This mystery forms one of the oldest detective stories in the 
world. A good detective story involves humans and death. These 
conditions are met at the end of the Pleistocene. In this particular 
case, the death was of such colossal proportions as to be staggering to 
contemplate. . . . 

The "corpus delicti" of the deceased in this mystery may be found 
almost everywhere ... the animals of the period wandered into 
every corner of the New World not actually covered by the ice sheets. 
Their bones lie bleaching on the sands of Florida and in the gravels 
of New Jersey. They weather out of the dry terraces of Texas and 
protrude from the sticky ooze of the tar pits of Wiltshire Boulevard 
in Los Angeles. Thousands of these remains have been encountered 
in Mexico and even in South America. The bodies lie as articulated 
skeletons revealed by dust storms, or as isolated bones and fragments 
in ditches or canals. The bodies of the victims are everywhere in evi- 
dence. 

It might at first appear that many of these great animals died 



268 EARTH'S SHIFTING CRUST 

natural deaths; that is, that the remains that we find in the Pleistocene 
strata over the continent represent the normal death that ends the 
ordinary life cycle. However, where we can study these animals in 
some detail, such as in the great bone pits of Nebraska, we find liter- 
ally thousands of these remains together. The young lie with the old, 
foal with dam and calf with cow. Whole herds of animals were appar- 
ently killed together, overcome by some common power. 

We have already seen that the muck pits of Alaska are filled with 
the evidences of universal death. Mingled in these frozen masses are 
the remains of many thousands of animals killed in their prime. The 
best evidence we could have that this Pleistocene death was not sim- 
ply a case of the bison and the mammoth dying after their normal 
span of years is found in the Alaskan muck. In this dark gray frozen 
stuff is preserved, quite commonly, fragments of ligaments, skin, hair, 
and even flesh. We have gained from the muck pits of the Yukon 
Valley a picture of quick extinction. The evidences of violence there 
are as obvious as in the horror camps of Germany. Such piles of 
bodies of animals or men simply do not occur by any ordinary natural 
means. . . . (212:168-70). 

So far, Professor Hibben's description of the evidence in 
Alaska may be consistent with the solution I have suggested 
for the evidence in Siberia, and for the area of the former 
Wisconsin icecap. No doubt Alaska also had a temporary 
icecap, since it was, in effect, merely an extension of Siberia, 
and apparently had the same kinds of animals at about the 
same time. However, it is evident that the animals that were 
killed far to the south, in Florida, Texas, Mexico, and 
South America, cannot have been contained in any icecap, 
whether thin or thick. Professor Hibben suggests that other 
factors were at work. 

One of the most interesting of the theories of the Pleistocene end 
is that which explains this ancient tragedy by world-wide, earth- 
shaking volcanic eruptions of catastrophic violence. This bizarre idea, 
queerly enough, has considerable support, especially in the Alaskan 
and Siberian regions. Interspersed in the muck depths and sometimes 
through the very piles of bones .and tusks themselves are layers of 
volcanic ash. There is no doubt that coincidental with the end of the 
Pleistocene animals, at least in Alaska, there were volcanic eruptions 
of tremendous proportions. It stands to reason that animals whose 
flesh is still preserved must have been killed and buried quickly to 



THE GREAT EXTINCTIONS 269 

be preserved at all. Bodies that die and lie on the surface soon dis- 
integrate and the bones are scattered. A volcanic eruption would ex- 
plain the end of the Alaskan animals all at one time, and in a manner 
that would satisfy the evidences there as we know them. The herds 
would be killed in their tracks either by the blanket of volcanic ash 
covering them and causing death by heat or suffocation, or, indirectly, 
by volcanic gases. Toxic clouds of gas from volcanic upheavals could 
well cause death on a gigantic scale. . . . 

Throughout the Alaskan mucks, too, there is evidence of atmos- 
pheric disturbances of unparalleled violence. Mammoth and bison 
alike were torn and twisted as though by a cosmic hand in Godly 
rage. In one place, we can find the foreleg and shoulder of a mam- 
moth with portions of the flesh and the toenails and the hair still 
clinging to the blackened bones. Close by is the neck and skull of a 
bison with the vertebrae clinging together with tendons and liga- 
ments and the chitinous covering of the horns intact. There is no 
mark of a knife or cutting instrument. The animals were simply torn 
apart and scattered over the landscape like things of straw and string, 
even though some of them weighed several tons. Mixed with the piles 
of bones are trees, also twisted and torn and piled in tangled groups; 
and the whole is covered with fine sifting muck, then frozen solid. 

Storms, too, accompany volcanic disturbances of the proportions 
indicated here. Differences in temperature and the influence of the 
cubic miles of ash and pumice thrown into the air by eruptions of 
this sort might well produce winds and blasts of inconceivable vio- 
lence. If this is the explanation of the end of all this animal life, the 
Pleistocene period was terminated by a very exciting time indeed 
(212:176-78). 

In Chapters IV and VII we saw that volcanic eruptions, 
possibly on a great scale, are a corollary of any displacement 
of the crust; therefore, our theory strongly supports and re- 
inforces the suggestions advanced by Professor Hibben, and 
at the same time his evidence strongly supports our theory. 
But Professor Hibben points out certain consequences that 
would flow from our theory, which I have not stressed. Wher- 
ever volcanism is very intensive, toxic gases could locally be 
very effective in destroying life. This is also true of violent 
local windstorms. Massive volcanic eruptions might, of 
course, occur anywhere on earth during a movement of the 
crust, and we saw, in Chapter VII, that they apparently oc- 



270 EARTH'S SHIFTING CRUST 

curred in a good many places, some of them far removed 
from the ice sheets themselves. 

Despite the unquestionable importance of these locally 
acting factors, it seems that we must give much greater im- 
portance to the meteorological results of the universally act- 
ing volcanic dust. As we have noted, this dust has a powerful 
effect in reducing the average temperatures of the earth's 
surface. A sufficient fall in temperature could easily wipe out 
large numbers of animals, either directly, or by killing their 
food, or even by favoring the spread of epidemic diseases. 
Then, the dust could greatly increase rainfall, which, in cer- 
tain circumstances, would produce extensive floods, thus 
drowning numbers of animals and perhaps piling their bod- 
ies in certain spots. As already mentioned, the dust would 
also act to increase the temperature differences between the 
climatic zones (the temperature gradient), thereby increasing, 
perhaps very noticeably, the average wind velocities every- 
where. Violent gales, lasting for days at a time, and recurring 
frequently throughout the year, might raise great dust storms, 
in which animals might be caught and killed by thirst or suf- 
focation. It must not be forgotten that, at the same time, 
changes in land elevations would be in progress, and these 
also would be affecting the climate and the availability of 
food supplies. The gradual character of these changes would 
be punctuated, at times, by the abrupt release of accumulat- 
ing tensions in the crust, accompanied by terrific earthquakes 
and by sudden changes of elevation locally amounting per- 
haps to a good many feet, which also could be the cause of 
floods either inland (by the sudden damming of rivers) or 
along the coasts. There is, as a matter of fact, as already 
mentioned, much evidence of turbulence throughout the 
world, during the last North American ice age, not only in 
the air but in the sea. 

I have not been able to make a complete survey of this evi- 
dence. Nevertheless, a few additional items have come to my 
attention. Ericson, for example, finds that turbidity currents 
in the sea were more powerful during the ice age than they 



THE GREAT EXTINCTIONS 271 

are today (141:217). Kulp found, by radiocarbon dating, that 
deposition of sediments along the eastern coast of North 
America occurred at a fast rate prior to about 15,000 years 
ago (262). Millis cited evidence of very violent winds during 
the melting phase of the Wisconsin icecap (308:14). Violent 
storms would seem a very natural explanation for the pe- 
culiar finds of many bodies of animals crammed into caverns 
and fissures, dating from various geological periods, that 
have been found in various parts of the world. Hibben men- 
tions one of these (212:173-74). It would seem possible that, 
in storms of the character that may have occurred, caverns 
may have been the only refuges available for man and beast 
alike. Dodson refers to the fact that the destruction of ani- 
mals in dust storms was apparently the cause of the preserva- 
tion of many fossils (115:77). Volchok and Kulp, in their ex- 
amination of ionium dating as applied to several Atlantic 
Ocean deep-sea cores, remarked that "at the close of the Wis- 
consin [glacial period] the rates of sedimentation for both 
sediment types [red clay and Globigerina ooze] increased by 
factors of 2-4" (442a:2ig). This means that the rate of dep- 
osition of sediment in the deep sea at these points was in- 
creased by from 200 to 400 per cent. This certainly suggests 
an unusual turbulence for the climate. 

It is little wonder that, faced by all these unpleasant con- 
ditions, a good many species in all parts of the world, even 
very far from the icecaps, gave up the struggle for existence. 

In conclusion, it appears to me that the whole mass of the 
evidence relative to the animal and plant remains in the 
Siberian tundra, interpreted in the light of the evidence 
from North America, sufficiently confirms the conclusion 
that there was a northward displacement of Siberia coinci- 
dent with the southward displacement of North America 
at the end of the 



IX : EARLIER DISPLACEMENTS 
OF THE CRUST 

/. Introduction 

According to the evidence presented in the last two chapters, 
the Hudson Bay region lay at the North Pole during the 
period of the Wisconsin ice sheet. It is not possible (with 
evidence now at hand) to define the geographical position 
of the pole more exactly; it may have been located in Hudson 
Bay itself, somewhat to the west in Keewatin, or somewhat to 
the east in the province of Quebec. Coleman refers to the 
fact that the earlier advance of the Wisconsin ice sheet en- 
tered Michigan from the north from the direction of Hud- 
son Bay rather than from Labrador (87:16). Flint remarks: 

... It is evident that in Gary time, the ice first entered Minnesota 
from the Rainy Lake District on the north, later from the northwest, 
and still later from the northeast via the Lake Superior basin. . . . 



Flint explains that all the known centers of the Wisconsin 
glaciation are relatively late; they date from the declining 
stage, when, according to our theory, the crust was in mo- 
tion. The evidence of the earlier centers would, he points 
out, have been destroyed by the ice flow of later times (375: 
171). It is evident that the two principal ice sheets in this re- 
gionthe so-called Keewatin and Labradorean ice sheets- 
were part of the same glaciation, and were contemporary, 
although the western center was the first to develop. Coleman 
mentions that this earlier phase of the ice sheet the so-called 
Keewatin transported boulders from the Laurentian area 
near Hudson Bay to the foothills of southern Alberta, depos- 
iting them at an altitude of 4,500 feet (87:15). This would 
indicate that the ice was moving westward from Hudson Bay. 



EARLIER DISPLACEMENTS OF CRUST 273 

It would also indicate that the ice sheet at this time was 
about a mile thick, while the Labrador ice sheet, at least 
in its later phases, was not nearly so thick (375:169). The 
suggestion here is strong that the pole was in Hudson Bay 
itself, and that the Labrador ice sheet began to develop 
when the main ice sheet was wasting. It is possible that it 
took over as the glacial center because the supply of moisture 
to feed the thinning icecap was better nearer the coast. This 
might have been the result, in part, of the opening up of 
water areas by the shrinking of the icecap. 

Now, it follows logically that if the Wisconsin ice sheet 
existed because the Hudson Bay region lay at the pole, and 
if it disappeared because of a displacement of the crust that 
moved North America away from the pole, then the Wiscon- 
sin ice sheet must have been brought into existence as the 
result of an earlier displacement. The question, therefore, 
now arises, Where was the pole situated previous to its loca- 
tion in or near Hudson Bay? It also becomes important to 
establish as closely as possible the date of this earlier dis- 
placement. 

We have already discussed the date of the beginning of the 
climatic change that produced the Wisconsin glaciation. A 
considerable amount of evidence has now accumulated that 
there were Wisconsin glacial phases earlier than the Farm- 
dale (133). Furthermore, we must remember that the Farm- 
dale date of 25,000 years ago is only the date of the invasion 
of Ohio by the ice sheet, which had previously to advance a 
long way from its center of origin. Evidence to be presented 
below will strongly support the conclusion that the begin- 
ning of the change of climatethat is, of the movement of 
the crust that eventually produced the Wisconsin icecap 
was about 50,000 years ago. This date, as we shall see, is 
not in conflict with evidence of cold climate in the North 
Atlantic extending back considerably further. 

With the date of the beginning of the Wisconsin glacia- 
tion tentatively fixed in this fashion, it is possible, by the use 



274 EARTH'S SHIFTING CRUST 

of certain methods of deduction, to reach an educated guess 
as to what area lay at the pole during the previous period. 

The method of locating a previous polar position is simple 
in principle, but very complicated in practice. The prin- 
ciple is to find a point on a circle drawn about the last estab- 
lished polar position with a radius of the same order of 
magnitude as the distance between the present pole and the 
last position. The assumption underlying this is that while 
one displacement may move the crust (and therefore shift the 
poles) farther than another, the chances are against any very 
great differences. It seems that the last displacement, which 
brought Hudson Bay down from the pole, amounted to 
about 2,000 miles on the meridian of maximum displace- 
ment. We shall therefore start out with the idea that the 
previous displacement may have been of about the same 
magnitude, but it can easily have been half as great or twice 
as great. This can later be checked with the field evidence. 

Our first step is to draw a circle around the hypothetical 
polar position in Hudson Bay, with a radius of 2,000 miles. 
Now, with a very liberal margin of error, we can assume that 
the previous pole lay somewhere near that circle. Our second 
step is to check the field evidence for past climates for the 
whole earth to see what position on or near that circle will 
explain the most facts. 

The difficulties encountered in assembling the evidence 
for a pole in Hudson Bay were very great, but they did not 
compare with the difficulties of establishing a reasonable 
case for the position of the previous pole. For this earlier 
period, embracing about 40,000 years, the evidence was much 
scantier. The margins of error on all climatic determinations 
had to be much greater. The numerous lines of evidence 
had to be examined in the light of the conscious and uncon- 
scious assumptions applied to them by previous workers, 
whose objectives and methods had been influenced by an 
entirely different set of ideas, and whose interpretations of 
the evidence might therefore be very different from mine. 



EARLIER DISPLACEMENTS OF CRUST 275 

The method used was that of trial and error. I selected a 
possible location, and then searched the available evidence 
to see whether that location was reasonable. I tried many 
locations, giving up one after another as facts turned out to 
conflict with each of them. 

After the Hudson Bay location had been settled to my 
satisfaction, I considered, for a while, that the previous posi- 
tion might have been in Scandinavia. I was forced to aban- 
don that idea. Other positions, investigated in turn, included 
Spitzbergen, Iceland, and Alberta. There was a great deal of 
shifting back and forth. 

Finally, clarity began to set in; ever more numerous facts 
began to fall into place, and at last I had reason to feel that 
my feet were on solid ground. The previous position of the 
pole was, I concluded, in or near southern Greenland, or 
between Greenland and Iceland. That is, the Greenland 
region then lay at the pole. 

I repeated the process, with this polar position as the cen- 
ter of my circle, and a rather flexible radius, and came up, 
to my considerable surprise, with a pole somewhere in or 
near Alaska, perhaps in the Alaska Peninsula or in the Aleu- 
tian Islands. This third pole takes us back to about 130,000 
years ago, and of course the evidence for it is much slighter 
than that for the Greenland pole. Despite the fact that this 
hypothetical position is hardly more than a suggestion to 
guide further research, it is highly important because it 
serves as a point of reference to "box in" the Greenland pole. 

It is impossible, with the evidence now at hand, to recon- 
struct any earlier displacements of the crust. However, evi- 
dence of a late Pleistocene continental glaciation in Eurasia 
suggests the possibility of one or two former polar zones in 
that land mass. Though this evidence has been known to 
Russian geologists for many years, it has attracted the atten- 
tion of Western geologists only since 1946 (219). One of these 
positions may account for the so-called "Riss" glaciation in 
Europe. 



276 



EARTH S SHIFTING CRUST 



90* 85' WEST FROM GREENWICH 




I 

S 




T 



95* 90* EAST FROM GREENWICH 



Fig. VII. Antarctica: Three Earlier Locations of the South Pole 

A corresponds to the North Pole in Alaska, B to the North Pole in Green- 

land, and G to the North Pole in Hudson Bay. Positions are approximate. 



At a still earlier time, western Canada may have lain at 
the pole, and this may account for the so-called Illinoisan 
glaciation the ice age that preceded the Sangamon Inter- 
glacial. However, since the quantity of the evidence declines 



EARLIER DISPLACEMENTS OF CRUST 277 

by a geometrical progression as we go backwards, clearly 
these earliest suggested positions for the crust are of value 
only as guides to research. 

I am suggesting three displacements of the crust in the 
last 130,000 years, the intervals between being of the order 
of 30,000 or 40,000 years. Considering the fact that the Wis- 
consin glaciation, if it started about 50,000 years ago, had 
an over-all span of about 40,000 years, it is not unreasonable 
to assume similar spans for the earlier periods, though per- 
haps we should allow for a considerable variation of their 
lengths. Whether this rapid pace was maintained all through 
the earth's history is a matter that perhaps cannot be settled 
at this time; however, I will discuss it briefly further on. 
So far as the Pleistocene is concerned, Suess and Emiliani, 
at least, see evidence that major climatic change did take 
place at that rate (409:357). Their explanation that climatic 
changes resulted from the cyclical astronomical curve of 
solar radiation is not convincing, for reasons already made 
clear. 

Much of the evidence that I will use to support this sug- 
gested series of displacements is in the form of cross sections 
of sedimentary deposits, called cores, which often singly em- 
brace very long periods of time. Rather than discuss each 
core separately, the simplest method will be to assemble the 
evidence from all the cores, so far as it bears on each sug- 
gested polar position in turn. The lines of evidence include 
marine cores from the Arctic, Antarctic, North Atlantic, 
Equatorial Atlantic, and South Pacific Oceans, and the Carib- 
bean Sea; many radiocarbon and oxygen isotope findings, 
pollen studies, and various evidences relating to the inter- 
glacial periods. The purpose of the presentation of this evi- 
dence will be to explain the known major climatic changes 
of the last 130,000 years, in terms of displacements of the 
earth's crust. Before attempting this reconstruction of the 
glacial history of the late Pleistocene Epoch, however, we 
must first discuss some of the current ideas in this field. 



278 EARTH'S SHIFTING CRUST 

2. Weakness of the Accepted Glacial Chronology 

Geologists are used to thinking of four major glaciations 
during the million-year period of the Pleistocene. They have 
assumed that each glaciation affected the earth as a whole 
simultaneously, causing ice sheets in both Northern and 
Southern Hemispheres, and lowered temperatures generally. 
Some geologists have questioned this concept of four glacia- 
tions; it is at least necessary to recognize several successive 
phases of advance and retreat for the older glaciations. 
Whether these interruptions were merely interstadials, like 
those of the Wisconsin glaciation, or were true interglacials 
it is increasingly hard to decide the further back in time one 
goes. According to the accompanying chart of the glacial 
periods (p. 282), it is evident that the intervals between the 
different stages of the major glacial periods are in some cases 
longer than the entire duration of the Wisconsin glaciation. 
It does not seem reasonable, therefore, to insist that they 
were merely interstadials, nor, consequently, to insist upon 
the number of just four glaciations during the Pleistocene. 
This becomes more apparent when we consider the im- 
plications of the Eurasian continental glaciation mentioned 
above. This, obviously, makes at least a fifth Pleistocene 
glaciation, but the matter does not end there. The question 
must be asked, If European geologists could overlook the 
evidences of this comparatively recent glaciation until the 
last decade (and this in spite of the fact that the evidences 
were spread widely over two continents, and had attracted 
the attention of Russian geologists as long as seventy-five 
years ago), how many other glaciations in various parts of 
the world may not have escaped attention? Flint has pointed 
out how easily glacial evidence can be destroyed (342:171), 
Coleman also emphasized the same thing: 

It might be supposed that so important a change would leave be- 
hind it evidence that no one could dispute, and that there should be 
no room for doubt as to what happened in so recent a time of the 



EARLIER DISPLACEMENTS OF CRUST 279 

earth's history. In reality the proof of the complete disappearance of 
the ice and its return at a later time is, in the nature of things, a 
matter of great difficulty and it is not surprising that there are differ- 
ences of opinion (87:20). 

Croll pointed out the ephemeral character of glacial evi- 
dence eighty years ago in books that are still eminently 
readable. After first discussing the accumulations of strata 
containing plant and animal remains during a period of 
temperate climate, he comments thus on their subsequent 
destruction: 

. . . We need not wonder that not a single vestige of [these strata] re- 
mains; for when the ice sheet again crept over the island [Britain] 
everything animate and inanimate would be ground down to powder. 
We are certain that prior to the glacial epoch our island must have 
been covered with life and vegetation. But not a single vestige of 
these is now to be found; no, not even of the very soil on which the 
vegetation grew. The solid rock itself upon which the soil lay has 
been ground down to mud by the ice sheet, and, to a large extent, as 
Professor Geikie remarks, swept away into the adjoining seas (91:257). 

It is obvious, of course, that whatever could destroy all the 
surface deposits of a temperate period would also, at the 
same time, destroy any evidences of former glaciations. Croll 
goes on to say: 

It is on a land surface that the principal traces of the action of 
ice during a glacial period are left, for it is there that the stones are 
chiefly striated, the rocks ground down, and the boulder clay formed. 
But where are all our ancient land surfaces? They are not to be found. 
The total thickness of the stratified rocks of Great Britain is, accord- 
ing to Professor Ramsay, nearly fourteen miles. But from the bottom 
to the top of this enormous pile of deposits there is hardly a single 
land surface to be detected. True, patches of old land surfaces of a 
local character exist, such, for example, as the dirt beds of Portland; 
but, with the exception of coal seams, every general formation from 
top to bottom has been accumulated under water, and none but the 
under-clays ever existed as a land surface. And it is here, in such a 
formation, that the geologist has to collect all his information regard- 
ing the existence of former glacial periods. . . . 

If we examine the matter fully we shall be led to conclude that 
the transformation of a land surface into a sea-bottom (by erosion and 



EARTH'S SHIFTING CRUST 

deposition of the sediments) will probably completely obliterate every 
trace of glaciation which the land surface may once have pre- 
sented. . . . 

The only evidence of the existence of land ice during former 
periods which we can reasonably expect to meet with in the stratified 
rocks, consists of erratic blocks which may have been transported by 
icebergs and dropped into the sea. But unless the glaciers of such 
periods reached the sea, we could not possibly possess even this evi- 
dence. Traces in the stratified rocks of the effects of land-ice during 
former epochs must, in the nature of things, be rare indeed (91:267- 
69). 

Croll was interested in pointing out the impermanence of 
glacial evidence. He continued, therefore, as follows: 

The reason why we now have, comparatively speaking, so little 
direct evidence of former glacial periods will be more forcibly im- 
pressed upon the mind, if we reflect on how difficult it would be in a 
million or so of years hence to find any trace of what we now call the 
glacial epoch. The striated stones would by that time be all, or nearly 
all, disintegrated, and the till washed away and deposited in the 
bottom of the sea as stratified sands and clays. . . . (91:270). 

In view of the facts presented by Croll, it would appear to 
be most unreasonable to insist on any fixed number of 
Pleistocene glaciations simply because hitherto it has been 
possible to group, in a very rough way, the comparatively 
few evidences we have in four glacial periods. 

It is a well-known fact that the chronology of four Pleisto- 
cene glaciations has been built up on the foundation of the 
assumption that all glacial epochs were the result of lowered 
world temperatures. Thus the European glaciations were 
declared to have been contemporary with the glaciations in 
America, although, as a matter of fact, no evidence of this 
existed. The assumption was based solely on astronomical 
and other theories of the causes of glaciation that we have 
shown to be inadequate. If the grouping of all European 
glacial evidences into only four major glaciations is ques- 
tionable, and if, in addition, there is no good evidence that 
these glaciations were really contemporary with those in 
America, then the possibility of a large number of different 



EARLIER DISPLACEMENTS OF CRUST 281 

glaciations in America and Europe during the Pleistocene 
must be taken seriously. 

If the number of these alleged major Pleistocene glacia- 
tions is not satisfactorily established, the attempts at dating 
them leave even more to be desired. A review of the past and 
current literature on the subject reveals lack of agreement. 
Estimates vary widely, and none of them has convincing sup- 
port. To make this plain, it is only necessary to compare the 
various estimates. The table on page 282 shows the estimates 
made by Penck and Bruckner, considered the leading Euro- 
pean experts (whose work, however, was done before the de- 
velopment of nuclear techniques of dating), and by Zeuner, 
whose estimates were endorsed by the climatologist Brooks. 
The reader will note that Zeuner divides each of the older 
glaciations into a number of substages, some of which are 
longer than the entire period covered by the Wisconsin 
glaciation. The reader will recall that the interstadials and 
the successive advances of the Wisconsin glaciation had dura- 
tions of the order of two or three thousand years; he may 
also note in the various cores shown later on that all the 
cores show brief climatic changes of the same magnitude. It 
is therefore impossible to concede that the earlier glaciations 
could have had interstadials 40,000 or more years long. The 
only explanation ever advanced for the oscillations of the Wis- 
consin ice sheet that I know of is the one advanced in this 
book: massive volcanism caused by displacement of the crust. 
This explanation cannot, however, be reasonably applied to 
oscillations 40,000 years in length. 

We see that the estimates of Zeuner (52: 107) and of Penck 
and Bruckner (52:107) are in profound disagreement. 

It would be easily possible to multiply the number of such 
contradictory estimates, or, if the reader pleases, he may ac- 
cumulate authorities who will support one of them; but is 
it not obvious that if leading professional geologists can differ 
to such an extent, no real reliance can be placed upon any of 
their very approximate and very speculative estimates? And 



28* 



EARTH'S SHIFTING CRUST 



TABLE II 

The Pleistocene Glaciations 



Zeuner 
(European) 

Wurm Glaciation 
Stage III 25,000 
Stage II 72,000 
Stage I 115,000 

Riss Glaciation 
Stage II 187,000 
Stage I 230,000 

Mindel Glaciation 
Stage II 435,000 
Stage I 476,000 

Gunz Glaciation 
Stage II 550,000 
Stage I 590,000 



Penck 8c Bruckner 
(European) 

40- 18,000 



130-100,000 



430-370,000 



520-490,000 



when, in addition, we find they have all been wrong as to 
the number of Pleistocene glaciations since a fifth one has 
just turned up are we not justified in dismissing all these 
estimates as speculations that are no longer worth discussing? 
If there is any doubt as to the reasonableness of this con- 
clusion, it should be put at rest by an entirely new estimate 
of the glacial chronology just produced by Emiliani. Emili- 
ani, working with marine cores, and applying some of the 
new techniques of dating, has found that the earliest Pleisto- 
cene glaciation occurred only 300,000 years ago, and that all 
the four recognized European glaciations, and their alleged 
American counterparts, have to be compressed into that 
comparatively short period (152). This finding, which there 
is no rational reason to reject, completes our picture; it 



EARLIER DISPLACEMENTS OF CRUST 283 

disposes, finally, it seems to me, of the traditional glacial 
chronology of the Pleistocene. 

As a consequence of this breakdown of the old theory, it 
seems to me that we must now start from the beginning, and 
build a new glacial chronology of the Pleistocene. Our 
method can only be the tested method of science: to proceed 
from the known to the unknown; from the Wisconsin gla- 
ciation, where our information is most ample, backwards. 



3. The Beginning of the Wisconsin Glaciation 

Examination indicates that, with the elimination of some 
mutually contradictory and evidently disturbed sediments, 
the three Ross Sea cores show a change from the deposition 
of glacial sediment to the deposition of temperate sediment 
on the Ross Sea bottom 40,000 years ago (p. 306). As a first step 
in establishing an approximate date for the beginning of the 
climatic change (that is, for the beginning of the movement 
of the crust) that was to produce, simultaneously, the tem- 
perate age in Antarctica and the glacial age in North Amer- 
ica, we must interpret the meaning of this change in the 
sediment. 

In the first place, the date itself is subject to some doubt. 
Two cores show the change at 40,000 years ago; one shows it 
a few thousand years later, but at the same time it also shows 
a change at 40,000 years ago from one type of glacial sedi- 
ment to another. The change in that core is from coarse to 
fine sediment, which in itself indicates amelioration of cli- 
mate. Thus, all three cores indicate at least some warming 
of the climate about 40,000 years ago. 

Now, what lapse of time must we allow between the be- 
ginning of the change of climate in Antarctica and the result- 
ing end of glacial deposition on the Ross Sea bottom? In the 
first place, we must remember that the movement of the crust 
would at first be entirely imperceptible. The speed of 
the displacement would increase slowly. After several thou- 



284 EARTH'S SHIFTING CRUST 

sand years a warming of the climate would be noticeable 
in the areas moving equatorward, and a cooling of the 
climate would occur in areas moving poleward, but these 
long-term trends of change would often be modified or 
even reversed by other factors. Massive volcanism would 
erupt before the crust had moved far, and the effect might 
be to check the retreat of the icecap, and even to cause its 
readvance after it began to retreat. We can see that this seems 
to have happened with the Wisconsin icecap: for thousands 
of years after it began to grow thinner, and to retreat, it 
went through phases of readvance. 

Before the final disappearance of glacial sediment from the 
Ross Sea bottom about 40,000 years ago, then, we must as- 
sume that the icecap then in Antarctica had gone through 
an initial phase of very gradual retreat, followed by perhaps 
several phases of readvance, until finally it withdrew entirely 
from the Ross Sea coast, and melted sufficiently to permit 
free-flowing rivers to bring down temperate-type sediment 
from the interior. It seems obvious, on the analogy of the 
Wisconsin icecap, that we should allow a period of time of 
the order of 10,000 years or so for this entire process. This 
suggests, then, that the movement of the crust began about 
50,000 years ago. However, it does not mean that the move- 
ment ended 40,000 years ago; it might even have continued for 
another 10,000 years. The cores contain no evidence on that 
point. It may have taken much more than 10,000 years to 
shift the crust. The core evidence, however, may be used to 
support the thesis that the crust displacement that brought 
the Hudson Bay region to the pole started about 50,000 years 
ago. In the following discussion we will tentatively consider 
that the previous position of the pole was in southern Green- 
land. 

a. The Arctic Cores 

In the last few years Soviet expeditions in the Arctic Ocean 
have taken a number of deep-sea cores, and have dated them 



EARLIER DISPLACEMENTS OF CRUST 285 

by the ionium method. These cores provide impressive con- 
firmation of the situation of the pole in North America dur- 
ing the Wisconsin glaciation, and, in addition, they furnish 
evidence of the approximate date of its migration to the 
Hudson Bay region from its previous position. 

The Soviet scientists were much impressed by their dis- 
covery that in the comparatively short period of the last 
50,000 years there have been no less than six major changes 
of climate in the Arctic Ocean. They did not find it easy to 
explain all these changes. They may all be explained, how- 
ever, by the hypothesis of two displacements of the earth's 
crust. 

The period begins with a very cold phase. Since the cores 
go back only 50,000 years, we do not know when the cold 
period began. The scientists remark: 

It seems that in the period in question, a considerable part of the 
Arctic shelf was dry; ther was no, or almost no, communication with 
the Atlantic. The climate was cold (364:9). 

According to the principles already set forth (Chapter IV), 
a pole in southern Greenland might be expected to have 
coincided with higher elevation of that general region, in- 
cluding the adjacent sea bottoms. The continental shelves 
in that part of the Arctic Ocean facing toward Scandinavia 
might well have been raised above sea level. There might 
well have been a land connection between Greenland and 
Iceland, and even across the narrow North Atlantic to Scan- 
dinavia. The Soviet scientists themselves strongly suggest 
that this land connection must have existed; nor are they 
alone in their suggestion. Years ago Humphreys advanced the 
idea. More recently Malaise has produced much new evi- 
dence for it (2 91 a). Thus it is evident that our theory has 
started out pretty well, by explaining why there was little 
communication between the two oceans. The interruption, 
however, was not simply the result of land masses in the 
North Atlantic. It could also have been the result of having 
a polar area lying right across the connections between the 



286 EARTH'S SHIFTING CRUST 

Arctic and the North Atlantic. A glance at the globe will 
make this clear. 

Beginning 50,000 years ago, and lasting for about 5,000 
years, there was, according to the Soviet scientists, a brief 
warm spell in the Arctic Ocean: 

. . . The bottom sediments became finer; argillaceous and highly 
argillaceous oozes began to be deposited, of a brown or here and 
there dark brown color, with increased contents of iron oxides, man- 
ganese, and foraminiferous micro-fauna (364:9). 

This warm period may reflect the movement of the crust 
that resulted in withdrawal of the pole from Greenland and 
its shift toward Hudson Bay. It is followed, however, by a 
cold period in the Arctic from 45,000 to 28-32,000 years ago. 
This following cold period is explained, according to our 
theory, by the beginning of the subsidence of the land bridge, 
which may have opened a water connection between the two 
oceans. The pole was at this time still near the Atlantic, and 
very cold Atlantic water was thus able to pour into the 
warmer Arctic. The subsidence of the land bridge as the pole 
moved away is, of course, a corollary of our theory. Such a 
subsidence in any area moving away from a pole would posi- 
tively have to occur, unless counteracted locally by the reloca- 
tion at particular points under the crust of lighter rock de- 
tached from the underside of the crust elsewhere. 

Following this cold period in the Arctic, we come to a 
most remarkable change, one which, in my opinion, provides 
an unusually impressive confirmation of our assumption of 
the location of the Hudson Bay region at the pole. About 
28-32,000 years ago, a really warm period began in the 
Arctic, and lasted until 18,000 to 20,000 years ago. The 
Soviet scientists have found that during this period there was 
a rich development of temperate-type microfauna in the 
Arctic, though their explanation is very different from ours: 

. . . The luxuriant development of a foraminiferal fauna of North 
Atlantic type testifies that during this period warm Atlantic waters 
were invading the Arctic Basin on a broad front; that is, communica- 
tion between the Arctic Basin and the Atlantic Ocean, which had 



EARLIER DISPLACEMENTS OF CRUST 287 

apparently been interrupted in the previous period, was reestablished. 
The duration of the warm period has been set at approximately ten 
to twelve thousand years (364:11). 

According to our interpretation, this luxuriant develop- 
ment of microorganisms of temperate type in the Arctic 
Ocean marks the movement of the pole into the interior of 
North America, and away from the Atlantic. This movement 
must have initiated a temperate period in all that half of the 
Arctic Ocean facing Scandinavia and Siberia. Again, a glance 
at the globe will make this clear. The reader cannot fail to 
see that with the pole in Hudson Bay, the Arctic and the 
Atlantic Oceans would lie on the same temperate parallel of 
latitude. 

This indication of temperate conditions in the Arctic 
gains enormously in significance when considered in connec- 
tion with the evidence of the Ross Sea cores for the same 
period in Antarctica. It seems that here we have evidence of 
warm periods near both the present poles. Yet, obviously, it 
is impossible to claim that the whole earth was warmer at the 
time, because of the evidence of widespread glacial condi- 
tions in both North America and Europe. It seems to me 
that a reasonable person is forced to the conclusion that the 
crust shifted. 

b. Earlier Phases of the Wisconsin Glaciation 

Let us briefly reconstruct the history of the crust displace- 
ment that resulted in the shift of the polar location from 
Greenland to Hudson Bay. This will explain the earlier, 
unknown phase of the Wisconsin glaciation. As has been 
pointed out, the earliest known phase of that glaciation is the 
Farmdale, only 25,000 years ago. Despite this fact, very many 
pieces of wood and other remains from glacial deposits in 
North America have been found to be much older than that. 
As already mentioned, Flint was led by this evidence to sug- 
gest that there must have been earlier glacial advances, the 
evidences of which were later destroyed. It has been shown 



288 EARTH'S SHIFTING CRUST 

that the Mankato Advance of the ice sheet occurred only 
1 1,000 years ago, and yet some deposits of Mankato age con- 
tain pieces of wood that have been found to be more than 
30,000 years old. These must have been included originally 
in older glacial deposits. 

Our theory may explain not only the earlier phases of the 
Wisconsin glaciation but also why most of their traces were 
destroyed. Let us assume that 50,000 years ago the previous 
crust displacement started shifting the pole from southern 
Greenland toward Hudson Bay. This would have started an 
expansion of glaciation in North America, with the ice mov- 
ing toward the west and south. We must visualize a gradual 
lowering of the temperature over a period of several thousand 
years, with those sudden changes resulting from volcanism 
with which we are already familiar. In this case, instead of 
each advance of the icecap falling short, at least in some 
places, of the preceding advances, so as to leave traces in the 
form of undisturbed moraines, the contrary happened. As the 
crust moved, the pole was steadily advancing from the north- 
east, and therefore each phase of expansion of the ice sheet 
would naturally carry the ice front farther than the one be- 
fore, plowing up and destroying the evidences of earlier 
phases, obliterating the record and incorporating the older 
glacial material with its own debris. Not until the climax of 
the glaciation was reached, with the Farmdale Advance, did 
a change in this situation occur. The date of this advance, 
therefore, may have been the time when the Hudson Bay 
region reached the pole and the crust ceased to move. 



</. Greenland at the Pole 

Several impressive lines of evidence are in accord with the 
assumption of the location of the general region of southern 
Greenland at the pole before the time when the Hudson Bay 
region may have been located there. In considering these 
lines of evidence, we shall assume that the period during 



EARLIER DISPLACEMENTS OF CRUST 289 

which Greenland was at the pole was of the order of 30,000 
or 40,000 years, or that it was roughly comparable in length 
to the period when Hudson Bay lay at the pole. This will 
carry us back, therefore, about 90,000 years. 

The assumption of a pole in southern Greenland seems 
able to solve a remarkable number of climatic problems per- 
taining to various parts of the world. In the first place, it can 
explain the evidence that indicates that the glacial period in 
Europe began earlier than the Wisconsin glaciation. It is 
consistent with the existence in New York State of the tem- 
perate fauna and flora which we saw were enclosed in the 
Wisconsin ice sheet. It would explain, as nothing else has 
explained, why the massive European ice sheet advanced 
southward only as far as the 5oth parallel of latitude, while 
in North America the Wisconsin icecap extended southward 
to the 4oth. A glance at the globe will be sufficient to show 
the reader the truth of this. In addition, this position of the 
pole will explain two different problems in Antarctica. On 
the om .and, in many parts of Antarctica, as already men- 
tioned, there are glacial striations above the present level of 
the ice, indicating that a thicker ice sheet once existed in 
those areas; on the other hand, the Ross Sea core N 4 (see 
Figure XI, p. 306) indicates temperate-type sediment on the 
bottom of the Ross Sea from about 65,000 to about 80,000 
years ago. Now this continuous deposition of temperate sedi- 
ment on the bottom of the Ross Sea for nearly 20,000 years 
is very difficult to explain. It quite obviously cannot be ex- 
plained at all in terms of the present position of the pole. 

If the reader will turn to the map of Antarctica (p. 276) on 
which I have indicated the various positions of the South 
Pole corresponding to our Hudson Bay, Greenland, and 
Alaskan North Poles, he will note that a South Pole corre- 
sponding to our Greenland North Pole would imply a 
thicker ice sheet than now in some parts of Antarctica. So 
far as the Ross Sea is concerned, an interesting situation 
emerges. It seems probable that the side of the Ross Sea near- 
est this former South Pole would be glacial, while the other 



290 EARTH'S SHIFTING CRUST 

side may have been nonglacial. Thus sediment of both kinds 
could be deposited in different parts of the Ross Sea at the 
same time, depending, perhaps, to some extent, on the local 
peculiarities of bottom topography and bottom currents. It 
cannot be assumed, of course, that the outlines of the conti- 
nent, or the depths of the surrounding oceans, were the same 
at that time as they are now. However, those who may still 
be inclined to discount the theory presented in this book 
must be reminded that all the phenomena discussed in this 
chapter and all the principal phenomena discussed in this 
book have been hitherto unexplained. It is not a question 
of choosing between explanations. There is, at the present 
time, no other explanation than ours of these facts. 

a. Cores from the San Augustin Plains 

A good deal of evidence from other cores supports this suc- 
cession of polar positions in Greenland and Hudson Bay. 
Let us consider first a very interesting study recently made in 
New Mexico. There a group of scientists have been studying 
a very long sedimentary core taken from the San Augustin 
Plains. On these plains, sediments have accumulated to a 
great depth without consolidating into rock, so it has been 
possible to bore down about 645 feet and get a cross section 
of all the deposits to that depth. These sediments contain 
pollen of various trees and plants, which, as is well known, 
does not easily disintegrate, but remains preserved in the soil 
for very long periods. In this core, different kinds of pollen 
in the different layers indicated changes in the species of trees 
and plants growing in the region, and of course changes in 
the kinds of plants growing in a region indicate changes of 
climate. For the upper and most recent part of the core, it 
was possible to use the radiocarbon method to date the 
changes in pollen types, and therefore in climate. 

Figure VIII (opposite page), prepared by Drs. Clisby and 
Sears (84), shows the climatic curve for the upper 330 feet 
of the core. The radiocarbon date at 27,000 years ago plus 



POLLEN PERCENTAGE 



SAND > 



10 20 30 40 50 60 70 80 90 100 



4-19,000* 1,600 

, 00 * 5,000- 3,200 




K DESERT 

I- V CHENOPODIACEAE 



Fig. VIII. Pollen Profile from the San Augustin Plains, New Mexico 



EARTH'S SHIFTING CRUST 

5,000 or minus 3,200 years (an unusually large margin of 
error) indicates glacial conditions at that time, and a rough 
extrapolation based on the rate of sedimentation indicated 
for the dated part of the core would indicate that glacial con- 
ditions began in New Mexico not more than about 40,000 
years ago. A most remarkable thing about this core is that it 
indicates temperate conditions from this point all the way 
down to the bottom. When it is considered that the older sec- 
tion dated by radiocarbon, about 27,000 years old, was only 
28 feet down in the core, it is evident that the core covers a 
very long time. 

This climatic record has some very important implications 
for us. It appears to show, for one thing, that the glacial 
period in North America generally did not extend back as far 
as the glacial period appears to have done in the North At- 
lantic and in Europe. It seems to show, unmistakably, that 
the so-called Sangamon Interglacial continued without a 
break, down to about 40,000 years ago, at least in western 
North America. Thus, it implies that the Sangamon Inter- 
glacial in North America was contemporary with the earlier 
part of the Wiirm glaciation in Europe. This is a remarkable 
state of affairs, and appears to dispose irrevocably of the doc- 
trine of the simultaneousness of glaciations. Incidentally, it 
provides confirmation of climatic conditions in New York 
State suitable for the mastodons and other animals that lived 
there before the growth of the Wisconsin icecap. It is there- 
fore in agreement with our assumption of a pole in southern 
Greenland. This core, the data considered above from North 
America and the Arctic, and the Antarctic cores give us a tri- 
angulation that provides extraordinarily strong confirmation 
of the theory. 

There is one factor, however, that may enter into the inter- 
pretation of this San Augustin core, which could invalidate our 
conclusions. The plains are now at an elevation of 7,000 feet 
above sea level. The earlier chapters of this book have ex- 
plained how displacements of the earth's crust may cause 
major changes in land elevations. A change in land elevation 



EARLIER DISPLACEMENTS OF CRUST 2Q3 

would, of course, affect the climate and therefore the vegeta- 
tion growing in an area. It is generally considered that 1,000 
feet in elevation is the equivalent of about eight hundred 
miles in latitude, so far as plant habitats are concerned. We 
therefore have to take into consideration the possible effect 
of an uplift of the plains during the time that the sediments 
were accumulating. In view of the fact that the 645 feet of 
sediments may easily embrace a total period of time exceed- 
ing a million years, or the length of the whole Pleistocene 
Epoch, and since we have evidence that there were a number 
of ice ages in North America during the Pleistocene, before 
the Wisconsin glaciation, we may be forced to assume that 
there was a considerable uplift of the plains during the 
Pleistocene. However, it is reasonable to suppose that during 
the comparatively short period we are now discussing the 
period from about 40,000 to about 90,000 years ago the up- 
lift may not have been of major proportions. 

Our Greenland pole is supported by other lines of evi- 
dence. In evaluating them, however, we shall have to take 
into consideration the still earlier hypothetical position of 
Alaska at the pole. 

b. Some North Atlantic Cores 

A number of cores have been taken in the North Atlantic, 
and dated by the new methods of absolute dating. Despite 
the fact that these cores were obtained independently by 
different scientists, and dated by different methods, we shall 
find that they agree well, and that they support our basic 
assumptions. 

The cores to be considered include three taken from the 
North Atlantic in about Lat. 46-49 N., and dated by the 
ionium method, and three cores from the Caribbean and 
the Equatorial Atlantic. 

The last three cores were prepared by Ericson, who ana- 
lyzed their enclosed foraminiferal remains for evidence of 
climatic change. They were subjected to radiocarbon tests by 



294 EARTH'S SHIFTING CRUST 

the United States Geological Survey. They were also studied 
by Dr. Cesare Emiliani, who used a technique developed by 
Dr. Harold C. Urey for determining ancient water tempera- 
tures. This technique makes use of an isotope of oxygen 
(Oi 8 ) the proportion of which in sea water is affected by 
temperature. The temperature of the water at which ancient 
shells grew (or, in this case, at which foraminiferal micro- 
organisms grew) can be determined by the proportion of 
Ois in the remains. This determination is independent of 
time, and the temperature at which a shell grew 200,000,000 
years ago (but not the date) can be determined just as well 
as if the shell grew last year. Emiliani used this technique to 
establish temperature curves for the sedimentary cores for 
the period within the range of radiocarbon. Then, using this 
as a base, he extrapolated to the older parts of the cores. 
There is reasonably good agreement between temperature 
curves arrived at in this way and those obtained by the 
ionium method. 

Of the three cores taken from the North Atlantic and 
dated by the ionium method, one extends back to only 1 1,800 
years ago, one to 24,300, and one to 72,500. The longest core 
will have the greatest interest for us (Figure IX). 

Core P- 12 6(5) was taken in mid- Atlantic, approximately at 
the latitude of Nova Scotia, in about three miles of water. 
Since it extends back to 72,500 years ago, it should be able 
to throw some light on the question of our assumed polar 
positions, including the Alaskan. 

The story of this core, as we recede into the past, is as 
follows: There is first a layer of volcanic glass shards, dated 
about 12,800 years ago, then a layer of nonglacial sediment, 
then glacial sediment from 14,700 to 23,700 years ago, then 
nonglacial sediment but with evidence of cold water, back 
to 60,700 years ago. This period of cold water is interrupted 
by three brief intervals of glacial deposition, by two layers of 
confused ("anomalous") sediments, and by a layer of volcanic 
glass shards between 51,400 and 55,400 years ago. Then, be- 
tween 60,700 and 68,000 years ago, the North Atlantic water 



EARLIER DISPLACEMENTS OF CRUST 

P-130 (9) 



P-124 C3) 



P-126 (5) 




300 



800 



NAUTICAL MILES 



Fig. IX. Chronology of Sediments in the North Atlantic Cores P- 124(3), 
P-i*6( 5 ), P-iso(9) 

gets warmer, until it becomes definitely warmer than it is 
today. The warm period continues to the bottom of the core. 
This core raises some enormously interesting questions. 
In the first place, it indicates very cold conditions, much 
colder than the present, in the North Atlantic back to about 
62,000 years ago, and we must ask, How can this be recon- 
ciled with the indications of a climate like the present on 
the San Augustin Plains for the same period? We shall see 
that the other cores, from the Caribbean and the Equatorial 
Atlantic, will intensify this contradiction, for they confirm 
the cold climate in the Atlantic. These cores constitute evi- 
dence for a pole in the Greenland region. 



296 EARTH'S SHIFTING CRUST 

A second vital question raised by the core is the existence 
of a warm North Atlantic 70,000 years ago: the foraminiferal 
studies made in connection with this core show that the 
North Atlantic was warmer then than now. There has been 
no explanation of this, yet obviously it is enormously im- 
portant. It may be explained by a polar position in the 
Alaskan region. We will return to this question in connec- 
tion with the other evidences for the location at that time 
of Alaska at the pole. 

Deposits of volcanic glass shards are not, from our point of 
view, something to be passed over without remark, especially 
when, as in this case, the deposits relate themselves remark- 
ably well to critical phases of our assumed crust displace- 
ments. The last such deposit agrees in time with the Gary 
Advance of the Wisconsin ice sheet, and may be considered 
as possible evidence of the intense volcanism that may have 
accompanied and, indeed, caused that glacial advance. The 
older band of volcanic shards also apparently coincides with 
a time of great change, as indicated by the Arctic cores al- 
ready discussed. That was the time when, according to our 
theory, the displacement started that was to shift Greenland 
from, and Hudson Bay to, the pole. 

It appears to me that the dating of the brief intervals of 
glacial deposition also has significance. For example, a brief 
interval of glacial deposition between 50,000 and 51,200 
years ago immediately follows the deposition of volcanic glass 
shards, which according to our theory can have represented a 
period of massive volcanism, which may have acted as the 
direct cause of the glacial advance, which, in turn, may have 
led to the deposition of the glacial sediment in the sea. Of 
course the finding of volcanic debris and glacial sediment in 
sequence in the same core is an accident in one sense, for a 
prolonged episode of massive volcanism anywhere else on 
the surface of the earth would have produced the advance of 
glaciers adjacent to the Atlantic. During any movement of 
the crust, we may assume that volcanism would be very active 
in many parts of the earth, and not necessarily in the immedi- 



EARLIER DISPLACEMENTS OF CRUST 2Q7 

ate neighborhoods of the ice sheets. The oldest episode of 
glacial deposition, about 60,000 years ago, coincides closely 
with the time that we have assigned hypothetically for the 
maximum of the Greenland glaciation. 

A serious problem is presented by the fact that the sedi- 
ment deposited in the North Atlantic during the period from 
23,700 to about 60,000 years ago is not actually glacial except 
for brief episodes. How can this be accounted for if we are 
to assume a pole in Greenland? For that matter, how can it 
be accounted for if we are to extend the Wurm glaciation in 
Europe back as far as the European geologists seem to de- 
mand? 

It is obvious, from the brief recurrent episodes of glacial 
deposition, that somewhere an ice sheet or ice sheets lay near 
the coasts, so situated that when expanded in the brief 
periods of greater cold brought on by massive volcanism, one 
or more ice sheets reached the sea. It may be necessary to 
consider that the pole in Greenland may not have been very 
near the sea at that time, and, as I have already suggested, a 
number of authorities are now receptive to the idea of a land 
connection across the North Atlantic. 

c. A North Atlantic Land Mass? 

This, in turn, produces another problem. If there was a land 
connection across the North Atlantic, and if the pole was in 
southern Greenland, would not the continental ice sheet 
have entered the British Isles from the northwest, instead 
of from the northeast, from the direction of Scandinavia? 
Strangely enough, a very persuasive book has been written 
by Forrest (164) to sustain precisely this thesis. I have spent 
considerable time checking his sources. I have gone through 
many of the original reports he used, including numerous 
field reports published by the British Association for the 
Advancement of Science, the Liverpool Geological Society, 
and other British geological societies. I have also checked 
secondary works by various British geologists. As a result I 



298 EARTH'S SHIFTING CRUST 

have found an impressive mass of reliable direct field ob- 
servation indicating that the original direction of the ice 
invasion of the British Isles, in the earlier part of the ice age, 
was from the northwest. In most areas the evidences of the 
movement were later overlaid or destroyed by the Scandi- 
navian ice sheet, or by local glaciers. 

In reviewing the field reports, and later the general geolog- 
ical works that used the reports as source material, I have 
noticed a most interesting phenomenon. Field observers 
quite often remarked on the northwest-southeast directions 
of certain glacial striations, on associated glacial evidences 
showing clearly that the ice moved from the northwest 
toward the southeast, and on evidence that the ice sheet 
swept over the tops of most of the mountains of Ireland, 
Wales, and Scotland, often across the axes of the valleys, and 
from the northwest. But as the discussion of the subject was 
removed from direct contact with the field, and as the field 
reports were condensed, abstracted, and interpreted, this evi- 
dence of ice movement from the northwest became more and 
more subordinated, and, finally, was lost to view. The reason 
for this is quite simple. The geologists were firmly convinced 
that the ice sheet could have come only from Scandinavia. 
An ice center in the North Atlantic, involving former land 
areas in that region, was quite unthinkable. This was a 
natural consequence of the general acceptance of the theory 
of the permanence of continents. Various ingenious solutions 
of the problem were suggested. Charlesworth pointed out that 
a westward-trending valley could turn an ice sheet descend- 
ing from the British highlands westward, and it might fan 
out on the coastal plain, so that its northern flank would actu- 
ally be moving toward the northwest. Other geologists have 
stressed glaciers expanding in all directions from elevated 
areas in Britain. The awkward thing is that precisely what 
these people assert happened probably did happen, but in 
the later part of the ice age, when the North Atlantic ice 
center was gone, the Scandinavian glacier lay along the east 
coast of Britain, and local valley glaciers occupied the in- 



EARLIER DISPLACEMENTS OF CRUST 

terior. Nobody, however, has properly examined the data 
cited by Forrest as his principal line of evidence. 

Recently Kolbe and Malaise have produced evidence that 
may cause many to turn to the work of Forrest with new 
interest. From the evidence of fresh-water diatoms indicating 
a former fresh-water lake on the mid-Atlantic ridge, now 
about two miles below the surface of the ocean, and from the 
study of the differing sediments deposited on the two sides 
of the ridge, Malaise reaches the conclusion that the mid- 
Atlantic range was above sea level until the end of the Pleis- 
tocene (2gia:207). 

Unfortunately, limitations of space must prevent further 
discussion of this question. I can only refer the reader to the 
works cited and to Forrest's original sources. Forrest has 
made a few mistakes in discussing matters dealing with ice 
sheets, but he himself calls attention to the fact that he was 
trained as a zoologist, not a geologist. However, his errors are 
not such as to affect the validity of his argument. The prin- 
cipal weakness of his book is that he does not present the 
evidence in sufficient detail, so that it is necessary to refer to 
the original sources. 

It is possible that the displacement of the crust that re- 
sulted in the movement of the pole from Alaska to Green- 
land may itself have raised the North Atlantic bpttom enough 
to bring a transatlantic land connection, in the manner sug- 
gested in Chapter IV, and that in consequence the Greenland 
ice sheet may have travelled along the land bridge into 
Britain. The subsequent displacement that shifted the pole 
toward Hudson Bay could have brought about the resub- 
mergence of parts of the land bridge, and have resulted in the 
destruction of the Greenland continental glacier. The final 
movement of the pole to its present location could have re- 
sulted in the submergence of the remnants of the land bridge. 

The advantage of our hypothesis is that it seems able to 
suggest both the cause of the creation of a land connection 
across the North Atlantic, and the cause of its disappearance. 
The fact that we have here two successive displacements of 



joo EARTH'S SHIFTING CRUST 

the crust helps us to account for the total amount of the 
submergence. Each of these hypothetical movements would 
have shifted the North Atlantic nearer the equator, and 
therefore, according to the theory, would have favored sub- 
sidence of land area relatively to sea level. The evidence of 
very widespread volcanism in the whole basin of the North 
Atlantic during the ice age (174) carries the implication, 
also, that invasion of the lower parts of the crust by molten 
magma of high density could have weighted and depressed 
the area, in the manner suggested earlier (Chapter VI). 

d. Additional Atlantic Cores 

To return to our Atlantic cores, a rather interesting point 
about Core P~i26(5) is that the deposition of glacial sedi- 
ment ceased about 14,000 years ago. It may be noticed, how- 
ever, that in another of the Urry cores, P-i3o(g), which was 
taken much farther to the east, the deposition of glacial sedi- 
ment ceased 1 8,000 years ago. One might at first be inclined 
to pass this over as an unimportant detail, until one realized 
that with Hudson Bay at the pole the difference is com- 
pletely explained. Under those circumstances, the second 
core, which now lies to the east, would have been due south 
of the first core, and it would be entirely natural that the 
warming of the climate at the end of the ice age would be 
felt first in the more southerly region. This, then, constitutes 
additional evidence for the location of the Hudson Bay 
region at the pole during the period of the Wisconsin glacia- 
tion. 

We have still to consider the Ericson-Suess-Emiliani At- 
lantic cores. I reproduce, below, Suess's graph of the tempera- 
ture changes in the Atlantic for the last 100,000 years, as 
evidenced by these cores. 

Now, to begin with, we note that according to these cores 
the temperature of the Atlantic Ocean was at a peak between 
75,000 and about 98,000 years ago; this agrees substantially 
with the Urry core already discussed, but extends the warm 



EARLIER DISPLACEMENTS OF CRUST 




40 50 

1000 YEARS - 



60 



70 



eo 



90 



Fig. X. North Atlantic Cores A 172-6, A 199-4, A 180-75 

period back to about 100,000 years ago. We will assume that 
this warm phase in the Atlantic represents the period, or at 
least the latter part of the period, when Alaska was at the 
pole. 

We note, too, that the temperature in the Atlantic during 
this warm period was not, at the sites of these cores, as high 
as the temperatures now prevailing there, except for two 
very brief spurts in Cores A 180-75 and A 179-4. Yet we 
have seen that the Urry core P- 12 6(5) indicated clearly that 
the water was warmer at that time than it is at present. How 
is this conflict to be solved? Shall we be forced to discredit 
the reliability of one finding or the other? Not at all. Our 
theory offers the possibility of eliminating this apparent con- 
tradiction in the evidence. 

Let us consider the present and past latitudes of these 
cores. P-i26(5) was taken in about the latitude of St. John's, 
Newfoundland; the others were taken in very low latitudes. 



EARTH'S SHIFTING CRUST 

If we assume that Alaska was at the pole during this warm 
period in the Atlantic, the site of this core would then have 
been farther from the pole than it is now; that is, it would 
have been south of its present latitude. Quite naturally the 
water would have been warmer. A glance at the globe will 
suffice to make this plain. 

On the other hand, if we now consider Core A 180-75, 
taken in the eastern Equatorial Atlantic, nearly on the 
equator, the opposite situation is revealed. A pole in Alaska 
would displace this core southward from the equator, pos- 
sibly as far as the 2Oth parallel of South Latitude (depending, 
of course, on the precise location of the pole in Alaska). 
Quite probably, the water would be colder then than it is at 
present, other things being equal. 

The two Caribbean cores would, with the Alaskan pole, 
have had approximately the same latitude as at present; the 
uncertainty as to the precise location of that pole makes it 
impossible to draw any reliable conclusions from them. 

Both the Caribbean cores indicate a temperature mini- 
mum about 55,000 years ago, which would correspond well 
with the date we have tentatively assigned for the arrival of 
Greenland at the pole; they both show the temporary warm 
period that was shown in the Arctic cores, which we have 
interpreted as marking the breakup of the Greenland conti- 
nental icecap. They then show a gradual temperature decline 
from about 40,000 to about 1 1,000 years ago, which may cor- 
respond, first, to the growth of the Wisconsin continental 
icecap and, finally, to the movement of the ice center of that 
icecap eastward into Labrador during the declining phases of 
the glaciation. 

At this point it is important to consider a contradiction 
between the Caribbean cores and the core from the eastern 
Atlantic. It appears that the ocean temperature reached its 
minimum, after the early warm period, in the eastern At- 
lantic about 20,000 years before it did in the Caribbean. 
This is a very important difference. How is it to be ex- 
plained? 



EARLIER DISPLACEMENTS OF CRUST 

It appears that this anomalous fact may constitute, in it- 
self, one of the most impressive confirmations of the whole 
theory of displacements of the crust, for, if you look at a 
globe and visualize the shift of the crust that moved Alaska 
from, and Greenland to, the pole, and if you use a tape 
measure to measure the distances from each polar position 
to the Caribbean and to the equator off the bulge of Africa, 
you will see that that particular polar shift should make only 
a comparatively slight change in the latitude of the Carib- 
bean, but a very radical change indeed in the latitude of the 
eastern Equatorial Atlantic. And since the movement would 
take the same period of time in both cases, the rate of move- 
ment would necessarily be much more rapid in the eastern 
Atlantic, and this both agrees with and explains the core 
evidence. 



5. Alaska at the Pole 

We have already seen that the assumption of Alaska's posi- 
tion at the pole between about 80,000 and about 130,000 
years ago helps to solve a number of important problems. 
The idea for this position first occurred to me when I 
learned of the work of Arrhenius (i3a), who took cores 
from the North Pacific and found that there was a fall of 
temperature in that area about 100,000 years ago. He de- 
cided that that fall of temperature must have marked the 
beginning of the ice age everywhere. But as we have seen, 
the evidence shows that this "ice age" began at very different 
times in different areas. We are forced to develop a theory 
that will explain why the ice age developed in different areas 
at different times. 

I fully realize that this suggestion of one previous polar 
location before another in an apparently endless succession 
may cause some discomfort to the reader. He may be willing 
to settle for the Hudson Bay pole; after all, the evidence is 
rather overwhelming. The Greenland pole may be worth 



304 EARTH'S SHIFTING CRUST 

considering, because after all it at least makes sense of the 
radiocarbon datings and the Atlantic marine cores. But this 
Alaskan proposition is, he may think, going altogether too 
far. Where will we end? Is the whole history of the earth 
to be considered in terms of this hop, skip, and jump of the 
poles? And is it conceivable that this sort of thing could have 
kept up for two billion years? 

If the reader is having this sort of crisis of belief, I suggest 
that he consider the matter in this light: one shift of the 
crust, at the end of the ice age, has been pretty well demon- 
strated. Another one, at the beginning of the ice age, is neces- 
sarily and logically implied. The interval between them 
seems to have been about 40,000 years. Now if we accept one 
such unit, why not accept the previous ones also? After all, 
the laws of nature work continuously: that was the principle 
laid down by Sir Charles Lyell over a century ago. It is ob- 
viously sensible to work from the known to the unknown: 
if we are fairly sure that the crust did move once or twice, 
and at a certain rate, then it is but a jump to accepting with- 
out a qualm a thousand such movements in the long history 
of the globe. 

The further advantages inherent in the assumption of the 
Alaskan pole, and the general evidence for it, may be briefly 
summarized. It explains the cause of the warm Interglacial 
Period in Europe, when lions and hippopotamuses and ele- 
phants romped around in Britain and on the Continent (to 
which Britain was then probably joined). It allows for the 
Sangamon Interglacial in the eastern parts of the United 
States and Canada. As between the two polar positions, in 
Greenland and Alaska, we have an explanation of the length 
of the Sangamon Interglacial. We may visualize it as a warm 
period that began and ended at different times in different 
parts of North America, and that was warmer in given areas 
at certain times than at others. The speed of climatic changes 
was slow enough to permit the gradual migration and adapta- 
tion of species, and yet there were also abrupt, disastrous 
changes due to the effects of volcanism, which, as we have 



EARLIER DISPLACEMENTS OF CRUST 305 

seen, could account for the widespread Pleistocene extinc- 
tions. 

Speaking of more specific evidences, if the Alaskan Penin- 
sula were near the North Pole, this would have meant the 
deglaciation of the Ross Sea and, indeed, of all that half of 
Antarctica. What have the Ross Sea cores (Figure XI) to 
say? Core N-4 shows deposition of nonglacial sediment from 
110,000 to 130,000 years ago. This by itself provides some 
confirmation. Core N-5 shows deposition of nonglacial sedi- 
ment from 130,000 to 180,000 years ago, implying that either 
the pole was situated in Alaska for a long time or else a still 
earlier polar position was so situated as to give Antarctica 
temperate conditions. Core N-g shows fine glacial sediment 
from about 120,000 to about 200,000 years ago. This, too, 
implies a climate warmer than the present, but the evidence 
is, obviously, inconclusive. Only a great many more cores 
from the same area can clarify these ambiguities. 

As I have mentioned, with each step backward into the 
past, the evidence decreases geometrically in quantity. The 
available indications of a pole in Alaska amount to no more 
than suggestions for research, but, in my opinion, they can- 
not be disregarded on that account. It might be objected 
that if Alaska was at the pole only 100,000 years ago, there 
should be plentiful evidence of a continental glaciation in 
Alaska. We must not be too easily impressed by this objec- 
tion. In the first place, there is a possibility that many of the 
evidences have been destroyed since that time by the glaciers 
of the Wisconsin period, and by the present glaciers. Then, 
there is the obvious possibility that evidences have been over- 
looked or misinterpreted, as seems to have occurred in Brit- 
ain. Finally, if widespread subsidence of land areas has oc- 
curred in the North Atlantic, so may it have occurred in the 
Pacific. Extensive evidence of a North Pacific land bridge 
(not to be confused with a Behring Strait connection) has 
been summarized by Dodson (115:373). How long Dodson's 
land connection may have lasted is not known, but it could 
conceivably have lasted until comparatively recent times. 



306 



EARTH'S SHIFTING CRUST 



CORRELATION IN YEARS TOUT'S 8' I? 1 8 
IURRY) ;tV)M 37-JOM 


Q* 8'S 






soo -. 

1 000 ' 


&&* ilj^ji 


; %r- 

II 




SYMBOL -TYPE OP SXOIMINT 


w 


8 000 








p^A^ COARSE OLACIAL MARINE 
pj^g MEDIUM OLACIAL MAWNC 




LATt 
WISCONSIN 

INTERLACIAL 

SANOAMON 
WTCRLAOAL 


10000 

JO 000 
30000 ' 
40000 -i 

so ooo 

100000 


* 






I I FINE OLACIAL MARINC 

EH 'awAaraTa. 

n r ^uo 4w " WILL - 

M LAMINATED PlNC OUINEO 
WELL SORTED 


m- 


I 


I" " ^ 


Is 


LITHOLOOY BY J.L.HOU6N 


ILLINOIAM 

YARMOUTH 
INTER OLACIAL 


oooo,o ~ 

300 000 - 
400000 - 


.. 






ACE DETERMINATIONS BY 
W.O.URRY, USINO PCX CENT OP 
EQUILIBRIUM METHOD POM URANIUM 
lOUUM AND RADIUM. ACES GREATER 
THAN 300.000 YEARS BY EX- 


" 


fp 

:'!'. /.. ' 








SOO 000 - 
















n^riim 
'"'i? 1 ' ', 








00000 - 










K A II SAN 


- 












700000 - 




li 






AFTON1AN 
INTEMLAOAL 


00000 - 




S^ 






MEMASKAN 


- 




S- 








00 000 - 
1000000 - 




I 







Fig. XI. Lithology of Core Samples, Ross Sea, Antarctica 



EARLIER DISPLACEMENTS OF CRUST 307 

A small amount of additional evidence for our assumed 
sequence of climates in Alaska has come to light. Our assump- 
tions call for a frigid climate in Alaska down to about 75,000 
years ago, with a warming of the climate coinciding with the 
refrigeration of the Atlantic as the polar position migrated 
to Greenland. Then, about 25,000 or 30,000 years ago, the 
climate was refrigerated (later than in eastern North Amer- 
ica) as a consequence of the advance of the Wisconsin ice 
sheet. 

Karlstrom (247) has shown through radiocarbon dating 
that the oldest glacial stage of the Wisconsin glacial period 
in Alaska began not earlier than the Farmdale Advance in 
Ohio, 25,000 years ago, and not later than 19,000 years ago. 
This is in accord with our supposition that the glacial cli- 
mate advanced from the east. Before this Alaskan glacial 
stage, Karlstrom has an interglacial extending back an un- 
certain distance. This, obviously, is, in terms of current 
theory, in disaccord with the contemporary climatic trends 
in the Atlantic. Before the interglacial period Karlstrom 
notes evidence of a glaciation that he considers to be pre- 
Wisconsin but post-Illinoisan. Since this glaciation was be- 
yond the range of the radiocarbon method, he had to depend 
upon the assumption of climatic control by the solar insola- 
tion curve in order to estimate its date. He estimates that 
this older glaciation was at least 47,000 but not more than 
87,000 years ago. Presumably these dates mark the estimated 
time of the end of the glaciation. Even though his basis of 
calculation may not seem acceptable (for reasons already dis- 
cussed), it is plain that his date is in pretty good accord with 
our date for the Alaskan pole. No doubt it is based in part 
on a lot of stratigraphic studies that prove the antiquity of 
the glaciation, and at the same time show that it is younger 
than the Illinoisan ice age. 

This climatic reconstruction throws an interesting light on 
a forgotten item of paleontological research that I chanced 
upon in the Smithsonian Miscellaneous Collections for 1913. 
It was entitled "Notice of the Occurrence of a Pleistocene 



308 EARTH'S SHIFTING CRUST 

Camel North of the Arctic Circle/' The author, James Wil- 
liam Gidley, described the discovery in Alaska not only of 
the camel remains but also of the remains of elephant and 
of other animals, including the horse and bison. He then 
remarks that the discovery "adds proof in support of the sup- 
position that milder climatic conditions prevailed in Alaska 
during probably the greater part of the Pleistocene period" 
(173:1). We do not have to go all the way with Mr. Gidley. 
But here indeed is evidence enough of the existence of 
really temperate conditions very possibly in the very period 
of time when the assumption of the Greenland pole calls for 
them. A final consideration relating to the evidence for a 
pole in Alaska is that this could have caused the Cordilleran 
glaciation, which, according to Coleman, preceded the Lab- 
rador and Keewatin ice sheets (87:10). It may be added also 
that there is real support from fossil terrestrial magnetism 
for the polar succession in Alaska and Greenland. The Jap- 
anese geophysicist Akimoto and his colleagues have produced 
magnetic evidence of the migration of the pole from north 
of North Central Siberia, in the Arctic Ocean, across Alaska 
to Greenland in the Pleistocene (418:11). 

Thus the matter must be left, for the present. If it seems 
to the reader that I have sometimes based too much on too 
little data, and that I sometimes attribute too much signifi- 
cance to isolated facts, I agree that I have probably commit- 
ted this error at times. On the other hand, there is sometimes 
a tendency to postpone any thinking, in the hope that the 
necessity of revising basic principles may be removed by 
additional facts. 



6. The Remoter Past 

Since, as I have mentioned, with every step backward into 
time the evidence becomes thinner, it is hardly worth while 
to attempt, at present, to solve the problem of the earlier 
positions of the poles that would be required to explain the 



EARLIER DISPLACEMENTS OF CRUST 309 

climatic history of the Pleistocene. Eventually, perhaps, this 
can be done. Much more practical questions remain to be 
considered. 

We must consider whether the rate of geological change 
suggested for the last 130,000 years, by the evidence pre- 
sented in this book, can be typical for the entire history of 
the earth. It is plain from the cores that rapid change has 
characterized the record for the Pleistocene. Radiocarbon 
dating has established the fact that all the geological processes 
of glacial growth and decay, precipitation and sedimentation, 
were enormously accelerated during the Wisconsin ice age. 
Emiliani has argued, as already mentioned, that all the ice 
ages of the Pleistocene occurred in the last 300,000 years, 
which implies a threefold increase in the velocity of geologi- 
cal change, as compared with the older views. Studies of the 
delta of the Mississippi River suggest numerous important 
changes at short intervals (165, 276, 349). Blanchard has 
shown that there were at least twelve major climatic changes 
in the valley of the Somme since the first glaciation, accom- 
panied by changes in sea levels, fauna and flora, and human 
cultures. As already mentioned, he argues that only polar 
change can explain this record (38). 

For the older geological periods, there are a number of 
lines of evidence that suggest rapid change. So insistently, 
indeed, does this theme occur in the strata that Brooks, in 
his Climate Through the Ages, refers to a 2i,ooo-year cycle 
of climatic change which he believes operated through the 
whole Eocene Period, or for about 15,000,000 years. His fig- 
ure, of course, is only a rough average, and the intervals may 
have been very unequal in length. With reference to a still 
older period he remarks, "Alternations in the Cretaceous 
of U.S.A. suggest a cycle that is estimated at 21,000 years, 
but there are no annual layers" (52:108). 

Irregularities in the cycle are indicated by another study 
of Eocene beds covering about 5,000,000 to 8,000,000 years. 
In this case annual varves were present, and they indicated 
long-term changes at 23,000 and 50,000 years (52:108). Some 



EARTH'S SHIFTING CRUST 

scientists have attempted to explain these cycles as the result 
of the earth's astronomical precession, but, in view of the 
above-mentioned irregularities, the phenomena seem better 
explained in terms of crust displacements. 

Naturally, such frequent changes in climate have had pro- 
found effects on the formation of sedimentary rocks, the 
chief consequence, perhaps, being the thinness of the indi- 
vidual strata. Very seldom can deposits be found that indi- 
cate with any certainty the uninterrupted deposition of more 
than a few thousand years. On the other hand, innumerable 
cases of conditions interrupted after a few thousand years 
can be proved. In addition to the evidence mentioned above, 
Brooks, for example, refers to a great salt lake or inland sea 
that existed in Europe in the Permian Period, and says: 

The number of annual layers indicates that the salt lake existed 
for some 10,000 years, after which the salt deposits were covered by a 
layer of desert sand (521*5). 

Wallace, too, refers to the evidence of sudden changes in 
climate at short intervals, in his Island Life: ". . . the 
numerous changes in the fossil remains from bed to bed only 
a few feet and sometimes a few inches apart" (446:204). 

Some of the best evidence is provided by coal seams, which 
are ordinarily thin and interlayered with rock indicating 
very different climatic conditions. There has developed a 
considerable literature on the rate of coal formation, and 
some recent experimentation has thrown light upon it. 

Croll devoted considerable attention to the problem. He 
estimated that it would take about 5,000 years for the forma- 
tion of one yard (or about a meter) of coal (91:429), and 
came to the conclusion that the periods of coal formation 
between changes in climate were about 10,000 years long. It 
is obvious that any changes that replaced conditions required 
for coal formation by conditions suitable for the formation 
of sedimentary deposits beneath the sea (for Croll points out 
that rock strata between the coal strata are usually of marine 
origin) (91:424) were indeed radical changes, taking place in 



EARLIER DISPLACEMENTS OF CRUST Jll 

short periods of time. Another writer, Otto Stutzer, after 
very careful calculation, concluded that a Pittsburgh coal 
bed seven feet thick could have been formed in no more 
than 2,100 years (407). 

In view of all this evidence, we must not be too much im- 
pressed by the very thick layers of rock that are occasionally 
found. Croll, who was a sound geologist, even if his theory 
about ice ages was not accepted, pointed out that 

. . . The thickness of a deposit will depend upon a great many 
circumstances, such as whether the deposition took place near to land 
or far away in the deep recesses of the ocean, whether it occurred at 
the mouth of a great river or along the sea-shore, or at a time when 
the sea-bottom was rising, subsiding or remaining stationary. Stratified 
formations 10,000 feet in thickness, for example, may under some 
conditions, have been formed in as many years, while under other 
conditions it may have required as many centuries (91:338). 

It is worth noting that at a number of points the evidence 
for great and frequent changes in the earth's climatic condi- 
tions is linked with evidence of structural changes in the 
earth's crust, that is, with changes in the elevation of lands, 
and in the distribution of land and sea. Croll remarked: 

... It is worthy of notice that the stratified beds between the coal 
seams are of marine and not of lacustrine origin. ... If, for example, 
there are six coal seams, one above another, this proves that the land 
must have been at least six times below and six times above sea-level 
(91:424). 

Coleman has emphasized the frequent association of 
abrupt breaks in the continuity of the strata with extreme 
changes of elevation above or below sea level. In discussing 
the Permo-Carboniferous period in India, he says: 

There are the usual cold climate fern leaves in these beds, and 
above them, without an apparent break, come the Productus lime- 
stones with marine fossils (87:102). 

Now, it seems altogether reasonable to suppose that if 
changes of climate were associated with changes of elevation 
in these different kinds of cases, then the two may have oc- 



EARTH'S SHIFTING CRUST 

curred at the same tempo, and have proceeded from the 
same cause. The hypothesis of periodical shifts of the earth's 
crust provides both the link and the cause. 

An interesting study of repeating geological cycles in a very 
remote period has been completed by Weller (451). He deals 
with the so-called "Pennsylvanian" period several hundred 
million years ago, which had a span of between 35 and 50 
million years. He points out that in the study of this period 
numerous examples have been observed of the deposition 
of different kinds of sedimentary beds in the same order, at 
irregular intervals of time. The changes in the composition 
of the beds imply changes both in climate and in the eleva- 
tion of the areas above sea level. The cycles are not just local, 
but can be traced over wide areas (451:110). Furthermore, 
each complete cycle represents an advance, retreat, and re- 
advance of the sea. Weller accounts for the cycles by dias- 
trophism that is, by some sort of upheaval in the earth, 
some activity within the earth's body but is not able to 
specify its nature. He recognizes about 42 cycles during the 
period, with each cycle having a duration of about 400,000 
years. 

These cycles would appear at first glance to be consider- 
ably longer than those that might result from crust displace- 
ments. However, there are a number of factors that tend to 
lessen the apparent difference between them. First, Weller 
points out that discontinuities in the deposits he is discussing 
are far more numerous than is generally supposed (451:99- 
101). This means that a part of the record is missing. Then, 
we must remember that a complete cycle, involving the re- 
treat and the advance of the sea (probably in a number of 
stages), would call for several, perhaps quite a few, move- 
ments of the crust. At any one point on the earth's surface, 
several movements might be required to bring the sea level 
to its lowest point, and several more to bring it to its highest 
point. We have already discussed this question (Chapter IV). 
Moreover, Weller points out that in each of his cycles deposi- 
tion has been interrupted two different times, thus reducing 



EARLIER DISPLACEMENTS OF CRUST 

the average length of the subdivisions of the cycle to periods 
of the order of 75,000 to 250,000 years. But it must be re- 
membered that we have only averages; the cycles differ 
greatly and their subdivisions also differ greatly in length. 
When we consider the fact that the intervals and directions 
of crust displacements are necessarily irregular, there appears 
to be a very good agreement between our theory and the 
facts of the Pennsylvanian cycles. At least, it will hardly be 
denied that the theory offers the first possibility of under- 
standing the cycles. Moreover, if our recent experience of the 
shortening of our estimates of geological time in the Pleisto- 
cene is a valid basis for extrapolating to earlier periods, it 
may well be that geologists have exaggerated the length of 
the Pennsylvanian Period, and that Weller has consequently 
attributed too great an average duration to his cycles. It 
appears, therefore, that crust displacements may have been 
occurring through the whole of one of the major subdivisions 
of the Paleozoic Era. 

It is impossible, however, in the present state of the evi- 
dence, to say that displacements of the crust have been going 
on uninterruptedly all through geological history. It may be 
that there have been times of quiet, when, for one reason or 
another, great icecaps failed to develop. The important thing 
at the moment is that investigators should be willing to un- 
dertake further inquiry without preconceptions based on 
outmoded ideas of gradual change. We may note a serious 
warning against this bias uttered by no less an authority than 
Sir Charles Lyell, the greatest geologist of the first half of the 
nineteenth century, and the father of gradualism in geology. 
In the course of a discussion of some evidence of recent fold- 
ing of rock strata on the Danish island of Moen, he remarked: 

It is impossible to behold such effects of reiterated earth move- 
ments, all of post-Tertiary date, without reflecting that, but for the 
accidental presence of the stratified drift, all of which might easily, 
where there has been so much denudation, have been lacking, even 
if it had once existed, we might have referred the verticality and 
flexures and faults of the rocks to an ancient period, such as the era 



314 EARTH'S SHIFTING CRUST 

between the chalk with flints and the Maestricht chalk, or to the 
time of the latter formation, or to the Eocene, or Miocene or older 
Pliocene eras. . . . Hence we may be permitted to suspect that in 
some other regions, where we have no such means at our command 
for testing the exact date of certain movements, the time of their oc- 
currence may be far more modern than we usually suppose (281: 
393-94)- 

And let us also recall the following words of the greatest geol- 
ogist of the second half of the nineteenth century, Eduard 
Suess: 

The enthusiasm with which the little polyp building up the coral 
reef, and the raindrop hollowing out the stone, have been contem- 
plated, has, I fear, introduced into the consideration of important 
questions concerning the history of the earth a certain element of 
geological quietism derived from the peaceable commonplaceness of 
everyday life an element which by no means contributes to a just 
conception of those phenomena which have been and still are of the 
first consequence in fashioning the face of the earth. 

The convulsions which have affected certain parts of the earth's 
crust, with a frequency far greater than was until recently supposed, 
show clearly enough how one-sided this point of view is. The earth- 
quakes of today are but faint reminiscences of those telluric move- 
ments to which the structure of almost every mountain range bears 
witness. Numerous examples of great mountain chains suggest by 
their structure the possibility, and even in some cases the probability, 
of the occasional intervention in the course of great geological eras 
of processes of episodal disturbances of such indescribable and over- 
whelming violence, that the imagination refuses to follow the under- 
standing and to complete the picture of which the outlines are 
furnished by observations of fact (408:!, 17-18). 

The great work from which the foregoing statement was 
taken is entitled The Face of the Earth. The prospect that 
unfolds before us, as we contemplate the possibility that total 
displacements of the earth's crust have been a feature of geo- 
logical history since the formation of the crust itself, is noth- 
ing less than the discovery of the formative force, of the 
shaping factor, that has been responsible not only for ice 
ages, not only for the mountain ranges, but even possibly for 
the very history of the continents, and for all the funda- 
mental features of the face of the earth. 



X : LIFE 



In the preceding chapters we have reviewed a mass of evi- 
dence that suggests displacements of the earth's crust, at 
comparatively short intervals, during the earth's history. We 
shall now see that this assumption throws some light on the 
process of evolution. 



/. The Cause of Evolution 

A century ago, in the Origin of Species, Darwin suggested 
natural selection as the mechanism to account for evolution. 
The combination of the occurrence of natural variations 
with elimination of the unfit individuals in the competitive 
struggle for existence helped to explain a process of un- 
ending, gradual change in the forms of life. Darwin did not 
consider that this was the whole answer. He admitted, for 
example, that he could not explain the numerous instances 
of the world-wide extinction of many forms of life simultane- 
ously, especially in those cases where, apparently, there were 
no competitors and no successors to the extinct forms. Biolo- 
gists today are in agreement that evolution has occurred, but 
they also feel that the process has not been satisfactorily ex- 
plained. Thus Dr. Barghoorn, of Harvard, has recently re- 
ferred to "our limited understanding of the actual causes of 
evolution," while quoting Dr. George Gaylord Simpson, 
author of the widely read Meaning of Evolution, as remark- 
ing, ". . . search for the cause of evolution has been aban- 
doned" (375:238). There is a tendency at the present time 
for specialists to recognize a large number of interacting fac- 
tors that may, together, conceivably account for evolution, 
though their relative importance is not agreed upon. This 
situation does not exclude the possibility that the confusion 



316 EARTH'S SHIFTING CRUST 

may, indeed, arise because one factor is still missing: a factor 
which, when added, will bring the others into proper focus. 



2. The Problem of Time 

While no biologists since Darwin's time have questioned the 
basic fact of evolution, numerous difficulties have developed 
with natural selection. In the first place, while Darwin could 
present evidence of changes produced in varieties of plants 
and animals by artificial selective breeding, he was not able 
to show how, even under artificial conditions, such changes 
could lead to the establishment of new species. Recently, 
some progress may have been made in solving this problem, 
but by the end of the nineteenth century, Darwin's explana- 
tion of the mechanism of evolution had been largely aban- 
doned. Natural selection had come to be considered, by 
many biologists, as chiefly a negative factor, capable of elimi- 
nating unadapted variations but not of producing new 
species. 

Around the turn of the century the attention of evolution- 
ists was turned to mutation, the sudden change in hereditary 
characteristics produced by an alteration of the basic genetic 
factors, genes and chromosomes. One of the early mutation- 
ists, Hugo de Vries, believed that a large-scale mutation 
might produce a new kind of plant or animal in a single 
step (115:96). Many evolutionists then adopted mutation, 
and gave up natural selection as the explanation of evolution. 

This did not, however, end the controversy. A neo-Dar- 
winian school, clinging to natural selection, raised damaging 
objections to the theory of evolution through massive muta- 
tions. They insisted, for one thing, that different plants or 
animals differed by a great many minor traits, rather than 
by a few major ones. This would mean that a great many 
mutations would be required, and that these mutations 
would have to take place in the same individual, or in the 
same line of descent. The fact that mutation is apparently 



LIFE 317 

an entirely accidental process rendered the mathematical 
chances against the coincidence of many mutations in one 
individual or in one line o individuals completely over- 
whelming. 

But this was by no means the only difficulty. The anti- 
mutationists could argue that since mutations were purely 
accidental changes in the hereditary factors, and did not 
occur in response to needs created by the environment, most 
mutations would be positively harmful, or at least negative, 
and would have no effect on the adaptation of the organism 
to its environment. Only a chance mutation now and then 
could help an organism to survive. Mutationists were unable 
to show the existence of any principle by which mutations 
would be adaptive, that is, brought about as a part of an 
effort of an organism to adapt to the environment. Some 
recent experiments indicate that such adaptive mutation 
may occur, perhaps under special and rare conditions, but 
it still cannot be shown that adaptation by mutation has been 
an important factor in evolution. 

The mutationists did establish, of course, that minor muta- 
tions were of frequent occurrence, and might even be in- 
duced artificially; therefore, evolutionists accepted them, but 
they recognized them as just another way of accounting for 
the occurrence of variations. The law of natural selection 
would still be required, in order to eliminate the harmful 
mutations, which would constitute the great majority of all 
mutations. For a while it seemed that, in this way, the basic 
question of evolution was answered. 

It soon appeared that this was very far from being the 
case. The acceptance of mutations by the Darwinians as a 
factor in evolution did not solve the problem. It became 
clear, as time passed, that a major difficulty remained. Atten- 
tion was concentrated on the rate at which mutation and 
natural selection could be effective in changing life forms. 
Mathematical studies showed that such changes would take 
place, according to the theory, at rates so slow that even long 



318 EARTH'S SHIFTING CRUST 

geological eras would provide insufficient time for evolution. 
Professor Dodson wrote: 

In nature, neither mutation nor selection will ordinarily occur 
alone, and so the two will act simultaneously, perhaps in the same 
direction, perhaps in opposite directions. . . . Most frequently, selec- 
tion will work against mutation, as the majority of possible mutations 
are deleterious. This will result in very slow change, if any. . . . 
(115:298). 

He emphasized: 

It appears that it is extremely difficult for mild selection pressures, 
unaided by any other factor, to establish a new dominant gene in a 
species. . . . (115:298). 

By "mild selection pressure/' Dodson means those condi- 
tions of competition between life forms pointed out by Dar- 
win, that is, the competition that goes on at all times. What 
he suggests here is that some more drastic influence must 
have operated to produce evolutionary change. 

After discussing Haldane's mathematical calculations indi- 
cating the astronomical numbers of generations that might 
be required to change a plant or animal under the influence 
of mild selection pressures, Dodson quotes Dobzhansky (the 
leader of the neo-Darwinian school) on their implications: 

. . . The number of generations needed for the change may, how- 
ever, be so tremendous that the efficiency of selection alone as an 
evolutionary agent may be open to doubt, and this even if time on a 
geological scale is involved (115:298). 

Thus the problem is clearly posed: it is the problem of 
time. It is necessary to find some way of explaining how 
natural selection can have operated at a sufficiently rapid 
rate to account for evolution. A factor of acceleration is re- 
quired. 

Some writers, when they saw that evolution could not be 
explained even with the enormous amounts of time available 
under the current concepts of the lengths of the geological 
periods, felt compelled to revert to mystical explanations. 
Writers such as du Noiiy (119) concluded that evolution was 



LIFE 

totally inconceivable unless its course had been indicated in 
advance, by the reigning influence of cosmic purpose. For 
these writers, the end or final purpose of evolution must be 
the active controlling force of the whole process. The process, 
at basis, could be understood only as the direct effect and 
evidence of the will of God. 

Another solution was proposed by Richard Goldschmidt, 
who became the leader of the anti-Darwinians. He renewed 
the emphasis on major or macromutations. As Dodson 
puts it: 

. . . Goldschmidt believes that the neoDarwinian theory places 
too great a burden upon natural selection, and hence that the work 
of selection must be shortened by some other process, namely sys- 
tematic mutation (115:299). 

By "systematic mutation* ' is meant a mutation that changes 
not merely an individual trait of an organism but a whole 
complex of traits, that is, that changes a basic principle of 
the biological system. The great advantage of Goldschmidt's 
theory is that it may greatly reduce the number of "genes" 
required to account for the traits of a single individual. 
Under present concepts of genetics, for example, from 5,000 
to 15,000 "genes" may be called for to account for all the 
traits of the fruit fly, Drosophila melanogaster, while as many 
as 120,000 may be required for man (115:245). The gene it- 
self, of course, since it has never been identified under the 
microscope, and since its structure and mode of functioning 
are entirely unknown, must still be classified as a useful scien- 
tific assumption, rather than as a verified entity. The present 
state of gene theory is roughly analogous to the state of 
atomic theory before the development of subatomic physics. 
Then the atomic theory was accepted because it worked in 
practice, but nobody knew what an atom was. Today, we 
know only that some sort of unit like a gene seems necessary. 

The majority of writers on evolution today seem to feel 
that Goldschmidt's specific arguments for macromutations 
have been refuted. I can contribute no opinion on this tech- 
nical question. But, from my point of view, the most signifi- 



320 EARTH'S SHIFTING CRUST 

cant thing about the Goldschmidt theory is that he produced 
it in an effort to gain time for the process of evolution, to 
accelerate it, so that the amount of evolutionary change in 
life forms could be brought into rough agreement with the 
available amount of geological time. The rejection of his 
theory, if the rejection is indeed based upon sound considera- 
tions, means that another factor must be found to account 
for the tempo of evolution. 



3. Climate and Evolution 

Evolutionists, in general, agree that climatic change must 
have had a powerful influence on evolution. Geologists have, 
as I have pointed out, found a correspondence between 
periods of climatic change and changes in the forms of life. 
It is evident that as long as the general environment remains 
roughly the same, there can be only gentle selection pressures 
such as, apparently, are inadequate to account for evolution. 
With static environmental conditions, forms of life may con- 
tinue virtually unchanged for tens or hundreds of millions 
of years. There are any number of organisms living today 
whose very similar ancestors lived in remote geological 
periods. To name merely a few, there is the newly discovered 
coelacanth, a fish whose ancestors, one hundred or more 
million years ago, looked as he does today; the recently dis- 
covered Dawn Redwood, found growing in China, after hav- 
ing been regarded as extinct since its close relatives disap- 
peared in Alaska about 20,000,000 years ago; the sphenodon, 
a reptile of New Zealand, whose ancestors, very closely re- 
sembling himself, were contemporaries of Tyrannosaurus 
rex; horseshoe crabs, whose time span may amount to half a 
billion years; palm trees, whose age has just been "jumped" 
another 10,000,000 years (261); sharks; scorpions, and so on. 
Sanderson has pointed out that "living fossils" are simply too 
numerous to list (365). We can take it that, if external condi- 
tions are stable, or if animals and plants can migrate around 



LIFE 321 

to find the conditions they are used to, they may continue to 
exist indefinitely. 

At the same time, it is equally true that any kind of animal 
or plant may succumb, in the course of the usual and con- 
tinuous competition between life forms, and the local or 
transitory climatic variations that are always occurring. It 
would distort the picture to forget this fact. Furthermore, 
recent studies have shown that new varieties of plants and 
animals can appear within very short periods of time, on the 
order of a century or less, if they live in conditions of isola- 
tion (115:365). But these rapidly produced varieties are not 
the same, of course, as established species. 

A factor which, undeniably, must produce pressure for 
profound change in the forms of life is major climatic change. 
Clearly, this will apply what evolutionists call "strong selec- 
tion pressure." In this case life forms will have but three 
alternatives: to migrate, to adapt, or to die. Geologists and 
biologists have never denied the truth of this: Coleman, for 
example, recognized the importance of the glacial periods in 
"hastening and intensifying" the process of evolution (87:62). 
Lull recognizes the importance of basic climatic change, 
thus: 

. . . For changes of climate react directly upon plant life, and 
hence both directly and indirectly upon that of animals, while re- 
striction or amplification of habitat and the severance and formation 
of land-bridges provide the essential isolation, or by the introduction 
of new forms increase competition, both of which stimulate evolution- 
ary progress (278:84). 

The problem has been, until now, that major climatic 
changes, and concomitant changes in the distribution of land 
and sea, could not be explained by any acceptable theory. 
They were inexplicable events in themselves; their coinci- 
dence in time was inexplicable. Even more serious, they were 
assumed to have happened only at such extremely long inter- 
vals that the total number of such major climatic "revolu- 
tions" was too small to account for more than a very insig- 
nificant portion of evolutionary history. 



322 EARTH'S SHIFTING CRUST 

To recapitulate what has already been said, if drastic cli- 
matic and geographical change is the most obvious factor 
to which to look for changes in life forms, then it is to the 
acceleration of that factor that we must look for the accelera- 
tion of evolution. In the previous chapters we have been led 
again and again by the force of the evidence to the concept 
of displacements of the earth's crust. There is no reasonable 
doubt as to the effect that such displacements, at relatively 
short intervals, would have on the tempo of evolution. They 
could not fail enormously to accelerate the several aspects of 
the evolutionary process. Let us now examine some of these 
special aspects in more detail. 

Wright has pointed out that the rate of evolutionary 
change may have been accelerated at various times through 
the mass transformation of one kind of plant or animal into 
another (115:314). This requires that all over the area of 
distribution of the life form in question there must be strong 
pressure for change in the same direction. This means that 
similar new varieties would appear simultaneously and inde- 
pendently in countless localities or that well-adapted new 
varieties would spread and become established rapidly. Quite 
obviously this would tend to accelerate evolution. 

But how would such mass transformation be brought 
about? It could only result from profound transformation of 
the environment. The required change would have to be 
general and would have to tend in the same direction for a 
considerable period of time. No short-range fluctuations and, 
above all, no merely local climatic changes would suffice. A 
displacement of the crust appears to meet all these require- 
ments. For a period of many thousands of years, some areas, 
moving toward the equator, would be growing warmer; 
others, moving toward the poles, would be growing colder. 
In the areas moving toward the equator (not necessarily 
reaching the equator, however, or even the tropics) the in- 
crease of sunlight would mean more luxuriant life condi- 
tions; for many species this might mean increased food 
supplies and an extended distribution. It would also be likely 



LIFE 323 

to mean increased competition with other forms. Many 
effects would depend upon whether the displacement carried 
the area in question into the wet tropics or into the dry horse 
latitudes, or merely from an arctic into a temperate climate. 
Meanwhile, of course, in areas displaced poleward, opposite 
trends would exist; here the forms of life would have to adapt 
to diminishing light, to increased cold, to decreased food 
supplies. 

What is important is that these changes of climate would 
apply over great areas of the earth. In one movement of the 
crust, two opposite quarters of the earth's surface would be 
moving equatorward while two others were moving pole- 
ward. Thus the climatic changes would be in the same direc- 
tion over very great areas: the entire distribution, perhaps, 
of many plants and animals. Mass transformation of life 
forms might therefore be expected to occur; not mass trans- 
formations of all life forms, of course, but merely one or two 
short steps in the mass transformation of one or a few kinds 
of plants or animals. New varieties might be established in 
great numbers, during a single movement of the crust; but 
by this I do not mean to imply that many new "species" 
would be. The latter may be the end results of a considerable 
number of displacements of the crust. I hope that the reader 
will not ask me to define "species." In this book I use the 
term simply to denote forms of life that are reasonably dis- 
tinct and relatively permanent. 

We must remember that the different areas of the earth's 
surface would be unequally shifted in a crust displacement. 
I have explained (Introduction) that the amount of the dis- 
placement would depend on whether an area was near to, or 
distant from, the meridian of displacement. Selection pres- 
sures would vary accordingly. 

Since we consider displacements to have taken place in 
short periods of the order of 10 or 20 thousand years, it seems 
likely that most plants and animals in areas radically dis- 
placed by a given movement would be unlikely to succeed 
in adapting. Some would migrate into areas having climates 



324 EARTH'S SHIFTING CRUST 

similar to their accustomed climates. Some would disappear. 
Some would develop varieties adapted to changed conditions. 
Even though there would be no wholesale creation of new 
plants and animals, the age-long process of change would 
have received an acceleration. 

Another important, generally accepted requirement for 
evolution, as already suggested, besides climatic change, is geo- 
graphical isolation to permit the development of new vari- 
eties. Geneticists agree that the larger the population of a 
given sort of plant or animal, the harder it is for a new variety 
to get established, because crossbreeding tends to destroy the 
new variety. If, however, populations are cut off from each 
other, and are reduced in numbers, a new variant has a much 
better chance to become dominant, and establish itself as a 
variety in that locality. As already pointed out, crust dis- 
placements can account for the alternation of conditions of 
geographical isolation and intercommunication at the tempo 
required to account for evolution, because they can account 
for rapid, recurrent changes of sea level. Let us now visualize 
the consequences of a displacement of the crust resulting in a 
subsidence of a continental area displaced equatorwards. Let 
us suppose a moderate subsidence of a few hundred feet only, 
over a period of a few thousand years. The result, of course, 
would be the deep intrusion of the sea into the continent. 
The sea would invade valleys, cutting off one part of the 
mainland from another, and creating islands and island 
groups. Many populations of the same kind of plant or ani- 
mal would thus be isolated, and left for many thousands of 
years to develop and establish new variant forms. 

Let us suppose many new varieties to have become estab- 
lished in the islands, and in areas of the mainland separated 
from each other by tongues of the sea. The next requirement 
of evolution is that these new varieties should be brought 
into competition and that the best adapted of them should 
be disseminated into more varied habitats. This might be 
brought about by a new movement of the crust, such as 
would displace this area poleward. The area will now be up- 



LIFE .325 

lifted, the sea will withdraw, and the life forms formerly 
isolated will mingle and enter a phase of competition. 

The situation that compels the adaptation of the forms of 
life to colder, drier climates (poleward displacement) also will 
adapt the forms of life to higher elevations, to mountain 
heights. Thus, if we consider all the effects of crust displace- 
ment, both toward the equator and toward the poles, we can 
see that crust displacement constitutes the most powerful 
engine imaginable for forcing life forms to adapt to all 
possible habitats. 



-/. The Distribution of Species 

Another important question is the problem of the origin of 
the present and past distribution of species over the face of 
the earth. Darwin and Wallace attempted to explain the 
numerous difficulties in this field, but their explanations 
have, in general, become less and less satisfactory with the 
passing years. These are the questions: 

a. How did certain species cross wide oceans to become 
established on different continents? 

b. What accounts for the richness of some islands, and the 
impoverishment of others, with respect to their fauna and 
flora? 

c. How did many kinds of animals and plants get dis- 
tributed from the north temperate to the south temperate 
zones, or from one polar zone to another, across the tropics? 

d. Why are certain species of fresh-water fish, inhabiting 
the lakes and rivers of Europe, also found in the lakes and 
rivers of North America? 

Some of the answers to these puzzling questions will al- 
ready be clear from what has been said about land bridges. 
Land bridges, or sunken continents, are obviously necessary 
to explain many of these distributions between continents 
and between continents and islands. Sunken continents have 
already been discussed (Chapter V). Here I would like to 



526 EARTH'S SHIFTING CRUST 

discuss the situation that confronts us if we are not allowed 
to postulate sunken continents or land bridges. 

If we cannot find an acceptable mechanism to account for 
the creation and destruction of land bridges (or sunken conti- 
nents) we are forced back upon the ingenious ' 'sweepstakes" 
idea, which has been much overworked, as an explanation 
of the distribution of species. This idea arose because it was 
observed that sea birds, or migratory birds, may carry the 
seeds of plants or the eggs of insects from continent to conti- 
nent, and that some species manage to cross, by chance, 
bodies of water on floating objects such as logs or even ice. 
By conveniently ignoring about nine tenths of the evidence, 
this idea has been given considerable importance. Even 
though many species have migrated in this way, the idea is no 
substitute for land bridges. Nor, it may be added, is one land 
bridge, at Behring Strait, able to do the work of explaining 
the infinite number of plant and animal migrations in all 
climatic zones in all geological periods. Many land bridges 
are required, and for these an explanation is necessary. The 
theory presented in this book, however, can explain the crea- 
tion and destruction of land bridges (and sunken continents), 
and therefore it can explain the distribution of species across 
large bodies of water. 

The impoverishment of certain island faunas and floras as 
compared with others may be understood as follows. Some 
of these islands may have rich faunas and floras because, in 
recent time, they have had land connections with adjacent 
continents. This would be true of the Philippines, of Java, 
of Sumatra, and of numerous other islands in that area, 
whose former continental connections with either Asia or 
Australia have been argued for by Wallace (446) and others. 
It is not a question of showing that the species in these 
islands came from the continents; it is simply true that there 
were land connections, and that the species wandered back 
and forth; we don't know where they originated. 

An island like Java can have a rich fauna and flora not only 
because of having had rather recent connections with the 



LIFE 327 

continent of Asia, but also because it is mountainous. This 
makes it possible, supposing at some time an equatorward 
displacement of the island into a warmer latitude, for tem- 
perate climate species to ascend into the mountains and so 
survive. Such variety of climatic conditions, due to differ- 
ences of altitude of different parts of the island, would favor 
the preservation of a rich flora and fauna. 

Let us contrast with Java the situation of a small island or 
island group, such as the Bermudas, the Azores, or the Ca- 
naries, where, in general, we find the life forms to be 
impoverished. These islands, often far from the nearest 
continent, may have been separated from them, of course, for 
long periods of time. Now let us suppose one of them, say 
the Azores, to be displaced through about 2,000 miles of 
latitude in one movement of the crust, in either direction. 
Where will the indigenous species go? Obviously, there will 
be no refuge for them; therefore, many of them will succumb. 
Subsequently, the sea will be an effective barrier to the re- 
population of the islands from the mainland. 

As to the distribution of life forms across the climatic 
zones, referred to as "bipolar mirrorism," Darwin proposed 
an explanation in Chapter 12 of the Origin of Species that 
can no longer be accepted. He supposed, % first, that glacial 
periods alternated in the Northern and Southern Hemi- 
spheres. This idea has long since been given up. Then, Dar- 
win reasoned that when there was an ice age in the Northern 
Hemisphere, the climatic zones would be displaced south- 
ward, and the temperate zone species would migrate south- 
ward. When that ice age ended, and the climate warmed up, 
the temperate species that had migrated southward would 
now ascend into the mountains, where they would survive, 
in the tropic zone. There are, of course, mountains in the 
tropics high enough to be snow-capped the year around; 
on these even arctic plants might exist. 

The next step, according to Darwin, would be the onset 
of an ice age in the Southern Hemisphere. Now the tempera- 
ture in the southern tropics would fall, and become temper- 



328 EARTH'S SHIFTING CRUST 

ate, and the temperate species wcmld descend from their 
mountains and migrate across the valleys southward to the 
south temperate zone. In this way the migration of the species 
from the northern to the southern temperate zone would 
be accomplished. 

Now this idea of the species clambering up and down the 
mountainsides in response to the changing weather is a good 
one, and gives us one key to the problem. Where Darwin 
went wrong was in his alternating ice age theory; he could 
hardly be blamed, in view of the prevailing ignorance about 
ice ages. Darwin, of course, lived at a time when people were 
first getting used to the idea of ice ages. But if Darwin was 
wrong, if ice ages do not regularly alternate in the Northern 
and Southern Hemispheres, how do we explain bipolar 
mirrorism? For some decades now, glaciologists have been 
holding grimly to the theory that ice ages were always simul- 
taneous in the two hemispheres. In maintaining this view, 
they have ignored the fact that they have made mincemeat 
of Darwin's explanation of bipolar mirrorism. But this does 
not concern them. They are concerned with explaining ice 
ages, not with the distribution of species. They have sug- 
gested no alternative explanation for the migration of species 
across the climatjc zones. Instead, they have constructed a 
theory that puts the migration of species, and even the sur- 
vival of tropical species, into the realm of sheer impossibility. 

They insist, we remember, that the temperature of the 
whole earth was simultaneously lowered in glacial periods. 
We have seen that at various times in the past great conti- 
nental icecaps have existed at sea level within the tropics, 
and even on the equator itself. I have already pointed out 
that if the world temperature had been lowered enough to 
permit a continental icecap in the Congo, there would have 
been no place of refuge for tropical species of plants and 
animals. Nowhere along the circle of the equator around the 
earth would any tropical species have survived. This would 
be equally true of land and sea forms of life. 

Bipolar mirrorism, however, presents no problems if we 



LIFE 329 

reconsider it in terms of displacements of the crust. One 
movement, let us suppose, takes the Rocky Mountains 2,000 
miles to the south. The species climb higher. Later, in a series 
of movements of the crust (not always, of course, in the same 
direction), the Rockies finally end up south of the equator, 
in a temperate climate. Now the species climb down, and 
occupy the temperate valleys of the Southern Hemisphere. 
The mountain chain has functioned as a ferryboat, simply 
transporting species back and forth. 

At this point it is interesting to reflect on how useful it is 
to have these high mountain ranges. A low mountain range 
would never do. It could never ferry a load of species across 
the tropical zone. 



5. The Periods of Revolutionary Change in Life Forms 

The reader may have gained the impression that, while cer- 
tain aspects of evolution have escaped satisfactory explana- 
tion, at least the process itself has continued evenly through 
all time. To this reader it may come as a shock, as it did to 
me, to learn that this is not at all the case. There have been 
remarkable variations in the rate of evolution. For long 
periods it has marked time, and then some force, hitherto 
unidentified, has initiated a phase of rapid change, a revolu- 
tion changing so many forms of plant and animal life as to 
alter the general complexion of life on the earth. All paleon- 
tologists appear to agree on this point. Dr. Simpson uses the 
term "Virenzperiod" to define the periods of rapid change. 
Others refer to "explosive" phases of evolution or to "quan- 
tum evolution." It must be understood that development 
during these periods is rapid only relatively; new forms are 
still not created overnight. 

One phenomenon that frequently occurs during these 
periods is termed "adaptive radiation." This is a kind of ex- 
plosion in which one form (or species) rapidly gives rise to 
dozens, scores, or even hundreds of new forms apparently at 



330 EARTH'S SHIFTING CRUST 

one and the same time. How is this phenomenon accounted 
for? 

We must distinguish between the biological process and 
the circumstances that cause it to occur. The process is easily 
explained. Let us suppose that a form of plant or animal is 
widely spread over a considerable area. Its total population 
may include some millions of individuals; over its whole 
distribution there will be local variations in the environ- 
ment, and consequently there will be selection pressures 
operating simultaneously but in different directions on differ- 
ent parts of the population in different habitats. New vari- 
eties of the plant or animal will tend to appear to take 
advantage of special opportunities offered by particular local 
environments. This sort of thing is always going on, but it 
does not, by itself, produce explosions of adaptive radiation, 

Something more is required. Normally, a new variety of 
any form has to compete with other forms already in posses- 
sion of the necessary supplies of food, light, and water. The 
situation that has the particular combination of these things 
required by a given plant or animal is referred to as its life, 
or ecological, niche. Naturally, if this niche is already effec- 
tively occupied the spread of the new variety is restricted, 
As an analogy, think of a garden in which you have set out 
one hundred expensive strawberry plants of a totally new 
variety, just before being called away for two months on 
urgent business requiring your presence in a foreign country 
What now happens? Weeds immediately take over the niche 
you had hoped to preserve (artificially) for the spread of the 
strawberry plants. Their spread is restricted, and their sur- 
vival may be threatened. 

In nature what seems to be required to permit the ver) 
rapid dissemination of many new variant forms of the orig 
inal plant or animal is an absence of competition. Empty life 
niches are required. The question is, How is an empty life 
niche produced? Occasionally, of course, it may have beer 
there from the beginning; it may never have been occupied 
because, presumably, there never was any form of life thai 



LIFE 331 

could utilize it, but after two billion or more years of evolu- 
tion, such primeval biological vacuums are few indeed. Life 
niches have, in general, been very well occupied for a very 
long time. Something is required, therefore, to empty them. 

This is where our theory comes in. The effects of a dis- 
placement can be visualized in two stages. In the first, a 
movement of a large continental area through many degrees 
of latitude might well cause a very general extermination 
of the inhabitants. We have seen how, in several instances, 
this occurred during the late Pleistocene (Chapter VIII). 
The consequence of the extermination of many kinds of 
plants and animals (which is not to say their extinction, for 
many of them might survive in other areas) would be to leave 
their life niches empty. 

The second stage, initiated by a new movement of the 
crust, would be marked by the opening up of avenues for the 
immigration of life forms from other land areas. Life forms 
entering the continent would now enjoy a field day. They 
would multiply; they would occupy rapidly a tremendous 
area and all manner of habitats; they would produce variant 
forms, and the variant forms would occupy appropriate 
niches. Thus explosive evolution would take place. The new 
forms need not always be immigrants; they could equally 
well be local survivors of the period of depopulation, of the 
displacement, who had somehow managed to hold their own 
under unfavorable conditions. It seems highly probable, 
indeed, that displacements of the earth's crust are the ex- 
planation of explosive evolution. 

We have already made mention of the fact that an interrela- 
tionship between the revolutionary periods in evolution and 
the critical phases of change in other geological areas has 
been noted by many observers. Lull, for example, says, 

. . . There are times of quickening, the expression points of evo- 
lution, which are almost invariably coincident with some great geolog- 
ical change, and the correspondence is so exact and so frequent that 
the laws of chance may not be invoked as an explanation (278:687). 



332 EARTH'S SHIFTING CRUST 

Umbgrove mentions two specific examples of this phe- 
nomenon: 

The most important point of all, as far as we are concerned, is 
that the two major periods of strong differentiation of plant life 
correspond with two major periods of mountain-building and glacia- 
tion of the Upper Paleozoic and Pleistocene (429:292). 

The same thing is described by Professor Erling Dorf, of 
Princeton (349:575-91). We need not take too seriously the 
small number of turning points mentioned by them for the 
reason that everything, after all, is relative. The turning 
points mentioned by Umbgrove might turn out to have been, 
in some respects, the most important turning points in the 
history of life, and yet there may have been a hundred lesser, 
but still very important, turning points. 

Geologists who have sought an explanation of the rela- 
tionship between biological and geological change have, in 
some cases, favored the idea that geological change, such as 
the formation of new mountain ranges, might have caused 
both ice ages and biological change. We have seen that this 
will not account for ice ages. We have also seen that geolo- 
gists now generally admit their failure to explain mountain 
building. It is unsatisfactory to attempt to explain the known 
by the unknown; it will not do to drag in mountain build- 
ing as the cause of evolution, when the former also is 
unexplained. 

Displacements of the earth's crust appear to be the con- 
necting link between these different processes: they explain, 
at one and the same time, ice ages, mountain formation, and 
the significant turning points of evolution. 



6. The Extinction of Species 

It has already been shown (Chapter VIII) that our theory can 
provide an explanation for the extinction of species. Some 
further discussion of this problem is, however, required. 
It has been suggested that the history of any particular 



LIFE 333 

species can be compared with the life of an individual, with 
its phases of youth, maturity, and old age. Thus, the ex- 
plosive period is the youth of a species, the period of quiet 
and prosperous enjoyment of its life niche is maturity, and 
its degenerative phase is its old age. Finally, extinction re- 
sults from the exhaustion of the vital force of the species. 
This theory assumes an innate cause, and a natural order for 
the succession of the phases. 

This idea has been widely disseminated, and in one form 
or another it has served to confuse all the issues and obscure 
the known facts. It is one more of those philosophical abstrac- 
tions that people resort to who come up against an unsolved 
problem and cannot stand the psychological tension of per- 
severing in the search for truth. It is important that the 
essentials of this matter should be made clear. 

In the first place, the idea that a species is analogous to an 
individual, and must go through similar phases, is a modern 
revival of the Scholastic logic of the Middle Ages, like the 
microcosm-macrocosm analogy (according to which some 
people have recently argued that since planets are satellites 
of the sun, and electrons are satellites of the nucleus of the 
atom, then planets are exactly like electrons, and must obey 
the same laws of physics). The alleged vital force, which is 
supposed to set a preordained limit to the life of a species, 
completely escapes scientific observation and experiment. 
It is not only a mere assumption, it is also an unjustified 
assumption. 

The facts of paleontology do not agree with the analogy of 
the life phases of a species with that of an individual. In very 
many cases the same phase may be repeated several times in 
the life of a species, and other phases may be omitted alto- 
gether, as we shall see below. For this reason the theory 
brings caustic comment from Dr. Simpson. After discussing 
the two phases of adaptive radiation (youth) and "intrazonal 
adaptation" (establishment in a stable but limited environ- 
ment), which is analogous to maturity which often do follow 
each other in this order he explains their relationship thus: 



334 EARTH'S SHIFTING CRUST 

The sequence radiation-intrazonal evolution is usual, simply be- 
cause radiation does not occur unless there are diverse zones within 
which evolution will follow. Occasionally, nevertheless, something 
happens to close the zones so soon that radiation is curtailed, or the 
intrazonal phase is even shorter than the radiation. The camariate 
crinoids, for instance, seem to have been in the full swing of a radia- 
tion when they all became extinct in the Carboniferous. . . . (390: 
232). 

We note that Dr. Simpson says, "something happens." What 
happens? He does not care to suggest what might happen to 
close the zones, to curtail the radiation, to destroy the species. 
No one has ever suggested a reasonable explanation of these 
things, but they can be understood as effects of repeated dis- 
placements of the crust. 

Dr. Simpson has remarked elsewhere that he does not ob- 
ject to the analogy of the species and the individual, provided 
it may be allowed that youth may follow maturity, and may 
occur more than once! 

Not only may phases occur in the wrong order, and be 
repeated, but also some may be omitted altogether. This 
seems particularly true of the last, or so-called senile, period. 
No concept has had so wide a currency with so little support 
in evidence as that of the alleged degeneration of species. 
The reasoning behind it is essentially specious: if a form of 
life becomes extinct, and if some "exaggerated" trait can be 
pointed to, which might have produced this extinction, then 
it is claimed that the species was degenerate. This is, of 
course, merely hindsight, because it ignores the fact that 
some of the oddest creatures in the world have lasted for 
millions of years and still exist. It is true that some kinds of 
plants and animals become adapted to very narrowly special- 
ized environments, so that an almost imperceptible change 
in the environment may destroy them. These forms may, if 
you like, be called overspecialized, but they cannot be called 
degenerate. No inner process of decay has taken place in the 
organism. Its extinction results from the external circum- 
stance that destroys its relationship with its environment. Is 
the specialist, who has spent his entire life in the study of 



LIFE 335 

the pre-Cambrian, and therefore is incapable of making his 
living in any field outside of geology, or even outside pre- 
Cambrian geology, degenerate? If he starves to death, is his 
extinction due to degeneration? The reasoning is analogous. 
But, supposing that we allow a phenomenon of degenera- 
tion in species, it is still true that most species disappear with- 
out showing any indication whatever of a decline of their 
'Vital force/' The majority of them are cut off in the vigor 
of maturity, or in "youth," as in the case of the camariate 
crinoids. Moreover, there is no rule as to the relative length 
of the different periods. Dr. Simpson remarks: 

Diversification may be brief or prolonged, and may be of limited 
scope or may ramify into the most extraordinarily varied zones cover- 
ing a breadth of total adaptation that would have been totally unpre- 
dictable and incredible if we were aware only of the beginning of 
the process (390:222-23). 

Again, he says, 

. . . Episodes of proliferation may come early, middle or late in 
the history of a group. This confirms the conclusion that adaptive 
radiation is episodic but not cyclic (390:235). 

We have already noted that Darwin recognized that the 
ordinary competition of species could not account for the 
mass extinction of whole groups, of which, even then, there 
were many known instances in the fossil record. Since his 
day, paleontologists have found very many more cases of 
apparently well-adapted species, which in some cases had 
flourished for tens of millions of years and yet suddenly dis- 
appeared, sometimes leaving their life niches empty, and at 
other times giving way to inferior species as their successors. 
For the Pleistocene alone, the last million years, as we have 
seen, the examples of this include the mammoth, the masto- 
don, the sabertooth cat, the giant beaver, the giant sloth, the 
giant bison, and countless extinct varieties of still existing 
forms like horses, deer, camels, peccaries, armadillos, wolves, 
bears, etc. Dr. Simpson, in discussing the extinction of the 
dinosaurs, remarks: 



336 EARTH'S SHIFTING CRUST 

It should be emphasized that these mass extinctions are not in- 
stantaneous, or even brief, events. They extend over periods of tens 
of millions of years. . . . This makes the phenomenon all the more 
mysterious, because we have to think of environmental changes that 
not only affected a great many different groups in different environ- 
ments, but also did so very slowly and very persistently. The only 
general and true statement that can now be made about, say, the ex- 
tinction of the dinosaurs is that they all lost adaptation in the course 
of some long environmental change the nature of which is entirely 
unknown (390:302). 

If the dinosaurs lost adaptation, it was not because they 
changed. The same is true of the sabertooth cat, which had a 
life span of 40,000,000 years and, according to Simpson, was 
apparently as well adapted at the end of that period as at 
the beginning (392:43-44). The gradual elimination of the 
dinosaurs can be understood as the result of constant shift- 
ings of the earth's crust, which eliminated these reptiles first 
in one area and then in another. No doubt, dinosaurs re- 
peatedly reoccupied areas from which they had previously 
been eliminated, but eventually perhaps much more re- 
cently than some people think they were destroyed. Being 
cold-blooded creatures, of course, they would find it quite 
intolerable to be shifted into the cold zones, but there is not 
the slightest reason to think they were degenerate. Simpson 
attacks the entire idea of degeneration of species (392:72, 81). 
He quotes Rensch: 

In innumerable cases lineages become extinct without there being 
recognizable in the last forms any sort of morphological or patholog- 
ical degenerative phenomena (390:292). 

Professor Dodson gives a good example of the piecemeal 
extinction of species. He cites the case of the mastodonts, 
relatives of the elephants, which became extinct first in the 
old world and then in the new (115:371). Other examples 
could be cited from the Pleistocene, when many species be- 
came extinct in the Americas, while their close relatives, such 
as horses, camels, and various kinds of elephants, survived 
in the Eastern Hemisphere. Now one might ask the question, 



LIFE 337 

If a species becomes extinct on one continent but continues 
to flourish on another, is it or is it not senile? What stage is 
it in then? We can understand all these events as the results 
of piecemeal destructions of animal populations in crust 
displacements. We can see in them the process of the creation 
of empty environments, preparing the way for a new stage 
of explosive evolution. Simpson directly suggests the connec- 
tion between these two things: 

. . . Opportunity may come as an inheritance from the dead, the 
extinct, who bequeath adaptive zones free from competitors. Jurassic 
Virenz for ammonites followed extinction of all but one family, per- 
haps all but one genus, of Triassic ammonites; early Tertiary mam- 
malian Virenz followed mysterious decimation of the Cretaceous 
reptiles. . . . (392:73)- 

There is another question regarding the extinction of 
species that should be answered. Perhaps it will be asked, If 
crust displacements killed off the dinosaurs, why did they 
not eliminate also the very numerous other reptiles that still 
survive? If the last displacement at the close of the Pleisto- 
cene eliminated the mammoth and certain other mammals 
from America, why did other animals survive? The answer 
is, essentially, that it is a question of the mathematical 
chances of survival. It is a question of the numbers of the 
animals, the geographical extent and variety of their habitats, 
their particular individual aptitudes, and the ever-present 
factor of sheer accident. It may be true that size militated 
against some species, but it may have worked in favor of 
others. The very largest animal of all the whale still sur- 
vives. Elephants compare favorably with all but the very 
largest extinct mammals. 



7. The Gaps in the Fossil Record 

One further point remains for our consideration. A feature 
of the fossil record that greatly impressed Darwin was the 
curious way in which species appear, full-blown, with no 



338 EARTH'S SHIFTING CRUST 

indication of transition forms, much like the mythical birth 
of Venus. The paleontologist suddenly comes upon a species, 
or a whole group of them, which have not been found be- 
fore. They are all fully evolved; they obviously have had 
long histories; there must have been hundreds or even thou- 
sands of ancestral forms for them; but absolutely no trace of 
the preceding forms can be found. It happened this way with 
the dinosaurs, which appeared in Africa, with a great many 
species already fully developed, at the beginning of the 
Mesozoic Era. They seem to have come, literally, out of noth- 
ing. Sometimes ancestral forms of a particular plant or ani- 
mal will be found at a great distanceon another continent, 
perhaps but always there appear to have existed many inter- 
mediary links, which have been lost. Even in the case of the 
horse, where an unusually good record exists, there are many 
missing links. 

A part of the reason for this situation is, of course, the 
imperfect preservation of the fossil record. There appear to 
be several reasons for this. Fossilization itself is a very rare 
event; very few individuals of any species are preserved, and 
the great majority of all the species that have existed have 
disappeared without a trace. Then, of the fossils that were 
preserved in the rocks since the beginning of the sedimentary 
record, about 95 per cent have been destroyed, since about 
that percentage of all the sedimentary rocks of the older 
periods has been eroded away and redeposited, with conse- 
quent destruction of all fossils. Finally, of the fossils that 
have been preserved, it is very unlikely that paleontologists 
can have seen and studied more than a very insignificant pro- 
portionlet us say, to put the matter as liberally as possible, 
that they may have seen one millionth of the existing fossils. 
Many of the latter, of course, are buried deep in the earth 
or under the numerous shallow seas, and will never be seen. 

But true as this is, it does not quite satisfy. Relatively few 
and scattered as fossils may be, it is still to be wondered at 
that we do not have a respectable handful of reasonably com- 
plete life histories. The light cast on this matter by the theory 



LIFE 339 

of crust displacement is quite startling. We have seen that 
such movements would necessitate frequent migrations of 
whole faunas and floras. It would necessarily follow, from the 
theory of crust displacement, that species would as a rule be 
separated by considerable geographical distances from the 
places of their origin. This would be all the more certain 
since the rate of development of new forms is probably very 
slow as compared with the rate at which crust displacements 
may occur. It could, actually, be rather seldom that one plant 
or animal would complete much of its life history in the same 
place. The "missing links" would usually have been sepa- 
rated by great geographical distances from the homes of their 
descendants. Moreover, the successive movements of the 
crust, with the resulting changes in the distribution of land 
and sea, would leave much of the fossil record under the pres- 
ent shallow (or even deep) seas, and out of our reach. 



8. Summary 

To sum up: it would seem that in crust displacements we 
have the missing factor that can bring all the other evolu- 
tionary factors into proper focus and correct perspective. By 
crust displacements we may accelerate the tempo of natural 
selection, provide the conditions of isolation and competition 
required for change in life forms, and account for periods of 
revolutionary change, for the distribution of species across 
oceans and climatic zones, and for the extinction of species. 
We may also account for the significant association of turn- 
ing points in evolution with geological and climatic changes, 
presenting them as different results of the same cause. But for 
crust displacements to have had these effects, and if they are, 
indeed, to account for the evolution of species, they must 
have occurred very often throughout the history of the earth. 



XI : CAMPBELL'S MECHANISM OF 
DISPLACEMENT 

i. The Logic of the Evidence 

Readers of this volume may have reached the conclusion 
that displacements of the earth's crust have occurred, perhaps 
frequently, and very recently in the earth's history, and yet 
they may doubt that the icecaps caused the displacements. 
It may seem to them that other causes may have brought 
about these effects, or perhaps that a combination of causes 
has done so. 

There are several reasons for concluding that the cen- 
trifugal effects of asymmetrically placed icecaps were, in fact, 
the cause of the displacements. The first of these is that con- 
tinental icecaps are the most massive and the most rapidly 
developed dislocations of mass known to have occurred at 
any time on the earth's surface. All other known geological 
processes subject to measurement, such as erosion and vol- 
canic activity, are inadequate in tempo or in quantity to 
produce equal centrifugal effects. No dislocation of mass 
within the earth, known or conjectured, can compare quanti- 
tatively in equal periods of time with the effect of an icecap 
of the magnitude of the present icecap in Antarctica. Every 
theory so far advanced to account for changes at the surface 
of the earth (such as displacements of the crust) by changes 
in depth have postulated long periods for the completion of 
the changes. The geological evidence presented in this book 
can be understood only in terms of displacements of the crust 
at very short intervals during at least a large part of the 
earth's history, with a most recent displacement through no 
less than 2,000 miles of latitude in a period of about 10,000 
years at the end of the North American ice age. 

All this evidence calls for a large displacing force that 



CAMPBELL'S MECHANISM 341 

will overcome the inertia of the crust and its friction with 
the layer below it, to continue the displacements to distances 
of the order of several thousand miles. It is essential to have 
a force that will not be absorbed and exhausted by the work 
of moving the crust. It is clear that the mechanism of cen- 
trifugal effect postulated by Campbell can meet this re- 
quirement because the effect increases in proportion as the 
uncompensated mass of the icecap is moved farther from the 
axis of rotation. At the same time, as I have already men- 
tioned, a cause of displacement is called for that will cease to 
exert these centrifugal effects at some distance from the pole, 
but long before the equator is reached. To accomplish this, 
the mechanism must provide that the mass responsible for 
the displacement must itself disappear en route, and, as we 
have seen, it must disappear rapidly. It seems that the melt- 
ing of the icecap, as the movement brings it into warmer 
latitudes, provides not only a sufficient but perhaps the only 
conceivable method of explaining the facts. 

Campbell has made this clear by computing the increase 
of the centrifugal effect with increasing distance from the axis 
for the present Antarctic icecap, assuming it to be uncom- 
pensated, and assuming its displacement, without melting, 
as far as the equator. He has shown (Table III, opposite p. 
341, and Figure XII, p. 343) that if the icecap should be dis- 
placed as far as the 45th parallel of South Latitude, the 
tangential component of its centrifugal effect would be mul- 
tiplied about six times. After this point, while the total 
centrifugal effect operating at right angles to the axis con- 
tinues to increase until the equator is reached, the tangential 
component declines, and yet it is clear that the movement, 
if the uncompensated mass itself remains intact, must con- 
tinue to the vicinity of the equator itself. The geological 
evidence already presented shows that this did not occur, but 
that the movements terminated at points about one third of 
the distance from the pole to the equator. 

In view of the apparently inescapable logic of the geo- 
logical evidence and of the centrifugal mechanics, we must 



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CAMPBELL'S MECHANISM 



343 



examine with some care the mechanism that Campbell pro- 
poses as an explanation of displacements. 



2. Calculating the Centrifugal Effect 

I have already mentioned how preliminary calculations were 
made of the possible centrifugal effect of the Antarctic cap. 
I have mentioned that the calculation was first made by 
Buker, and later somewhat revised by Campbell. However, 
Campbell recognized, early in his examination of the theory, 
that this effect, since it operated at right angles to the axis 
of rotation and was not tangential to the surface, would not 
produce a horizontal movement of the crust, even if the 
magnitude of the effect was sufficient for the purpose. It 
would be necessary, he felt, to find the tangential component 
of the total quantity of the centrifugal effect. He ac- 
complished this by the application of the principle of the 
parallelogram of forces (Figure XII). However, his use of the 




METRIC TOWS 



Fig. XII. The Centrifugal Effect of the Icecap. Use of the Parallelo- 
gram of Forces to Calculate the Tangential Component 



344 EARTH'S SHIFTING CRUST 

principle is not that usually presented in high school and 
college textbooks of physics. The definition of the law of the 
parallelogram of forces is as follows: 

If two forces acting on a point be represented in direction and 
intensity by the adjacent sides of a parallelogram, their resultant will 
be represented by that diagonal of the parallelogram which passes 
through the point (249:489). 

In the three parallelograms in Figure XII, the two forces 
acting on the point a are the force of gravity, represented by 
the line a-d (a radial line to the center of the earth), and the 
tangential component of the centrifugal effect of the icecap, 
represented by the line a-c, while the "resultant" of these 
forces is the diagonal a-b, at right angles to the axis of rota- 
tion. The reader will note that Campbell has here inverted 
the terms of the definition but without changing the quanti- 
ties of the forces in relationship to each other. The "re- 
sultant* ' in the definition is our starting point; it is the 
estimated total centrifugal effect of the icecap. But it is evi- 
dent that it is unimportant whether the given quantity is the 
diagonal or the side of the parallelogram; the parallelogram 
permits the finding of the unknown quantity from the known 
quantity, whichever the latter is. The parallelogram there- 
fore permits a finding of the quantity of the tangential com- 
ponent. The rotating effect of this force exerted on the 
earth's crust is illustrated by the weight shown in Figure XIV. 

By definition, the tangential component of the centrifugal 
effect is exerted horizontally on the earth's crust. Now the 
question arises as to whether this force will be exerted on 
the crust itself, or whether it will act on the earth's body as 
a whole, and thus tend to be dissipated in depth. This is the 
same as the question whether the icecap will tend to shift the 
whole planet on its axis or merely to shift the crust. We have 
already decided that it will tend to shift the crust only, be- 
cause of the existence of a soft, viscous, and plastic layer 
under the crust. We may therefore conceive of this force, 
the tangential component of the total effect, as acting on the 



CAMPBELL'S MECHANISM 345 

crust alone, while recognizing that the displacement of the 
crust involves frictional effects with the sublayer. We have 
seen that a special characteristic of the mechanism under 
discussion is that it provides a constantly growing force that 
will overcome this friction, rather than be absorbed by it. 



3. The Wedge Effect 

The problem to be solved by the calculation was to find the 
quantity of the centrifugal thrust of the icecap in terms of 
pressure per square inch on the earth's crust, so that this 
quantity could be compared with the estimated tensile 
strength of the crust. If these quantities should be found to 
be of about the same magnitude, it would follow that the 
icecap had the potentiality of bringing about the fracturing 
of the crust, which, because of the slightly oblate shape of the 
earth, was necessary to its displacement over the lower layers. 
Einstein, in a letter received during an early stage of the in- 
vestigation, suggested that this necessity for the fracturing 
of the crust was the only serious hindrance to crust displace- 
ments in response to centrifugal effects. He wrote: 

For your theory it is only essential that an excentrically situated 
mass rising above the mean level of the earth-surface is producing a 
centrifugal momentum acting on the rigid crust of the earth. The 
earth-crust would change its position through even a very small cen- 
trifugal force if the crust would be of spheric symmetry. The only 
force that I can see which can prevent such sliding motion of the 
crust is the ellipsoidic form of the crust (and of the fluid core). This 
form gives to the crust a certain amount of stability which allows the 
dislocation of the crust only if the centrifugal momentum has a cer- 
tain magnitude. The dislocation may then occur and be accompanied 
by a break of the crust. . . . (128). 

Campbell, visualizing the sliding of the crust, perceived that 
a bursting stress would be caused in the crust when parts of 
it were displaced toward or across the equatorial region, 
where the diameter of the earth is greater. It became possible 
to visualize it in the manner suggested by Campbell in the 



346 



EARTH'S SHIFTING CRUST 



lower left-hand drawing of Figure XIV. The drawing shows, 
in black, two wedge-shaped cross sections representing the 
earth's equatorial bulge, or that part of it underlying the 
areas of the crust moving equatorward in the displacement. 
Half of the bulge is, in fact, involved; the other half under- 
lies the areas of the crust being simultaneously displaced 
poleward, but these do not affect the point at issue. 

The reader will note that the equatorial bulge of the earth 
is represented in this drawing as lying underneath the crust, 
so that the crust is not a part of it. This is a new way of visu- 
alizing the bulge, introduced by Campbell, and justified by 
him on the ground that since the earth's crust is of the same 
general thickness all over the earth regardless of latitude 
(even though it may be of differing thicknesses from place to 




POLAR AX 1 5 



Fig. XIII. A Cross Section of the Earth Showing the Relation Between 
the Crust and the Equatorial Bulge 



CAMPBELL S MECHANISM 



347 




NORTH POLE 

CROSS SECTION OF EARTH ON 
96* EAST 



Fig. XIV. Various Aspects of the Wedge Effect 

The Antarctic continent is shown, with center of gravity displaced to 
the right, on a line representing the $6th degree of East Longitude. The 
figure at the right represents the continuation of the movement of the 
icecap along this meridian, mounting the bulge, which must be visualized 
three-dimensionally. The lower left-hand figure shows the vertical cross 
section of the earth under the icecap, with the two wedges pushing the 
crust out as it approaches the equator. The proportions of the wedges 
ate shown, and an equilibrium of equal and opposite pressures is indi- 
cated. The tangential pull of the icecap is indicated by the suspended 
weight. 



place, and under mountains, continents, and ocean basins), 
then the differences in the polar and equatorial diameters of 



EARTH'S SHIFTING CRUST 




CONVENTIONAL 

TYPE OF WEDGE: 



P PRESSURE OF ICECAP 7.5 I o'* SHORT TON8 

b - DEPTH OF WEDGE 6.0 MILK* 

Q pwesauRt AGAINST ' 

LITHOSPHCRE 



A.73IO 4MORT TONS 




CROSS SECTION OF EARTH AT 
96 



Fig. XV. The Wedge Effect 



the earth are accounted for by differences in the thicknesses 
of the layers underlying the crust, and the bulge itself repre- 
sents added matter in the subcrustal layers in the equatorial 
regions. 

The bulge, viewed in this way as lying beneath the crust 
appeared to form two wedges against which the crust had 
to be displaced by the centrifugal thrust of the icecap. Camp 
bell reached the conclusion that to estimate the bursting 
stress produced on the crust in the equatorial region, il 
would be necessary to apply the mechanical principle of the 



CAMPBELL'S MECHANISM 349 

wedge, which has the effect of multiplying the effect of an 
applied force. This principle is usually given as follows: 

The wedge is a pair of inclined planes united by their bases. In the 
application of pressure to the head or butt end of the wedge, to 
cause it to penetrate a resisting body, the applied force is to the 
resistance as the thickness of the wedge is to its length (249:512). 

This statement means that a wedge multiplies the splitting 
power (or bursting stress) produced by an applied force in 
the proportion of the length of the wedge to its thickness at 
the butt end. Figure XV shows the application of this prin- 
ciple to the earth. The formula for calculating the wedge 
effect is presented at the extreme left, where P = pressure (as 
thrust of the icecap transmitted to the crust), Q = the mutual 
pressure between crust and bulge, or bursting stress, h = the 
height (that is, the length) of the wedge, and b = the base or 
butt end. The bursting stress equals the pressure applied to 
the butt and multiplied by the ratio of the thickness of the 
butt end to the length of the wedge. The length of the wedge, 
in this case, is about 6,000 miles, and its thickness at the butt 
end is 6.67 miles, so that the ratio is about 1,000:1, and the 
quantity of the thrust of the icecap should consequently be 
multiplied by 1,000; however, there are two wedges, one on 
each side of the earth, and therefore the thrust is multiplied 
only 500 times. Nevertheless, the significance of such a multi- 
plication of the effect of the icecap is self-evident. 

It was not a simple matter to apply the principle of the 
wedge to the earth. As in the case of the principle of the 
parallelogram, the formula could not simply be copied from 
a textbook; it had to be imaginatively applied. For example, 
in the diagram P, or pressure, is shown exerted on the butt 
end, like a sledge hammer hitting the butt end of a wedge to 
split a log. But obviously, the thrust of the icecap is not, in 
the first instance, applied in this way. It takes an act of the 
imagination to realize that in effect it amounts to the same 
thing. The icecap is really pushing or pulling the crust 
toward the equator on both sides of the earth, but the matter 



350 EARTH'S SHIFTING CRUST 

may just as well be looked at in the opposite way, as if the 
icecap and crust stood still, or were under no horizontal 
pressure, but force was being applied to the butt end of the 
wedge. Either way, the mathematics is the same. Campbell's 
application of this principle to the problem of estimating the 
bursting stress on the crust was discussed with physicists, in- 
cluding Frankland, Bridgman, and Einstein (see below), none 
of whom questioned its soundness. 

After finding the quantity of the total stress on the earth's 
crust produced by the centrifugal effect transmitted from 
the icecap, Campbell reduced it to pressure per square inch 
by dividing it into the number of square inches in a cross 
section of the earth's crust, assuming an average thickness of 
the crust of about 40 miles. This estimate of the crust's thick- 
ness is a liberal one, since some writers, including Umbgrove, 
suggest that it may be no more than half as much. Since a 
lesser thickness for the crust would mean a higher figure for 
the bursting stress per square inch, an error in this direction 
here may serve to counter the effect of the possible partial 
isostatic compensation of the icecap, which we have disre- 
garded in the tentative calculation of its centrifugal effect. 
Thus, if half the icecap is isostatically compensated, but the 
crust is only 20 miles thick, then Campbell's estimate of the 
pressure per square inch will be unchanged. 

Campbell found that the bursting stress on the crust per 
square inch amounted to about 1,700 pounds (see p. 361). In 
comparison with this, I found that the crushing point of 
basalt at the earth's surface has been estimated, from labora- 
tory experiments, at 2,500 pounds. A number of points must 
be considered in reaching conclusions regarding the possible 
significance of these comparative figures. First, the crushing 
strength of any rock is considered to be higher than its 
tensile, or breaking strength. Thus, the tensile strength of 
basalt, the principal constituent of the earth's crust, is proba- 
bly considerably closer to the estimated quantity of the 
bursting stress. A second important consideration is that 
the earth's crust is unequal in thickness and strength from 



CAMPBELLS MECHANISM 351 

place to place, and is everywhere penetrated by deep frac- 
tures. It would naturally fail at its weakest point. As we shall 
see below, Einstein, in view of these facts, said that he would 
be satisfied as to the plausibility of the mechanics of this 
theory if the ratio of the bursting stress to the strength of the 
crust was 1:100. The ratio as shown by Campbell is very 
much closer than the ratio demanded by Einstein. It seems 
therefore reasonable to suppose that at some point of the 
future growth of the icecap, which is now, it appears, still 
growing, the crust may respond to the increasing bursting 
stress by fracturing. When this occurs, it may be expected 
that a process will begin of gradual fracturing and folding of 
the crust, accompanied by the beginning of its displacement 
over the underlying layers. 

Campbell has pointed out that no very great force is re- 
quired to accomplish a widespread fracturing of the crust 
during a displacement. At the first local failure of the crust 
in response to the bursting stress, the stress will be relieved 
at that point, to become effective immediately at an adjacent 
point. Thus the fracture will travel through the crust with- 
out the application of additional force. From this it is clear 
that the steady application of a small force would suffice to 
fracture the crust to a great distance. In his conversation with 
Einstein, an account of which is given below, Campbell gave 
a convincing illustration of this principle. 

The ability of the crust to resist fracture is slight. Jeffreys 
found that a strain equal to the weight of a layer of rock 2,200 
feet in height would fracture it to its full depth (238:202). 
It is clear that the tensile strength of the crust does not com- 
pare with its crushing strength, which, also according to 
Jeffreys, is sufficient to enable it to transmit mountain-mak- 
ing stresses to any distance. Campbell visualizes the proc- 
ess of crust displacement not as a continuous movement but 
as a staged movement resulting from an interaction alter- 
nately of the direct thrust of the icecap and of the bursting 
stress. He writes: 



352 EARTH'S SHIFTING CRUST 

. . . There are two distinctly separate functions performed by the 
mass of the icecap. . . . The first is the centrifugal momentum caus- 
ing the lithosphere to change its position in relation to the poles. . . . 
When the lithosphere comes to a standstill for want of a sufficient 
force, the second function of the icecap gets busy and builds up a 
pressure of tremendous potential, five hundred times the force pro- 
duced by the icecap, and will continue to add to this pressure at the 
rate of five hundred times the increasing pressure of the growing 
icecap, until it finally splits the lithosphere. Then the pressure will 
drop, and the first function will take hold, and once again start to 
move the lithosphere. This alternate action will continue to take 
place until the icecap is destroyed. . . . 

. . . The wedge does, not multiply the power of the centrifugal 
momentum, as such. The power disposed for the movement of the 
lithosphere remains the same as it always has been, but the static 
pressure that will fracture the lithosphere, thereby permitting the 
centrifugal momentum of the icecap to start moving the lithosphere, 
will be multiplied by 500. 

The wedge has been functioning ever since the first permanent 
snow fell on the Antarctic continent; it is functioning today. ... At 
the same time, die centrifugal momentum of the icecap is just stand- 
ing by, waiting for the lithosphere to fracture and be released for the 
journey toward the equator. The tensile strain will fade away with 
the faulting of the lithosphere, but should the fractures freeze up 
again from any cause, the tensile strain will tend to build up again, 
and the same series of actions will repeat themselves (66). 

We saw that the process that destroyed the Wisconsin ice* 
cap was several times interrupted and renewed in alternating 
withdrawals and readvances of the ice, which we have ex- 
plained as resulting from episodes of massive volcanism. 
These phases appear to correspond to the alternating phases 
of the process of displacement as suggested by Campbell, 
which would naturally have been accompanied by volcanic 
activity. 



4. Some Difficulties 

A number of objections have been raised, in the course of 
consultations with specialists, to the mechanism of displace- 



CAMPBELL'S MECHANISM 353 

ment suggested by Campbell. We have considered these ob- 
jections, and they do not appear formidable. I am summariz- 
ing some of these in the following pages, in order that the 
reader may know, if any of these have occurred to him, that 
they have already been given consideration. 

a. The question of friction with the subcrustal layer. It 
may at first appear that friction would be a powerful brake 
on any extensive displacement of the crust, and unquestion- 
ably it would have an effect. Yet there are several mechanical 
factors that could aid a displacement. A leading considera- 
tion is that the suggested movement is a gliding motion. 
Gliding is the most economical form of motion. It has been 
said, in fact, that gliding constitutes an ideal form of motion 
that utilizes 100 per cent of energy, as opposed to the sphere 
and the cylinder, which, being round, lose 30 per cent of 
their energy in rotation, which reduces their speed consider- 
ably. Frankland has suggested that a rise of temperature at 
the interface of the crust and the lower layer, as the result 
of friction, could facilitate a displacement. Campbell con- 
siders that the underlayer, or asthenosphere, would act more 
like a lubricant than a retardant. He compares the movement 
to the motion of ice floes: ". . . Observe how vast fields of 
ice are started in motion just by the friction of the wind on 
the surface of the ice. . . . Again, you will see the same 
thing by visiting a pond where they are cutting ice. You will 
see men pushing around blocks of ice of three or four hun- 
dred square feet with the greatest ease as long as the ice is 
floating in the water. . . ." 

b. The question of the extent of the displacement. It has 
been questioned whether a displacement of the crust might 
not terminate at an early stage because of the melting of 
the icecap as it moves into lower latitudes. Campbell, how- 
ever, has pointed out that as the icecap moves equatorward 
from a polar region, the ice will continue to accumulate on 
the rear or poleward side, and that this will have the effect 
of prolonging the motion of the crust. In some circumstances, 
if the icecap happened to be situated on a very large land 



354 EARTH'S SHIFTING CRUST 

mass, this might mean a long continuation of the movement. 
An icecap in Eurasia might move the crust a great distance. 
It is obvious that a natural point for the termination of the 
movement will be the arrival of an oceanic area at the pole, 
so that the rearward build-up of the ice is brought to an end. 
This would appear to have happened in the last movement, 
when the southward shift of North America seems to have 
brought the Arctic Ocean into the polar zone. 

c. The question of the possible suspension of movements 
if both poles should happen to be situated in oceans. This is 
one of the more important objections that have been raised 
to Campbell's mechanism of displacement. Yet, it appears 
that it is much less formidable a difficulty than it seemed at 
first glance. It might be supposed that the eventuality of 
having both poles in water areas would be certain to occur; 
that is, it would have occurred early in the earth's history, 
and would have stopped crust displacements by putting an 
end to the formation of great polar icecaps. However, a 
further examination of this objection reveals weaknesses in it. 

In the first place, the very peculiar placing of the conti- 
nents with respect to the ocean basins renders such an event 
almost impossible. All the six continents are placed dia- 
metrically opposite oceans on the other side of the globe. 
Ninety-five per cent of all the land on the globe lies opposite 
water. Moreover, the oceans are surrounded by continental 
shelves that extend for considerable distances, and there are 
island areas in the oceans where the water is comparatively 
shallow. We have seen that, according to Gutenberg, any 
part of the earth's surface moved poleward by a crust dis- 
placement would stand higher relatively to sea level. Any 
area now near the equator would be raised considerably if 
moved to a pole, by reason of the variation of gravity alone, 
while other factors might add to the vertical movement 
(Chapters IV, V, VI). Displacements could result in raising 
the continental shelves, shallow seas, and island areas above 
sea level. The two or three displacements of the crust in the 
same direction that would be required to move any area from 



CAMPBELL'S MECHANISM 355 

near the equator to the vicinity of a pole might produce 
major increases in elevation. Finally, it would be necessary for 
both poles to be so far away from the nearest land as to pre- 
vent the growth of icecaps on any side, for an icecap formed 
all on one side of a pole and at a considerable distance from 
it would have a very great centrifugal effect proportionately 
to its size. Campbell carried out a series of careful measure- 
ments of the globe to find out how many possibilities actually 
exist at the present time for the location of both poles in 
water. He found that there is only one such position, where 
one pole would be in the South Atlantic and the other in the 
North Pacific between the Marshalls and the Carolines. But 
the latter area, in the course of its displacement from its pres- 
ent latitude to the vicinity of a pole, could easily be raised 
above sea level. 

It cannot be denied, despite this, that there exists a real 
possibility that at various times during the history of the 
globe both poles have been, in fact, situated in oceanic areas. 
Unquestionably, this would have resulted in the temporary 
cessation of the formation of great polar icecaps, and there- 
fore of displacements of the crust. However, there is no rea- 
son to conclude that this would have meant a permanent 
cessation of crust displacements. We must not forget that 
Gold has suggested a mechanism by which a shift of 90 de- 
grees in the positions of the poles could occur in periods of a 
million years. In this way a period without crust displace- 
ment could be ended by the gradual movement of a new land 
area to a pole. It is even quite possible that the accumulation 
of inequalities of mass within the crust itself, as the result of 
erosion or of igneous processes, might eventually produce a 
displacement without the agency of an icecap. 

d. The question as to why the postulated centrifugal effect 
has not prevented the accumulation of the icecap. One com- 
mentator has pointed to the well-known fact that ice flows 
outward in all directions from a central point or points, 
through the effects of its own weight, and has argued that the 
centrifugal effect should operate to make the icecap flow off 



356 EARTH'S SHIFTING CRUST 

into the sea rather than to bring about a transfer of centrif- 
ugal momentum from the icecap to the crust. This objection 
has a certain plausibility at first glance, and yet it is invalid 
for the following reason. We know that according to classical 
mechanics any mass deposited upon the earth's surface (pro- 
vided that surface is already in gravitational equilibrium) will 
be acted upon by the earth's rotation, and will give rise to a 
centrifugal effect. So much cannot be denied. It is also true 
that the resulting centrifugal momentum will act upon the 
ice and can be expected to accelerate to some degree the 
rate of flow of the ice in the direction of the thrust (not in 
all directions). In the case of the present Antarctic icecap 
this might mean a slightly increased rate of flow across the 
broadest section of the continent, in the direction of the 
meridian of 96 E. Long, (see the map of Antarctica, Intro- 
duction, p. 18). However, the crux of the matter is, obviously, 
the ratio of the rate of flow to the rate of accumulation of the 
ice. It is clear, on the one hand, that new ice, until brought 
within the equilibrium surface of the globe by isostatic ad- 
justment, must give rise to centrifugal effects; and on the 
other hand it is quite clear that, despite this, the icecap has 
continued to accumulate. Why does it happen that the cen- 
trifugal effect does not produce a flow-off of ice from the 
continent at a rate equal to the rate of accumulation? The 
answer to this is, obviously, that ice presents considerable 
resistance to flow. It flows only under considerable pressure, 
and is otherwise a solid. Moreover, in Antarctica, and pre- 
sumably in any polar icecap, the prevailing low temperatures 
cause the ice to have increased rigidity. It is also thought that 
the ice below the superficial layers of a great ice sheet is stag- 
nant, and that only the upper layers move. This means that 
the ice that is in contact with the ground is fixed to the 
earth's surface. The viscosity, or stiffness, of the ice in turn 
means that a drag is imparted by the upper layers to the 
lower layers, and by them to the underlying crust. Thus the 
centrifugal momentum is transmitted to the crust. Finally, 
the supposition of the gliding off of the icecap is rendered 



CAMPBELL'S MECHANISM 357 

more improbable by the uneven topography of the continent 
and especially by the great fringing mountain ranges. We 
have cited Einstein's opinion that the flow-off of ice from 
Antarctica in the form of icebergs is an insignificant percent- 
age of the annual ice accumulation. 

e. The question as to whether the centrifugal effect postu- 
lated in this theory exists at all. Some commentators have 
rejected the idea that a large total centrifugal effect may be 
created by the asymmetric accumulation of an icecap. They 
have agreed only to the existence of a centrifugal effect that 
may be created if the center of mass of an object is elevated 
above the equilibrium surface of the earth. This has been 
termed the Eotvos effect. It does not depend upon the exist- 
ence of excess mass at a point. It may be illustrated by an 
iceberg floating in water. The ice is in gravitational balance, 
having displaced its weight of water. But one tenth of its 
weight is above the surface of the water. The center of its 
mass is therefore higher than the center of the displaced 
water. If the center of its mass is further from the earth's 
center, it is now moving around the earth's center at a faster 
rate. It has been accelerated, and the tangential component 
of the acceleration will tend to move it toward the equator. 

This concept is well known in geophysics, and conse- 
quently it has been the customary mode of considering any 
question involving centrifugal effects on the earth's surface. 
But the effects that may arise from an accumulation of ice 
that has not been brought within the equilibrium surface of 
the earth by isostatic adjustment, and which therefore con- 
stitutes an accumulation of excess mass at a point on the 
surface, have not received equal attention. I have already 
mentioned the fact that the idea came to both Bridgman and 
Daly as a new idea, and one that seemed to them worth in- 
vestigating. Because of the special importance of this issue, 
I am presenting a more detailed discussion of it below. 

f. The question as to whether the crust is strong enough 
to transmit the centrifugal momentum of the icecap. A num- 



358 EARTH'S SHIFTING CRUST 

ber of consultants have been in doubt on this point because 
of their knowledge that the crust is, from certain points of 
view, very weak. It has little tensile strength, and as a conse- 
quence cannot bear heavy loads without fracturing or giving 
way by plastic flow. However, tensile strength and crushing 
strength are two very different things. A bar made of a brittle 
but hard substance will have little tensile strength, but con- 
siderable force may be required to crush it. The rocks com- 
posing the earth's crust are highly rigid, and therefore, de- 
spite the fact that they have little tensile strength, such as 
would be required to contain vertical stresses, they have 
enormous strength to resist horizontally applied compressive 
stresses. They simply cannot be compressed to any extent, 
and only an enormous force will produce plastic flow. The 
rocks of the crust are so rigid (despite the fact that they do, 
of course, possess a certain small degree of elasticity) that the 
penetration of the crust by fractures does not seriously mod- 
ify its power to transmit horizontal or tangential stresses. 
There is geological evidence in the mountain systems, in the 
planetary fracture systems, in the great globe-encircling can- 
yon system recently discovered by Ewing, that stresses have 
been applied to the earth's crust as a whole, and various geol- 
ogists, including Hobbs and Umbgrove, have made state- 
ments to that effect. 

A proper understanding of this question requires that the 
magnitude of the stress and its mode of application should 
be considered. An enormous pressure per square inch, espe- 
cially if applied all at once, might cause local deformation of 
the crust by bringing about rock flow, as it has been sug- 
gested by Bridgman (p. 189), but the stresses that we suppose 
to derive from the icecap are not of this order, nor do they 
reach their maximum intensity until after a period of gradual 
growth during which they could be transmitted to the crust 
as a whole. The icecap produces a gentle pressure, slowly 
growing and steadily applied over a considerable length of 
time, incapable of radically deforming the crust adjacent to 



CAMPBELL'S MECHANISM 359 

itself, but capable of exerting a persistent push on the earth's 
crust. 

If it were possible to exhaust the centrifugal effect of the 
icecap by the absorption of energy in a local deformation of 
the crust, the matter might wear a different aspect. But we 
are to remember that, if the yielding of the crust or its dis- 
placement as a whole allows the displacement of the ice mass 
farther from the axis of rotation, the centrifugal effect is 
thereby multiplied. In these circumstances the centrifugal 
momentum cannot be absorbed locally, but must be trans- 
mitted to the entire crustal shell of the earth. 

Jeffreys has remarked that the earth's crust can transmit 
mountain-building stresses to any distance (238: 2 



5. The Calculations 

The following are the calculations of the centrifugal effect 
of the present Antarctic icecap, and of the resulting bursting 
stress on the crust, as worked out by Campbell. The phraseol- 
ogy is in part that of Dr. John M. Frankland, of the Federal 
Bureau of Standards, who was kind enough to review these 
calculations. 

a. Calculation of the Centrifugal Effect of the Rotation of 
the Antarctic Icecap: 

Assume isostatic adjustment o, center of gravity of the ice- 
cap 345 miles from the polar axis, and volume of the ice 
equal to 6,000,000 cubic miles. 

W = Weight of the icecap = 2.500 X 1Ql6 short tons. 

F = Centrifugal effect in pounds = , where 

gR 

v Velocity of revolving icecap, 132 feet per second, 
R = Distance from the axis of rotation to the center of 
gravity of the icecap = 345 miles = 1,821,600 feet, 
g = Acceleration due to gravity = 32. 



360 EARTH'S SHIFTING CRUST 

F _ Wv 2 _ 2.5 X i 16 X 



gR 32 X 1,821,600 

43*870.75 X iQ 16 _ 

58,291,200 

7.5 X l 12 short tons = 6.8 X l 12 metric tons, 
total centrifugal effect, 6.8 X l 12 metric tons, 
radial force tangential to the earth's surface, 
6.8 X 1C)2 metric tons (see p. 343). 

This, of course, is an upper estimate, which may be too large 
by a factor of two or three. 

b. Calculation of the Bursting Stresses on the Lithosphere: 

An approximation of the bursting stress caused by this cen- 
trifugal effect can be reached by simple methods as follows. 
More elaborate approaches hardly seem justified in view of the 
uncertainty of the magnitude of the centrifugal force. 

It is assumed that the entire resistance to the motion of 
the lithosphere arises from the fact that the earth is not a 
perfect sphere, but is an oblate spheroid. The tangential, or 
shearing, stresses between the lithosphere and the underlying 
asthenosphere are considered negligible because of the time 
factor, and because of the assumed viscosity of the astheno- 
sphere. If one considers the great circle passing through the 
center of gravity of the icecap, at right angles to the meridian 
of centrifugal thrust of the icecap, it is evident that the cir- 
cumference of this great circle will be increased if the icecap 
is displaced away from the pole. Of course, any stress system 
that arises in this way will be two-dimensional, but one will 
hardly be in error by a factor of more than two, if one neg- 
lects the two-dimensional character of the stresses and as- 
sumes instead that they are uniaxial. The only purpose of 
this computation is, of course, to show the order of mag- 
nitude of the effect. 

With this kind of approximation, one may view the equa- 
torial bulge as a kind of wedge up which the lithosphere is 



CAMPBELL'S MECHANISM 361 

being pushed. There are, of course, two wedges, one on each 
side of the globe. 

The bursting stress is the product of the tangential effect 
of the icecap by the ratio of the gradient of the bulge: 

(1) Thickness of bulge (wedge) at its butt end nn 6.67 miles. 

(2) Ratio of travel to lift, of bulge wedge = 6, 152: 6.67 

(3) Stress, on cross section of the lithosphere (taken as 
40 miles thick) = 7.5 X 1Ql2 X 6,152 

6.67 X 2 
= 34588 X 1Ql5 short tons. 

_ 34588 X io 15 7 

~ 5 = 3-5 X io 7 

99> 8 94 

short tons per sq. mi. 
Approximately 1,700 Ibs. per sq. in. 



6. Notes of a Conference with Einstein 

In January, 1955, Mr. Campbell and I had the privilege of 
a conference with Einstein at which a number of important 
questions relating to the theory were discussed. Subsequently, 
I prepared the following statement, which I submitted to 
him for his approval. He approved it as an accurate report of 
our discussion, but he desired that it should not be inter- 
preted as an official endorsement on his part of Mr. Camp- 
bell's calculations in detail, which he had had insufficient 
opportunity to study. Those present at the meeting included 
Dr. Einstein, Mr. Campbell, Mrs. Mary G. Grand, and myself. 

After the introductory remarks, Mr. Hapgood explained 
to Dr. Einstein that while, in the development of the theory, 
he had himself been concerned mainly with the field evi- 
dence in geology and paleontology, Mr. Campbell had con- 
tributed the basic concepts in mechanics and geophysics. 

Mr. Hapgood explained further that Mr. Campbell's cal- 
culations had now advanced to a point where he felt that a 
consultation was necessary. The principal question was 



362 EARTH'S SHIFTING CRUST 

whether the tangential portion of the centrifugal effect re- 
sulting from the rotation of the icecap was of the correct 
order of magnitude to cause fracturing of the earth's rigid 
crust. Dr. Einstein had stated in a letter to Mr. Hapgood 
that, owing to the oblate shape of the earth, the crust could 
not be displaced without fracturing and that the tensile 
strength of the crust, opposing such fracturing, was the only 
force he could see that could prevent a displacement of the 
crust. He had already suggested, therefore, that it would be 
necessary to compare the bursting stresses proceeding from 
the icecap with the available data on the strengths of the 
crustal rocks. 

It was this problem that now, through the calculations 
made by Mr. Campbell, seemed to be solved. 

Mr. Campbell explained to Dr. Einstein the principles he 
had followed in making the calculations. He used photostatic 
drawings as illustrations. He showed that the crust, in at- 
tempting to pass over the equatorial bulge of the earth, 
would be stretched to a slight degree. A bursting stress would 
arise that would tend to tear the crust apart. This stress 
would in all probability exceed the elastic limit of the crustal 
rocks: that is, they would tend to yield by fracture, if the 
stress was great enough. Dr. Einstein said, Yes, but he won- 
dered how an equilibrium of force would be created? Mr. 
Campbell pointed out that two equal and opposite pressures 
would arise, since, at the same time, on two opposite sides 
of the globe, two opposite sectors or quadrants of the crust 
would be attempting to cross the bulge. 

Dr. Einstein agreed that this was reasonable, but raised the 
question of the behavior of the semiliquid underlayer of the 
bulge, under pressure from the rigid crust. After some dis- 
cussion it was agreed that this underlayer, despite its lack of 
strength, would not be displaced, because of the effect of the 
centrifugal momentum of the earth. 

Mr. Campbell then explained the application of a prin- 
ciple by which the tangential stress proceeding from the ice- 
cap was greatly magnified. He considered that the bulge of 



CAMPBELL'S MECHANISM 363 



the earth, starting with zero thickness at the poles, and 
proaching 6.67 miles in thickness at the equator, behaved 
physically as a wedge resisting the movement of the crust. 
Since the distance from pole to equator is about 6,000 miles, 
the ratio of this wedge was 1,000:1; but the existence of two 
wedges on opposite sides of the globe reduced the ratio to 
500:1. The icecap's tangential effect, multiplied by 500, and 
divided by the number of square inches of the cross section 
of the lithospheric shell at the equator (assuming the crust 
to be 40 miles thick), produced a bursting stress on that shell 
of 1,738 pounds per square inch. After examining each step 
in the argument twice Dr. Einstein had the impression that 
the principles were right, and that the effects were of the 
right order of magnitude. He stated that he would be satis- 
fied if the bursting stress and the strength of the crust were 
in the ratio of not more than 1:100, since the crust varied 
so greatly in strength from place to place, and would un- 
doubtedly yield at its weakest point. 

Mr. Campbell explained an effect he had often observed, 
which illustrated the process by which the crust might yield 
to fracture. A common method of splitting a block of granite 
is to drill two small holes, about six inches apart, near the 
center of the long axis of the granite, and insert and drive 
home a wedge in each hole, A bursting stress of sufficient 
magnitude is brought to bear to split the rock. However, the 
rock is not split all at once. Enough stress is brought to bear 
to start a fracture, but the fracture does not take place in- 
stantaneously. If the wedges are put in place in the evening, 
it will be found next morning that the whole rock has been 
split evenly along a line extending through the two holes. 
The fracture has slowly migrated through the rock during 
the night. The force required to split rock in this way is but 
a fraction of that required to split it all at once. So far as the 
earth's crust is concerned, what is required is not a force suf- 
ficient to split it all at once, but simply a force sufficient to 
initiate a fracture or fractures, which will then gradually 



364 EARTH'S SHIFTING CRUST 

extend themselves during possibly considerable periods of 
time. 

Mr. Hapgood next described the geological evidence of 
world-wide fracture systems extending through the crust, and 
weakening it, and the remarkable similarity of these patterns 
to those which, theoretically, would result from a movement 
of the crust. Dr. Einstein expressed the keenest interest in 
this evidence. 

Mr. Hapgood referred to the Hough-Urry findings of the 
dates of climatic change in Antarctica during the Pleistocene. 
Dr. Einstein stated that the method of radioactive dating de- 
veloped by W. D. Urry was sound and reliable. As a re- 
sult, Dr. Einstein was in full agreement that the data from 
Antarctica, indicating that that continent enjoyed a tem- 
perate climate at a time when a continental icecap lay over 
much of North America, virtually compel the conclusion that 
a shift of the earth's entire crust must have taken place. 

Dr. Einstein asked Mr. Hapgood what objections geologists 
had been making to the theory. Mr. Hapgood replied that 
it was principally a question of the number of such move- 
ments, Urry's evidence would imply four such displacements 
at irregular intervals during the last 50,000 years. 1 Dr. Ein- 
stein replied that this seemed to be a large number. How- 
ever, he said, if the evidence could not be explained in any 
other way, even this large number would have to be accepted. 
The gradualistic notions common in geology were, in his 
opinion, merely a habit of mind, and were not necessarily 
justified by the empirical data. 

At this point the discussion turned to astronomy. Mr. Hap- 
good did not understand why men who would boggle at the 
rate of change required by the theory of crustal movements 
thought nothing of accepting the view that the entire uni- 
verse had been created in half an hour. Dr. Einstein said that, 
unfortunately, the evidence seemed to point that way. After 

iThis figure was subsequently revised, in the light of much geological evi- 
dence (Chs. VII, VIII, IX), to three displacements in the last 130,000 years. 



CAMPBELL'S MECHANISM 365 

considerable discussion he added that it was not, however, 
necessary to take the present state of our knowledge very 
seriously. Future developments might show us how to reach 
a different conclusion from the evidence. Much that we re- 
gard as knowledge today may someday be regarded as error. 
Toward the end of the interview Dr. Einstein indicated a 
number of points where further research would be desirable. 
He suggested the need for a gravitational study of the Antarc- 
tic continent, and for a study of the rates of crustal adjust- 
ment to increasing or decreasing loads of ice. He commented 
upon the difficulties that confront those who wish to intro- 
duce new theories, and quoted Planck's remark that theories 
change not because anybody gets converted but because those 
who hold the old theories eventually die off. 



7. Isostasy and Centrifugal Effect 

As I have mentioned, there is a possibility of two points of 
view regarding the particular centrifugal effect postulated 
by Campbell and myself. It is therefore necessary to provide 
additional clarification of some of the points at issue. To a 
certain extent it may be a question of a situation in which 
new definitions or clearer definitions of accustomed terms 
are called for, but it also appears to us that in some cases, at 
least, physicists whom we have consulted in the course of our 
work are proceeding upon the basis of assumptions that are 
in conflict with ours. Therefore, it is necessary to re-examine 
these assumptions. A comprehensive discussion of the matter 
must begin with a review of the broader questions of the 
mechanics of rotation already briefly referred to in the In- 
troduction. 

The existence of a very common misunderstanding re- 
garding the mechanics of the earth's rotation, particularly 
related to the problem of the stability of the poles, was made 
clear to me by a difference of opinion that arose at the be- 
ginning of my inquiry. Brown, whose work was the starting 



366 EARTH'S SHIFTING CRUST 

point of my own, was an engineer, and his concepts of the 
earth's motions were based upon simple mechanics. He un- 
derstood gyroscopic action, and the stabilizing role of the rim 
of a rotating flywheel. He also understood the laws of cen- 
trifugal effect as applied to weights eccentric to the axes of 
spin of rotating bodies. It was my good fortune that Camp- 
bell, who was to carry the work forward, also was a mechan- 
ical engineer. 

Brown had made the statement that it was the equatorial 
bulge of the globe that stabilized it with reference to the axis 
of rotation; he had compared it to the rim of a flywheel. I 
found that this statement was disputed by some physicists. 
The physicists suggested that the stability of the earth on 
its axis was not owing to the centrifugal effect of the rota- 
tion of the equatorial bulge alone, but to that of the rotation 
of the entire mass of the earth. Later I discovered a passage 
in Coleman that appeared to express their point of view: 

It may be suggested that the earth is a gyroscope, and, as such, has 
a very powerful tendency to keep its axis of rotation pointing con- 
tinuously in the same direction. Any sudden change in the direction 
would probably wreck the world completely (87:263). 

I wished to obtain a clear statement of the rights of this 
matter. Accordingly, I corresponded with specialists, who 
eventually referred me to the works of James Clerk Max- 
well, in one of whose papers I found the following statement 
in support of Brown's position: 

. . . The permanence of latitude essentially depends on the in- 
equality of the earth's axes, for if they had all been equal, any altera- 
tion of the crust of the earth would have produced new principal 
axes, and the axis of rotation would travel round about those axes, 
altering the latitudes of all places, and yet not in the least altering 
the position of the axis of rotation among the stars (296:261). 

For the word "axes" in the second line we may read "diame- 
ters," and of course Maxwell is referring to the inequality 
of the polar and equatorial diameters, that is, to the existence 
of the equatorial bulge, to which, therefore, he directly at- 



CAMPBELL'S MECHANISM 367 

tributes the stability of the earth on its axis of rotation. 

Maxwell, in the foregoing passage, suggests that in the ab- 
sence of the equatorial bulge, any change in the crust (mean- 
ing, it is clear, the creation of any protuberance or excess 
weight at any point) would change the position of the planet 
on the axis of rotation. Even before I located this passage in 
Maxwell, a peculiar device designed by Brown had made this 
principle clear to me by observation. This device consisted 
of a globe mounted on three trunnions in such a way that it 
could rotate in any direction. The globe was a perfect sphere 
and had no equatorial bulge. It was suspended by a string 
to an overhead point. To rotate this sphere, all that was 
necessary was to wind it up and then let it go. Brown had a 
weight attached to the South Pole of the sphere, and it was 
observable that, as soon as the sphere began to rotate rapidly, 
the weight was flung to the equator, where it stabilized the 
direction of rotation as long as the speed of rotation was 
maintained. Later Campbell made a larger model of Brown's 
device, which I rotated unweighted, and I observed that it 
had no stable axis of spin. Two motions were observable: a 
rapid rotation, and a slow, random drifting. It was evident 
that the mass of the sphere acted as a stabilizer of the speed 
of rotation, but had no influence on its direction. This ex- 
periment, strongly confirming Brown's claim, encouraged me 
to persist until I could find positive theoretical confirmation 
of the observation, which eventually I did in the works of 
Maxwell. 

I was amazed and chagrined in this connection to note a 
phenomenon which, nevertheless, is as old as science itself. 
The professors most of them, at any ratewould not come to 
see the device. 

Perhaps I should describe this device in greater detail. 
A trunnion is like a ring or a hoop, made of metal. A globe 
is mounted in this trunnion on two pivots set into the ring 
at points opposite each other (180 degrees apart). Then, if 
the ring is held (as it often is on a model globe) by a pedi- 
ment or stand, the globe will rotate. Its axis will be deter- 



368 EARTH'S SHIFTING CRUST 

mined by the fixed positions of the pivots set into the ring. 

Now, if, instead of fixing the ring into a stand, or pedi- 
ment, we set it into another, larger ring, by inserting two 
pivots into the larger ring at two points at right angles to 
those of the inner ring, we have an axis within an axis, and 
the globe can be made to rotate in either direction. If a third 
ring is used, then the globe has freedom of action in any 
direction whatever. 

There is still the problem of imparting momentum to this 
globe. Since it has no fixed axis, this is a difficult problem. 
Brown solved it by suspending the device to the ceiling by 
a string attached to the outermost trunnion. This string 
could be wound up by rotating the outermost trunnion in 
one direction by hand for a while, just as a boy may wind 
up the rubber bands used to give momentum to a toy air- 
plane. Then, when the trunnion is released, the string un- 
winds, putting the globe itself in rapid rotation, but a free 
rotation, one not confined to a fixed axis. 

In view of continued skepticism, I could not be entirely 
satisfied by the Maxwell statement, supported though it 
might be by the demonstration. Since I am not myself a 
physicist, I felt it not unlikely that some persons would con- 
clude that, in the first place, I had misunderstood Maxwell, 
and that, in the second place, I was incapable of interpreting 
correctly the evidence of my eyes. I therefore wished to ob- 
tain an authoritative interpretation of Maxwell's statement, 
and, accordingly, I wrote Dr. Harlow Shapley, the Director 
of the Harvard Observatory, as follows: 

After a year of intensive work with a group of people here, I have 
concluded that the work we are doing is dependent upon a clear 
answer to the question as to whether the geographical poles are stabi- 
lized by the momentum of rotation of the earth, or solely by that of 
the equatorial bulge. I have had discussions about this with Dr. 
Adams of the Coast and Geodetic Survey, and with Dr. Clemence of 
the Naval Observatory. They have given me references to the work 
of Clerk Maxwell and others, without quite satisfying me. I am not, 
of course, equipped to understand all of the technicalities, but I am 



CAMPBELL'S MECHANISM 369 

hoping that you can give me a steer in nontechnical terms on the gen- 
eral concepts. 

My hunch is that, contrary to a widespread impression, it is the 
bulge alone that stabilizes the geographical poles. As I reason it out, 
if the earth were a perfect sphere, the energy of its rotation, derived 
from its mass in motion, would "stabilize" the speed of the rotation, 
but would have no reference to its direction. If we suppose that some- 
body could reach out from Mars with a pole, and give the earth a 
strong push at an angle of 90 from the direction of rotation, the 
earth would be shifted on the axis of rotation to an extent de- 
termined by the ratio of the force of the push to the mass of the 
earth. In fact, if the earth had no bulge, it would never have stable 
poles, but would rotate every which way. . . . 

If my view of the matter is sound, important consequences follow, 
but I am not quite certain of the validity of my premises. 

Dr. Shapley's reply, dated February 2, 1951, was, in part, 
as follows: 

Dr. [Harold] Jeffreys was fortunately here at the Harvard Ob- 
servatory and I could turn over your inquiry to him. I now have his 
reply. He says in effect that the fullest discussion of the points men- 
tioned by you is in Routh's Rigid Dynamics, probably in volume I. 
Most textbooks of rigid dynamics will have something about it. The 
theory goes back to Euler. Really both the rotation and the equa- 
torial bulge are needed to maintain stability. Without rotation the 
body could be at rest at any position; with rotation but without the 
equatorial bulge it could rotate permanently about an axis in any 
direction. . . . (343). 

With this statement I decided to rest content. It seemed to 
me that Brown's position in the matter was correct. Maxwell 
showed both by the use of his dynamical top and theoretically 
what Brown showed by his device: that a rotating sphere 
tends to throw the heaviest weights on its surface to the 
equator of spin. Maxwell and, after him, George H. Darwin 
recognized that the equatorial bulge of the globe stabilized 
the direction of the earth's rotation just as a weight on the 
surface of a model sphere would do when the sphere was 
rotated rapidly. 

Yet there is a distinct difference between the earth and 
the model globe. The earth's approximately round shape is 



370 EARTH'S SHIFTING CRUST 

not due to the fact that it is a strong, rigid body, for it is not. 
Its roundness is due primarily to the force of gravity, which 
in fact holds the earth together. The earth as a whole is a very 
weak body, and if it were not for the effect of gravity the cen- 
trifugal effect of the rotation would disrupt the earth and 
send all its component masses hurtling outwards into inter- 
stellar space. 

There is also a difference between the equatorial bulge of 
the earth and a weight attached to the surface of a model 
globe at its equator of spin. This difference consists in the 
fact that the earth's equatorial bulge and the flattenings at 
its poles have been produced by the yielding of the earth's 
body in response to the centrifugal effect of its rotation. The 
amount of the yielding has been determined by the ratio of 
the forces of rotation and gravity. The shape of the earth 
thus represents a balance of these two forces, a balance that 
is perfect, theoretically, at every point of the earth's surface. 
It therefore follows that any unit of material in this balanced 
surface will be at rest. For this reason, such a surface has 
been called an equipotential surface. 

The balance of the forces of rotation and gravity at every 
point of the earth's surface can be understood also in this 
way. The shape of the earth, as we have pointed out, is ob- 
late. This means that as you go toward the equator you are 
getting farther from the earth's center. In a sense, therefore, 
you are going uphill. Likewise, when you are going toward 
the poles you are getting closer to the earth's center and 
therefore you are going downhill. But we can all see that 
it takes no more energy to move toward the equator than it 
does toward a pole. Also, water in the ocean does not run 
downhill toward the poles. The earth's surface acts as if it 
were perfectly level. The reason for this is that as you go 
toward the equator, going uphill, the centrifugal effect of 
the earth's rotation increases just enough to compensate for 
the gradient, while, if you move toward the poles, the cen- 
trifugal effect declines in proportion. The forces of gravity 
and rotation are therefore balanced, and no centrifugal e- 



CAMPBELL'S MECHANISM 371 

feet will tend to propel a mass in this equipotential surface 
toward the equator, and no gravitational effect will tend to 
propel it toward the poles. The fact that the force of gravity 
is absolutely much greater than the centrifugal effect of the 
rotation is shown by the fact that the flattening of the earth 
is very slight. The equatorial bulge amounts to 6.7 miles in 
comparison with the earth's mean radius of 4,000 miles. This 
is a ratio of only .017 per cent. 

The past century has been notable for extensive studies 
of the effects of gravity at the earth's surface. The theory of 
isostasy has been developed, and the actually existing state of 
balance of the surface features of the earth's crust has been 
measured in various ways and for various purposes. As we 
have seen, there are various difficulties with the theory of 
isostasy, some of which may be soluble in terms of the theory 
presented in this book. At the same time, but independently, 
studies of centrifugal effects at the earth's surface have been 
undertaken. Eotvos investigated the centrifugal effects that 
would arise if a given mass had its center of gravity above 
the equipotential surface. This could occur even with masses 
in isostatic equilibrium. To visualize this case, we may take 
the example of a block of ice floating in water. 

Ice is lighter than water. When a block of ice falls into 
a body of water it displaces its own weight of water, and 
then floats with a tenth of its mass above the water level. It 
is now in equilibrium, or in isostatic adjustment, even 
though its upper part projects a considerable distance up out 
of the water. This upper tenth, in the meantime, has dis- 
placed air, not water. It is a solid mass of far greater density 
than the air it has displaced. Its center of gravity, midway 
between its summit and the water surface, is farther from 
the axis of rotation of the earth than was that of the mass 
of water it has displaced. Since points move faster with the 
earth's rotation the farther they are from this axis, this mass 
has now been given added velocity. Added velocity means 
an increase in the centrifugal effect, and one not compensated 
by gravity, since the amount of mass is the same as before, 



372 EARTH'S SHIFTING CRUST 

and therefore the effect of gravity at that point has not been 
altered. A tangential component of this added centrifugal 
momentum will tend to move this ice mass toward the 
equator. 

Eotvos applied this same principle to parts of the earth's 
crust. We have seen that, according to the theory of isos- 
tasy, mountains and continents are elevated above the ocean 
bottoms because they are composed of lighter materials, and 
they are considered to be ' 'floating" in an approximate gravi- 
tational balance with the heavier crustal formations under 
the oceans. Eotvos considered the centrifugal effects that 
might arise from the elevations of the centers of gravity of 
continental formations above those of the oceanic sectors of 
the crust, and calculated them mathematically. He found 
that the effects were comparatively slight. Attempts have 
been made to account for the drift of continents through 
these effects, but his calculations show they are too small to 
have considerable effects. Since Eotvos' time, it has been 
generally assumed that any centrifugal effects that were to be 
considered in relationship to the earth's crust must be ef- 
fects resulting from variations in the vertical position of cen- 
ters of gravity of masses in gravitational balance, that is, ele- 
vations of these centers above the equipotential surface, or 
depressions of them below it, owing to differences in relative 
density of the masses involved. 

Let us now consider, in connection with this, the effect of 
departures of given masses from the state of isostatic or gravi- 
tational equilibrium. We have already seen that there are 
remarkable departures from isostatic balance, some resulting 
from deformities of the crust, and some, it seems, from the 
accumulation of icecaps. In these irregularities in the dis- 
tribution of matter, resulting from the limited failure of 
isostatic adjustment, we must recognize the existence of an- 
other surface of the earth, in contradistinction to the equipo- 
tential or geoidal surface already mentioned. We may call 
this surface the gravitational surface, or the surface of equal 
mass. This is a real surface. It is not, however, the visible 



CAMPBELL'S MECHANISM 373 

surface. A high plateau may represent an area of deficient 
mass, and an ocean basin may represent an area of excess 
mass. We have seen that there are many oceanic areas that 
show positive isostatic anomalies, or the existence of local 
excesses of mass in the earth's crust. We can easily see the 
distinction between the level equipotential surface of the 
geoid, represented by sea level, and the surface of mass that 
may deviate considerably from the level surface. 

The mechanism for crust displacement presented in this 
book depends upon recognition of the fact that distortions of 
mass on the earth's surface, of whatever type, if they consti- 
tute anomalous additions of mass at points on the earth's 
surface, will give rise to centrifugal effects like the effect of 
the mass attached to the surface of Brown's rotating model 
sphere, in accordance with ordinary principles of mechanics, 
and measurable by the standard formula for calculating 
centrifugal effects. 

An example may serve to illustrate the difference between 
the surface of mass, which differs in elevation from place to 
place, and the equipotential, geoidal surface. Let us take a 
fictional case of a mass out of isostatic adjustment but with 
its center of gravity below the surface of the geoid. Let us 
suppose that under the bottom of the Atlantic Ocean we 
have a slab of material ten times as dense as basalt, two thou- 
sand miles long, one thousand miles wide, and forty miles 
thick. The excess of mass in this slab, as compared with other 
sectors of the crust, would be enormous, and gravity would 
be greater at the surface. Consequently, the ocean level over 
this area would be affected slightly, but the shape of the geoid 
would not be significantly changed, and the sea level would 
still represent an equipotential surface. The center of grav- 
ity of the anomalous mass of high density would be depressed 
far below sea level; it might be fifteen or twenty miles below 
the geoidal surface. Now if the slab were of average density, 
the depression of the center of gravity would mean an in- 
verse Eotvos effect, that is, a poleward centrifugal effect, the 
quantity of which, as we have seen, would be slight. But, now, 



374 EARTH'S SHIFTING CRUST 

to counteract this, the rotation of the earth, acting on this 
mass of ten times normal density, would produce a centrifu- 
gal effect ten times as great as the one normally balanced at 
that point by the effects of gravity. Let us note the fact that 
the assumption that this slab is not isostatically compensated 
involves the consequence that the centrifugal momentum 
resulting from it is not compensated. 

The difference between an Eotvos effect and one produced 
by an uncompensated mass may be illustrated in another 
way. Let us return to our example of a mass of ice. Campbell 
has suggested the example of an iceberg before and after its 
separation from its parent, land-based icecap. It is assumed 
that the icecap is uncompensated. The iceberg, breaking off 
from the icecap, falls into the water. Before this event the 
icecap, by assumption, is outside the equilibrium surface of 
the geoid; the rotation of the earth acts upon it precisely as 
the rotation of Brown's model sphere acts upon the weight 
fixed to its surface. 

But let us see what happens when the iceberg falls into 
the sea. It now reaches gravitational equilibrium. It sinks, 
and displaces its weight in water. It is now a part of the equi- 
potential surface of the geoid (though the portion projecting 
above sea level is not, and therefore exerts an Eotvos effect). 

Now what is the quantitative relationship between the 
Eotvos effect and the original centrifugal effect of the ice- 
berg? It is plain that now nine tenths of the ice is within 
the equilibrium surface. For this nine tenths of the mass the 
equatorward centrifugal momentum produced by the earth's 
rotation is precisely cancelled by the poleward component of 
the force of gravity at that point, so that there is no net cen- 
trifugal effect. Only one tenth of the ice remains to exert an 
effect, and the quantity of this effect, furthermore, is de- 
termined by the elevation of the center of gravity of this 
tenth of the iceberg above sea level. But the elevation has 
been enormously reduced. It has, in fact, been reduced to one 
tenth of the elevation of the center of gravity before the fall 
of the iceberg into the sea. Campbell has pointed out that, 



CAMPBELL'S MECHANISM 375 

as a result, the centrifugal momentum not compensated by 
gravity has now been reduced to one one hundredth of the 
quantity of the effect of the ice mass when it was totally 
uncompensated. 

It appears, therefore, that the question as to whether a 
mass is in isostatic adjustment or not is the essence of the 
matter. The icecap, if totally uncompensated, may produce 
a centrifugal effect one hundred times the Eotvos effect for 
the same mass; furthermore, it may be calculated by the 
formula used by Campbell, with the reservation that a small 
poleward component of gravity caused by the oblateness of 
the earth and proportional to the degree of the oblateness 
must be taken into consideration. 

Let us attempt to define and clarify this poleward compo- 
nent of the force of gravity, and to estimate its probable rela- 
tive magnitude. It applies both to masses in equilibrium but 
with elevated centers of gravity, and to any mass resting on 
the earth's surface but uncompensated. Its effect will be 
greater in the latter case than in the former. In both cases it 
will tend to counteract the equatorward component of the 
centrifugal effect of the icecap. 

The poleward component of the force of gravity results 
from the oblateness of the earth. It may be visualized as fol- 
lows: if you should place a marble at the equator, and if the 
rotation of the earth should be interrupted so that the earth 
would be at rest, then the marble would tend to roll toward 
one of the poles, because the poles are closer to the center of 
the earth, and therefore downhill. As I have mentioned, this 
applies both to masses out of isostatic equilibrium, and to 
those in equilibrium, but with elevated centers of gravity 
(that is, to masses standing higher because of their lesser aver- 
age density). However, as I have pointed out, there will be a 
quantitative difference between the poleward effects of gravity 
in these two cases of about 100:1. 

In both cases these effects would tend to counterbalance 
the equatorward component of the total centrifugal effect of 
the icecap. The question is: What proportion of the equator- 



376 EARTH'S SHIFTING CRUST 

ward effect would be thus counterbalanced? This is the crux 
of the matter. 

The answer to this problem may be found in the following 
consideration. The force with which any object rolls down- 
hill is proportionate not only to its weight but to the gradient 
of the slope. On a flat surface the marble is at rest. It would 
develop maximum momentum if it could fall straight down 
toward the earth's center (if the surface were vertical). Be- 
tween these extremes of zero and maximum momentum there 
must be an even curve of increasing momentum with increas- 
ing gradient. (It would follow, of course, that a sled would 
develop twice the momentum if going down a hill twice as 
steep.) 

To apply this principle to the icecap, we may observe that 
if there were no oblateness to the earth, there would be no 
poleward component of gravity. If, on the other hand, the 
oblateness were increased to the point where the icecap could 
fall straight down, it would develop maximum momentum, 
the product of its velocity and of its weight. Between these 
extremes, the poleward momentum would be proportional to 
the gradient. We have seen, however, that this gradient 
amounts to only .017 per cent. It follows from this that the 
poleward component of gravity acting on the icecap will be 
.017 per cent of the tangential component of the centrifugal 
effect of the icecap. This of course is a relatively negligible 
quantity. 

It may be objected that in this discussion we have offered 
no mathematical calculations in support of the positions taken, 
and that therefore we have no quantitative basis for our the- 
ory. This is, however, a misunderstanding. It is essential, be- 
fore mathematical computations are made, to understand the 
assumptions on which they are based. In our correspondence 
we have more than once received communications in which 
the authors have indirectly or directly stated that the question 
as to whether a given mass was or was not isostatically com- 
pensated was irrelevant. It has seemed to us, on the other hand, 
that the actual balanced surface or shape of the earth as de- 



CAMPBELL'S MECHANISM 377 

termined by the balance of gravity and the centrifugal effect 
of the rotation that is, the geoid, or the equipotential surfaces 
while perfectly valid as an assumption for many calcula- 
tions, was irrelevant for our problem. We feel it must be 
conceded that if the conformity of the earth's materials in 
general to the balance of the two forces of gravity and rotation, 
so as to create the oblate shape of the earth the geoid is im- 
portant, the failure of some of the materials to conform to 
this shape is also important. By definition, a mass that is not 
isostatically compensated fails to conform to this shape. Thus 
the real surface of mass differs from the geoid, and cannot 
be called an equipotential surface. We feel that the real "sur- 
face of mass" of the earth cannot be disregarded. 

In this situation equations are of no use. They will not help 
us attain clarity. What is needed instead is a re-examination 
of the assumptions on which equations have been made. This 
is an intellectual problem of the logical development of ideas, 
and corresponds to the process advocated by Maxwell as supe- 
rior, in some situations, to calculations. Discussing the intri- 
cacies of the mechanics of rotation before the Royal Society, 
Maxwell remarked: 

... If any further progress is to be made in simplifying and 
arranging the theory, it must be by the method that Poinsot has re- 
peatedly pointed out as the only one that can lead to a true knowl- 
edge of the subject that of proceeding from one distinct idea to an- 
other, instead of trusting to symbols and equations (296:24811). 

Let us remember that the author of this remark was one 
of the greatest mathematical physicists of all time. As such, 
he understood the limitations of mathematics, of which the 
most essential is that all calculations must be based in the 
last analysis on assumptions that consist of clear ideas, logically 
expressible in words. 

I do not wish to have it seem, however, that I am conced- 
ing the point that Mr. Campbell and I have not provided 
quantitative solutions. On the contrary, I believe that, on the 
basis of the assumptions discussed above, Mr. Campbell has 
provided sound and adequate (though approximate) quanti- 



378 EARTH'S SHIFTING CRUST 

tative estimates for the equatorward component of the cen- 
trifugal effect of the icecap, and furthermore, that he has 
indicated the correct order of magnitude of the bursting 
stresses that may be produced in the crust. 



XII : CONCLUSION 



i. Looking Forward 

It is said that a sound scientific hypothesis should have the 
character of predictability. "Predictability" is said to apply 
to a hypothesis if the hypothesis predicts the discovery of new 
facts that later are actually discovered. An example of pre- 
dictability of this sort was the discovery some years ago of 
Pluto as the result of calculations based on the theory 
of gravitation. Our theory has repeatedly shown that it pos- 
sesses this sort of predictability. On one occasion Campbell 
worked out, from purely theoretical considerations, the pat- 
terns of crustal fractures that would be formed by a dis- 
placement. At the same time, in a different city and entirely 
independently of him, I was discovering, in the works of W. 
H. Hobbs, geological evidence showing that fracture pat- 
terns of precisely this kind actually existed in the rocks. 
Only later did we compare results. If I had started with his 
drawings and used them to guide my research in the field, 
I would have found approximately the fracture patterns that 
he predicted, and I would have found them sooner. On 
another occasion when, in 1951, radiocarbon dates showed 
the very recent end of the North American ice sheet, I 
reached the conclusion from the theory that the begin- 
ning of that glaciation must have been quite recent, and 
much more recent than generally believed. At that time 
this conclusion could not be tested, because the range o 
the radiocarbon method was not great enough. However, 
I was aware of the fact that several scientists were work- 
ing on the problem of extending the range, and I confidently 
looked forward to a confirmation of the theory when and if 
the range was extended. I had to wait only until 1954, when 
Horberg, as already mentioned, published results showing 



380 EARTH'S SHIFTING CRUST 

that the icecap had entered Ohio only 25,000 years ago. 
Again and again we have had experiences similar to this. 
Campbell has, in fact, suggested that the theory may have 
economic importance because of the fact that it may give 
us a tool through which we may attain more reliable infor- 
mation about the hidden structures of the earth's crust, and 
thus be able to locate valuable minerals. It seems to me 
quite possible that his hope will eventually be realized. 

Our theory appears to have another kind of predictability. 
It is possible that it can tell us something about the rela- 
tively near future of the earth. The evidence appears to sug- 
gest that displacements have occurred at short intervals. 
Since what has happened in the past may be expected to hap- 
pen in the future, it is quite reasonable to ask when another 
movement may be expected. There are a number of factors 
that bear on this, and they are worth discussing even though, 
when we get through, we may carry away the feeling that our 
speculations may contain more imagination than substance. 

It would appear from the evidence I have presented that 
the intervals between the beginnings of the last three dis- 
placements were about 40,000 years in length. It seems, also, 
that the last movement began between 26,000 and 17,000 
years ago. If these assumptions are correct, and if the average 
of these movements holds for the future, it seems that the 
next displacement of the crust should not be expected for 
another 10,000 or 15,000 years. While this is a reassuring 
thought, it should be kept in mind, however, that there are 
a number of unknown factors in the situation, and that there 
is no reason to believe that the average of the last three dis- 
placements tells us anything about the limits of variation in 
the periods between displacements. On the contrary, the 
conclusion to be reached from the investigation completed in 
this book is that the periods between displacements may 
vary considerably. 

A number of factors favor a movement somewhat sooner 
than the time indicated by the average of the last three dis- 
placements. Among these, I may mention the fact, empha- 



CONCLUSION 381 

sized by Brown, that the present Antarctic icecap is larger 
than the last North American icecap. If Campbell's calcula- 
tions are close to the truth, it seems that the bursting stresses 
in the crust may now be close to the critical point, from this 
source alone. Yet there is also a possibility that the centrifu- 
gal effect of the Antarctic icecap may at the present time be 
supplemented by another significant centrifugal effect cre- 
ated by the icecap in Greenland. It is true that the Greenland 
cap is much smaller than the one in Antarctica, but, on the 
other hand, its center is much farther from the pole. For 
this reason it could conceivably have an important centrifu- 
gal effect. Its position on the meridian is such that any un- 
compensated mass would add to rather than counteract the 
effect of the Antarctic cap; the two icecaps are, so to speak, 
in tandem. 

In recent years a French polar expedition has taken many 
gravity readings across the top of the Greenland icecap. The 
purpose of these readings was to assemble data for a deter- 
mination of the state of isostatic adjustment of the Greenland 
cap. The results of this piece of research are instructive for 
the whole subject of isostasy. They can be read two ways. On 
the one hand, the gravity data when reduced according to 
one of the formulas in common use the Faye-Bouguer - 
showed an enormous excess of mass in Greenland (441:60- 
61); on the other hand, the same data, when reinterpreted 
differently, resulted in a finding of good isostatic adjust- 
ment. It is important to realize that the different methods 
of reducing gravity data are based on varying assumptions 
regarding the deeper structure of the earth's crust, and that 
these assumptions are not subject to direct confirmation. 
Daly at one time remarked that he did not believe that any 
of the different methods of evaluating gravity data came very 
near the actual truth. It is reasonable to think that the se- 
lection of assumptions in this field may be influenced by a gen- 
eral belief in the soundness of isostasy, and that this general 
belief will lead to a preference for those assumptions that 
result in findings of close isostatic adjustment. It is perhaps 



382 EARTHS SHIFTING CRUST 

on account of this that Einstein regarded the theory of isos- 
tasy as itself unreasonable (128). According to our theory, 
Greenland possibly was deglaciated during the period of the 
Wisconsin icecap in North America, and therefore the ice- 
cap there may be recent, and isostatic adjustment poor, 

There are a few indications that the pressure of the Ant- 
arctic cap (possibly reinforced by the Greenland cap) has 
already begun to disturb the stability of the earth's crust. 
These consist of recent seismic movements. 

In the study of earthquakes, specialists have distinguished 
between them not only according to their scale but also by 
a qualitative difference that appears to exist between those of 
minor and those of major magnitudes. Minor earthquakes, 
which occur daily in considerable numbers, are considered 
to be of local origin. They are merely episodes in the per- 
petual process of adjustment of strains in the earth's crust 
arising from local causes. 

Some of the major earthquakes, on the other hand, are 
considered to be qualitatively different. Benioff, for example, 
suggests that these major earthquakes are not related to local 
causes of any sort, but result from the operation of what he 
calls "world-wide stress systems" (29) in other words, from 
pressures applied to the earth's crust as a whole. So far as I 
know, no geologist has advanced an explanation for these 
world- wide pressures; it seems quite possible that they may 
be related to the icecap pressure that, according to our view, 
has been increasingly exerted on the crust for thousands of 
years. 

Benioff draws attention to a fact that appears to confirm 
this supposition. He points out that in recent decades there 
has been an increasing tempo of major earthquakes; they 
appear to be coming closer together and increasing in vio- 
lence. He cites especially the great quakes of 1904, 1924, 
1 935> 1 94> an d 1950 (29:335). If the Antarctic icecap is the 
major cause of these quakes, we can understand the increase 
in their frequency and intensity, which may result either 
from the increase of the quantity of Antarctic ice or from 



CONCLUSION 383 

the progressive weakening of the crust under the repeated 
major shocks. 

Some further confirmation of this suggestion may be found 
in some specific features of the two greatest of the major 
earthquakes, those of eastern India in 1897 and in 1950. The 
earlier of these was a cataclysm that involved hundreds of 
thousands of square miles. The later one was still more vio- 
lent, in line with the observation made by Benioff. The 
reader may note, by glancing at the globe, that the area in 
which these two quakes occurred lies almost on the meridian 
of 96 E. Long., which, it appears, is the meridian of direct 
thrust of the Antarctic icecap. According to our theory, this 
is the meridian along which the gradually increasing thrust 
of the Antarctic icecap has been exerted for thousands of 
years. Let us note the fact that Assam lies across the equator 
from the South Pole, and that the thrust of the icecap would 
tend to push the area toward the north, or poleward, so that, 
because of the shape of the earth, the result would be com- 
pression of the crust in that area. Now it is not unreasonable 
to suppose that during several millennia the pressure from 
Antarctica may have resulted in some elastic yielding of the 
crust along the meridian, with consequent concentration of 
compressive stresses in that area. 

I cannot say that the constant pressure of the Antarctic 
icecap, operating on the crust in the same direction for ten 
thousand years or more, and amounting to several times 
a million times a million tons, definitely did cause some 
yielding of the crust in that direction, because I do not know, 
but I know what would have happened if there were some 
yielding. Yielding, at the latitude of Assam, to a pressure 
directed from the south would mean compression of the 
crustal material between lateral pressures, because of the 
lesser circumference of the globe as one goes north. If we 
suppose only a very slight yielding of the crust along the 
meridian (amounting to only a few feet) the pressures so 
produced would be very great. An explosive situation would 
exist because rock is not very compressible. The forces would 



384 EARTH'S SHIFTING CRUST 

have to express themselves somehow. There would be no 
place to go but up. A striking confirmation of this may be 
found in the extraordinary fact that Mt. Everest and pos- 
sibly much of the Himalayan range appear to have been 
raised from 100 to 200 feet by the gigantic earthquake of 



Now we learn from Daly that gravitationally the Hima- 
layas are already too high. They are, or were before the 
earthquake, over 700 feet higher than they should have 
been for good isostatic adjustment. Earthquakes are generally 
supposed to perform the function of enabling the crust to 
adjust to the force of gravity. If an area stands too high, 
earthquakes occur during a process of settling down to 
equilibrium. If an area is too low, earthquakes may occur as 
it is rising. But what shall we say about an earthquake that 
finds an area already too high, and shoves it up further? 
This earthquake is not behaving according to the rules. It 
is not tending to establish the stability of the crust, but rather 
is exposing the crust to a situation of increased strain after 
the quake. 

But most important of all, where could the compressive, 
horizontally directed force have come from to cause this 
earthquake? The best reason for putting forth the claims of 
the Antarctic icecap is that, so far, no one has produced a 
more reasonable suggestion. It is interesting that the editors 
of Life, in their illustrated account of the great quake in 
Assam, called it "the most mysterious earthquake of mod- 
ern times/' 

There are a few additional items that appear to fit into 
this picture. In the very year in which the Assam earthquake 
occurred (1950) another great earthquake on the same merid- 
ian, but on the opposite side of the earth, virtually destroyed 
the city of Cuzco. Also near the same meridian, in Mexico, 
we have recently seen the rapid creation of the great new 
volcanic mountain of Paricutfn, an event that Campbell 
ascribes to the effects of the increasing bursting stress on the 
crust in the earth's equatorial bulge. Finally, it may be worth 



CONCLUSION 385 

while to mention Ewing's recent discovery of a world-wide 
system of great submarine canyons, along which the crust is 
technically active. Observers have suggested that these can- 
yons are still widening. Breen has pointed out that their pat- 
tern (not yet fully established) is consistent with the effects 
of a force attempting to pull the Western Hemisphere south- 
ward (44). 

I am aware that the items that I have mentioned above 
may all be explained someday according to other principles, 
and may in fact have nothing to do with centrifugal effects 
from Antarctica. However, I feel that a definite chance exists 
that the phenomena may be related, and that they may indi- 
cate that beginning of a crust displacement is not remote. The 
question therefore arises as to whether, in case of another 
displacement, it is possible to predict anything about it in 
detail. Among the questions to which answers may be sought 
are those of the precise direction the displacement may take, 
and the total distance it may cover. 

As to the first question, our theory offers us the basis for 
a reasonable estimate. If our finding of the location of the 
center of mass of the Antarctic icecap is correct, and if we 
assume that no other centrifugal effects from anomalies in 
the crust will be acting to deflect the motion, we may expect 
the next displacement to be in the direction of 96 E. Long, 
from the South Pole. This would involve another southward 
displacement of the Western Hemisphere, together with an- 
other northward displacement of East Asia. 

A guess as to the magnitude of the next displacement re- 
quires the correct assessment of a number of rather impon- 
derable factors. We should expect the crust to continue to 
move until the Antarctic icecap was largely destroyed. This 
might take longer than it did in the case of the North Amer- 
ican icecap, because the Antarctic icecap is larger. On the 
other hand, it could take less long, because in the case of 
Antarctica there is no land available for the rearward build- 
up of the icecap as it moves into the lower latitudes, such as 
seems to have occurred in North America. Perhaps we shall 



386 EARTH'S SHIFTING CRUST 

have to be satisfied, for the present, with the guess that the 
next displacement may be of roughly the same magnitude as 
the last one. 

If these guesses turn out to be correct, the next North Pole 
will be in the vicinity of Lake Baikal, in Siberia. North 
America, moving southward into the tropics, will subside 
some hundreds of feet relatively to sea level, and the ocean 
will occupy the river valleys and will divide the continent 
into several land areas. India will move northward out of the 
tropics, and since there will be no land to the south to pro- 
vide a refuge for the fauna and flora, we shall have to expect 
the extinction of many species of animals and plants now 
confined to that country. Many other consequences may be 
unpredictable. The gradual climatic changes due to changing 
latitude will be accompanied by numerous sudden, violent, 
and destructive climatic changes due to volcanism. 



2. A General Summary 

In this book I have presented a highly detailed mass of mate- 
rial, and I have sought to relate it to a single, essentially 
simple hypothesis. It now remains to summarize the evi- 
dence, and the argument for the hypothesis. 

We have seen that the problem of the geographical stabil- 
ity of the poles has long been a vexatious matter for science. 
From time to time theories of polar shift have been advanced, 
supported by large quantities of evidence, but the proposed 
mechanisms have been found defective, and in consequence 
the theories have been rejected. The failure of the theories 
has led, in the following years, to neglect of the evidence, or 
to its analysis in accordance with theories conforming to the 
doctrine of the permanence of the poles. Although all the 
older theories of polar change, including that of Wegener, 
have been discredited, the evidence in favor of polar change 
has constantly increased. As a consequence, many writers at the 



CONCLUSION 387 

present time are discussing polar shift, but none of them has 
as yet suggested an acceptable mechanism. 

The general evidence for displacements of the crust is ex- 
ceedingly rich. In turn, the assumption of such displacements 
serves to solve a wide range of problems, such as the causes 
of ice ages, warm polar climates, mountain building; it pro- 
vides a mechanism that may account for changes in the eleva- 
tions of land areas and in the topography of the ocean floors; 
it also provides a basis for the resolution of conflicts in iso- 
static theory. For the period of the late Pleistocene, the theory 
permits the construction of a chronology of polar shifts, with 
three successive tentative polar positions in Alaska, Green- 
land, and Hudson Bay preceding the present position of the 
pole. The evidence for the location of the Hudson Bay 
region at the pole during the last North American ice age is 
overwhelming, and this fact in itself provides the principal 
support for the assumption of the earlier shifts. The tempo 
of change indicated for the late Pleistocene is reflected in 
evidence from earlier geological periods. 

The theory is able to explain not only the general succes- 
sion of climatic changes in various parts of the world in the 
late Pleistocene; it can account also for the detailed history 
of the last North American icecap. It can explain the fluctua- 
tions of that icecap, its repeated retreats and readvances. It 
shows that the effects of volcanism were directly responsible 
for the oscillations. It shows also that these same effects, 
added to the effects of gradual climatic change, were responsi- 
ble for the widespread extinctions of species at the end of the 
Pleistocene, and from this we may assume that the same 
cause was responsible for numerous extinctions in earlier 
geological periods. By providing a reasonable basis for the 
assumptions of rapid climatic change and rapid topograph- 
ical change (including the existence of former continents and 
land bridges), the theory provides solutions for many prob- 
lems in the evolution and distribution of species. 

Our theory of displacement depends upon two assump- 
tions, and on two only. One of these is that a continental ice- 



EARTH'S SHIFTING CRUST 

cap is largely or entirely uncompensated isostatically. The 
other assumption is that at some point below the crust a weak 
layer exists that will permit the displacement of the crust 
over it. The first assumption is capable of verification, and 
may even be verified in the course of the current Geophysical 
Year. This will depend, however, on whether the new gravity 
data that are to be collected during this year are reduced by 
formulas based on correct assumptions. There is no present 
prospect of direct verification of the second assumption. 
However, the body of geological evidence presented in this 
book provides very strong indirect support for both these 
assumptions. 

As to the mechanics of crust displacements, Campbell has 
provided the necessary constructions. To some, the simplicity 
of his thought may be unnerving, but I feel assured that in 
the end this simplicity itself will be the justification for re- 
posing wide confidence in this theory. For it appears that no 
recondite principle can vitiate it. Who can argue with for- 
mulas so simple that a high school student can, and usually 
does, master them? 

In addition to the support provided by evidence from the 
field, our theory receives support from logic. It has been 
recognized that one characteristic of sound new theories is 
the simplicity of their basic assumptions, and another is their 
capacity to explain a greater number of facts or a greater 
range of problems than previous theories. It was the sim- 
plicity of this theory that first aroused the interest of Einstein, 
in whose philosophy of science simplicity was a prime con- 
sideration. It appeared to him also that it might explain a 
far greater number of facts than were explainable by the 
various theories that have been produced to explain the lead- 
ing problems of the earth separately. 

I shall have to admit that the full development of the im- 
plications of crust displacements, for all the affected fields, 
has carried me much further than I originally expected. 
When I resurvey the structure that has now been erected on 
the basis of the simple basic theory, I feel exactly as Sir James 



CONCLUSION 389 

Frazer, author of the Golden Bough, felt at the end of his 
protracted labors, and I cannot do better than conclude this 
volume with his words: 

Now that the theory, which necessarily presented itself to me at 
first in outline, has been worked out in detail, I cannot but feel that 
in some places I may have pushed it too far. If this should prove to 
have been the case, I will readily acknowledge and retract my error 
as soon as it is brought home to me. Meanwhile, my essay may serve 
its purpose as a first attempt to solve a difficult problem, and to bring 
a variety of scattered facts into some sort of order and system. (The 
Magic Art) 



"But when you have the truth, everything fits. 
I think that's the main test of truth. It fits, it 
makes a harmony, one pattern all through. . . ." 

E. R. Punshon, Information Received 
(Penguin Books, 1955) 



APPENDIX 



Letters from Albert Einstein and George Sarton 

A. Einstein 
112 Mercer Street 
Princeton, N. J. 

November 24, 1952 
Mr. Charles Hapgood 
2 Allerton Street 
Provincetown, Mass. 

Dear Sir: 

I have read already some years ago in a popular article about the 
idea that excentric masses of ice, accumulated near a pole, could pro- 
duce from time to time considerable dislocations of the floating rigid 
crust of the earth. I have never occupied myself with this problem but 
my impression is that a careful study of this hypothesis is really de- 
sirable. 

I think that our factual knowledge of the underlying facts is at pres- 
ent not precise enough for a reliable answer based exclusively on 
calculations. Knowledge of geological and paleontological facts may be 
of decisive importance in the matter. In any case, it would not be justi- 
fied to discard the idea a priori as adventurous. 

The question whether high pressure may not be able to produce 
fusion of nuclei is also quite justified. It is not known to me if a quanti- 
tative theory has been worked out by astrophysicists. The action of 
pressure would not be a static effect as classical mechanics would sug- 
gest, but a kinetic effect corresponding not to temperature but to de- 
generacy of gases of high density. You should correspond about this 
with an astrophysicist experienced in quantum theory, f.i. Dr. M. 
Schwarzschild at the Princeton University Observatory. 

Sincerely yours, 
(Signed) A. Einstein 



APPENDIX 

Princeton, 
May 8, 1953 
Dear Mr. Hapgood, 

I thank you very much for the manuscript that you sent me on May 
3rd. I find your arguments very impressive and have the impression that 
your hypothesis is correct. One can hardly doubt that significant shifts 
of the crust of the earth have taken place repeatedly and within a short 
time. The empirical material you have compiled would hardly permit 
another interpretation. 

It is certainly true, too, that ice is continually deposited in the polar 
regions. These deposits must lead to instability of the crust when it is 
sufficiently strong not to constantly keep in balance by the adjustment 
of the polar regions. 

The thickness of the icecap at the polar regions must, if this is the 
case, constantly increase, at least where a foundation of rock is present. 
One should be able to estimate empirically the annual increase of the 
polar icecaps. If there exists at least in one part of the polar regions a 
rock foundation for the icecap, one should be able to calculate how 
much tune was needed to deposit the whole of the icecap. The amount 
of the ice that flowed off should be negligible in this calculation. In this 
way one could almost prove your hypothesis. 

Another striking circumstance appears in connection with the ellip- 
ticity of the meridians. If according to your hypothesis an approximate 
folding of the meridional volume takes place, that is, folding of a 
meridional volume within an equatorial volume (which is considerably 
larger), this event will have to be accompanied by a fracture of the hard 
crust of the earth. This also fits in very well with the existing phe- 
nomena of the volcanic coastal regions with their mainly north-south 
extension and the narrowness in the east-west direction. Without your 
hypothesis one could hardly find a halfway reasonable explanation for 
these weak spots of the present-day crust of the earth. 

Excuse me for not writing in English. My secretary has been away 
for some time, and "spelling" makes frightful difficulties for me. 

With sincere respect and kind regards, 

Yours, 

(Signed) A. Einstein 
(Translated by Use Politzer) 



392 EARTH'S SHIFTING CRUST 

5 Channing Place, 
Cambridge, Mass., 
Tuesday '55 06.07 
Dear Mr. Hapgood, 

I have read your lecture at the AMNH, the discussion which followed 
and the Einstein documents, with deep interest. I really think that you 
are on the right track but have no authority to express a more definite 
opinion. It is clear that the only opinions which matter are those which 
are the results of independent studies by competent specialists. 

The combination of ideas is so new that the history of science has 
nothing to contribute to its understanding. The fact that there have 
been earlier theories like those of Wegener, Kreichgauer and Vening 
Meinesz simply proves that some meteorologic and geologic problems 
had to be solved, and exercised the minds of men of science. What you 
need is not historical facts, but physical ones, and mathematical de- 
velopments. 

With every good wish 

(Signed) 

George Sarton 



GLOSSARY 

ANOMALY, Positive: An excess of mass at a point on the crust, as com- 
pared with the average distribution of mass. 

Negative: A similar but opposite condition, in which there is a 

local deficiency of mass. 
ANTICLINE: An archlike folding of rocks or rock strata so that the 

lower beds or strata are enclosed in the upper. 
ARCHAEOCYATHIDAE: A fossil sponge, at one time supposed to be 

a fossil coral. 
ASTHENOSPHERE: A layer of material below the crust; assumed to 

be weak because of heat and pressure. 
BASEMENT ROCKS: Rocks of great obscurity and complexity lying 

beneath the upper rock layers; thus, the lowermost rocks of the 

known series. 
CENTRIFUGAL FORCE: The force tending to throw a body away 

from the center, in a straight-line direction of flight. 
DECIDUOUS TREES: Trees having seasonally falling foliage (oak, 

elm, etc.) as contrasted with evergreens, having constantly renewed 

foliage (pine, etc.). 
DIASTROPHISM: The process, or processes, by which major features 

of the crust are formed through deformation, such as faults, plateaus, 

etc. 

ECOLOGICAL: Pertaining to the mutual relationship between organ- 
isms and their environment. An ecology is the place-relationship of 

life forms in their environment. 
EPEIROGENESIS (EPEIROGENY): A grander form of diastrophism, 

forming the broader features of crustal relief, such as continents, 

ocean beds, etc. 

EPICONTINENTAL: Pertaining to regions along the continental shelf. 
EUSTATIC: Pertaining to a land area which has not undergone eleva- 
tion or depression. 
GEOID: The figure of the earth (an oblate sphere) with the average sea 

level conceived of as extending throughout the continents. 
GEOSYNCLINE: A great downward flexing of the crust. 
GRAVITY, Center of: An imaginary point at which, for reasons of 

computation, the entire weight or mass of a body is imagined to be 

concentrated. 
HORSE LATITUDES: A belt in the neighborhood of 30 N. or S. Lat, 

characterized by high pressure, calms, and baffling winds. 



394 EARTH'S SHIFTING CRUST 

HYDROSTATIC: Pertaining to pressure and equilibrium of liquids. 

IGNEOUS ROCKS: Rocks which have cooled and solidified from a 
molten state. 

INSOLATION: Solar radiation received by the earth. The insolation 
curve represents the combined effects on mean world-wide tempera- 
tures of various astronomical factors, such as precession and varia- 
tions of the orbit of the earth about the sun. 

ISOSTASY: The definition is discussed in the text: Chapter VI. 

LITHOSPHERE: The outer shell of the planet. It is composed of rocks 
and the products derived from them by erosion, etc., such as gravels, 
soils, and the like. The crystalline, solid lithosphere is assumed to be 
between 20 and 40 miles thick. (Also called crust.) 

LOAD, Negative: A deficiency of matter at a given point on the crust; 
considered negative because it results in a pressure from within, as 
a result of the tendency to achieve hydrostatic balance. 
Positive: A local excess of mass. 

MAGMA: Molten rock material within the earth. When cooled and 
crystallized into solid form it yields the so-called igneous rocks (q.v.). 

MASS: A measure of the amount of matter in a body. 

MASS, Center of: Point at which the mass is assumed to be concen- 
trated; for computational purposes. 

METAMORPHIC: Altered; applied to rocks or rock strata that have 
been physically changed by heat or other means. 

MILLIGAL: A thickness of ten meters of granite; the effects (gravi- 
tational) produced by such mass. 

MUTATION: A sudden variation in the characteristics of a life form 
as compared to those of its progenitors. 

NEBULAR THEORY: A theory of the origin of the solar system, ac- 
cording to which a gaseous nebula coalesced and cooled to form 
compacted centers which then further contracted to form the 
planets. 

OOZE: A soft deep-sea deposit composed of shells, debris, meteoric 
dust, etc. Argillaceous ooze is a clayey type. 

PLANETESIMAL: A small, solid planetary body having an individual 
orbit about the sun. 

PLANETESIMAL HYPOTHESIS: A theory of the origin of the solar 
system supposing that the planets were formed by collision and 
coalescence of planetesimals and thus have never been wholly 
molten. 

PLICATION: Folding into layers or strata. 

PRECESSION: The wobbling of the axis of the earth, making the pole 
describe a circle as the planet spins. 

RADIATION, Adaptive: The production of a diversified fauna as the 
result of the availability of new ecological spaces. New faunas re- 



GLOSSARY 395 

suit from the adaptation of an original stock to the new environ- 
mental opportunities for living space. 

SIAL: Silicon-aluminum rocks. 

SIMA: Silicon-magnesium rocks. 

STRANDLINE: A line marking a fossil seashore. 

STRATIGRAPHIC: Pertaining to the arrangement of rock strata. 

TECTONIC: Pertaining to rock structures resulting from deformation 
of the crust. 

TURBIDITY CURRENTS: Submarine currents caused by slumping 
of deposits along continental margins. These currents carry sedi- 
ments with them. 

UNCOMPENSATED WEIGHT: The weight of a crustal formation not 
isostatically adjusted. It thus constitutes a positive anomaly (q.v.). 

UNIAXIAL: The condition of having only one axis, as a sphere. 

VARVES: Annual deposits of sediment. These can be counted to de- 
termine annual shorelines of old lakes. 

VIRENZPERIOD: A period in the history of a life form in which it ex- 
periences an explosive evolution and proliferation. 

VISCOSITY: The quality of being able to yield to stress or of being 
able to flow; the measure of such a property. 



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The following alphabetical list serves both as bibliography and as iden- 
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2. Anderson, E. C., Levi, H., and Tauber, H., "Copenhagen Natural 
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3. Anderson, R. J., "The Anatomy of the Indian Elephant/' Journal 
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4. Anderson, W., "Quaternary Sea-Levels in the Northern Hemi- 
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11. Anthony, Harold, "Nature's Deep Freeze." Science Digest (Jan., 
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12. Army Observer's Report of Operation Highjump, Task 'Force 68, 
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13. Arrhenius, Gustav. See Pettersson, Hans. 

i3a. Arrhenius, Gustav, "Sediment Cores from the East Pacific/' Reporti 
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14. Arrhenius, G., Kjellberg, G., and Libby, W. F., "Age Determination 
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15. Ashley, George H., General Information on Coal Mineral Resource 
Report No. 6, Part I, Geological Survey of Pennsylvania. 1928. 

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Helsinki, Finland, 1948. 

416. Tatel, H. E., and Tuve, M. A., Seismic Studies (The Earth's Crust). 
Carnegie Institution of Washington. Year Book No. 52, for the 
year 1952-1953. Annual Report of the Director. December 11, 
1953. (Reprint.) 

417. Tazieff, Haroun, Craters of Fire. New York, Harper, 1952. 

418. Technical Report of the International Conference on Rock Mag- 
netism. See Dietz, Robert S. 

419. Termier, Pierre, "The Drifting of Continents." Smithsonian Re- 
ports, 1924. 

420. Time Magazine (Dec. 26, 1949). 

421. Time Magazine (Sept. 8, 1954). 



418 EARTH'S SHIFTING CRUST 

422. Tolmachev, I. P., "The Carcasses of the Mammoths and Rhinoc- 
eroses Found in the Frozen Ground of Siberia." Transactions of 
the American Philosophical Society. New Series, v. XXIII, Pt. i. 
Philadelphia, 1929. 

423. Torreson, O. W., Murphy, T., and Graham, J. W., "Magnetic 
Polarization of Sedimentary Rocks and the Earth's Magnetic His- 
tory/' Journal of Geophyiscal Research, v. 54, No. 2 (June, 1949). 

424. Turekian, Karl K., "The Stratigraphic and Paleoecological Sig- 
nificance of the SR/CA Ratio in Sediments and Fossils." Petro- 
leum Geologist (March 28, 1955). 

425. Turner, F. J., and Verhoogen, Jean, Igneous and Metamorphic 
Petrology. New York, McGraw-Hill, 1951. 

426. Tuve, M. A., Annual Report, Director of the Department of 
Terrestrial Magnetism, Carnegie Institution of Washington, 1948- 

1949. Carnegie Institution Yearbook, No. 49. 

427. Tuve, M. A., Annual Report, Director of the Department of 
Terrestrial Magnetism, Carnegie Institution of Washington, 1949- 

1950. Carnegie Institution Yearbook, No. 50. 

428. Tuve, M. A., Annual Report, Director of the Department of 
Terrestrial Magnetism, Carnegie Institution of Washington, 1955- 
1956. Carnegie Institution Yearbook, No. 56. 

428a. Twenhofel, W. H., ed., "Environmental Significance of Dwarfed 
Faunas, A Symposium." Journal of Sedimentary Petrology, v. 18, 
No. 2 (Aug., 1948). 

4 28b. Twenhofel, W. H., Principles of Sedimentation. New York and 
London, McGraw-Hill, 1939. 

429. Umbgrove, J. H. F., "Recent Theories of Polar Displacement." 
American Journal of Science, v. 224, No. 2 (Feb., 1946). 

430. Umbgrove, J. H. F., The Pulse of the Earth, 2d ed. The Hague, 
Martinus Nijhoff, 1947. 

431. "U. S. Geological Survey Radiocarbon Dates I." H. E. Suess, 
Science, v. 120, No. 3117 (Sept. 24, 1954). 

432. "U. S. Geological Survey Radiocarbon Dates II." Rubin, Meyer, 
and Suess. Science, v. 121, No. 3145 (April 8, 1955). 

433. "U. S. Geological Survey Radiocarbon Dates III." Science, v. 123, 
No. 3194 (March 16, 1956). 

434. "University of Michigan Radiocarbon Dates I." H. R. Crane. 
Science, v. 124, No. 3224 (Oct. 12, 1956). 

436. "University of Pennsylvania Radiocarbon Dates I." Science, v. 
121, No. 3136 (Feb. 4, 1955). 

437. Urey, Harold C., "Measurement of Paleotemperatures and Tem- 
peratures, etc." Bulletin of the Geological Society of America, v. 
62, No. 4 (April, 1951). 



BIBLIOGRAPHY 419 

438. Urey, Harold C., The Planets, Their Origin and Development. 
New Haven, Yale, 1952. 

439. Urry, W. D., "Radioactivity of Ocean Sediments VI." American 
Journal of Science, 247:257-75. 

440. Urry, W. D., "The Radioelements in Non-Equilibrium Systems." 
American Journal of Science, 240:426-36. 

441. Victor, Paul Emile, Rapport prdliminaire. Expeditions polaires 
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442. Visher, S. S., "Tropical Cyclones and the Dispersal of Life from 
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4423. Volchok, H. L., and Kulp, J. L., "The Ionium Method of Age De- 
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(Pergamon Press, Ltd., London.) 

443- Wade, A., "The Geology of the Antarctic Continent." Proceedings 
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444. Wallace, Alfred Russel, The Malay Archipelago. New York, Har- 
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445. Wallace, Alfred Russel, Darwinism. London and New York, Mac- 
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446. Wallace, Alfred Russel, Island Life, 3d rev. ed. London, Mac- 
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447. Wanless, Harold R., and Weller, J. Marvin, "Correlation and Ex- 
tent of Pennsylvania Cyclotherms." Bulletin of the Geological 
Society of America, 43:1003-16 (1932). 

448. Washington, H. S., "Deccan Traps and Other Plateau Basalts." 
Bulletin of the Geological Society of America, 33:765 (1922). 

449. Webster, A. G., The Dynamics of Particles and of Rigid, Elastic 
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450. Wegener, Alfred, The Origins of Continents and Oceans. Trans- 
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Methuen, 1924. 

451. Weller, J. Marvin, "Cyclical Sedimentation of the Pennsylvania!! 
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No. 2 (Feb.-March, 1930). 

452. Westergaard, H. M., Theory of Elasticity and Plasticity. Cam- 
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453. Whitley, D. Gath, "The Ivory Islands of the Arctic Ocean." Jour- 
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454. Wilson, J. H., The Glacial History of Nantucket and Cape Cod. 
New York, Columbia University Press, 1906. 

455- Wilson, J. Tuzo, "On the Growth of Continents/' Papers and Pro- 
ceedings of the Royal Society of Tasmania. Hobart, Australia, 



42O EARTH'S SHIFTING CRUST 

456. Wilson, J. Tuzo, "The Origin of the Earth's Crust." Nature, v. 
179, No. 4553 (Feb. 2, 1957). 

457. van Woerkom, A. J., in Shapley, Climatic Change. 

458. Wool Industries Research Association, Leeds, England, personal 
communication. 

459. Wright, G. F., The Ice Age in North America, and Its Bearing 
upon the Antiquity of Man. New York, Appleton, 1889. 

460. Wright, G. F., Greenland Ice Fields and Life in the North At- 
lantic. New York, Appleton, 1896. 

461. Wright, W. B., The Quaternary Ice Age. London, Macmillan, 

1937- 

462. Wright, C. S., and Priestly, R. E., Glaciology. London, Harrison, 

1922. 

463. Wulff, E. V., An Introduction to Historical Plant Geography. 
Waltham, Mass., Chronica Botanica, 1943. 

464. "Yale Natural Radiocarbon Dates I." Blau, Deevey, and Gross. 
Science, v. 118, No. 3052 (July 3, 1953). 

465. "Yale Natural Radiocarbon Dates II." Preston, Person, and 
Deevey. Science, \. 122, No. 3177 (Nov. 18, 1955). 



INDEX OF NAMES 



Abrons, Stanley Howard, 8 

Akimoto, 308 

Alexander the Great, 52n. 

Almond, Mary, 33 

Anderson, W., 221-22 

Antevs, Ernst, 195, 211-13, 216, 224 

Anthony, Harold, 7 

Archer, William, 6 

Argyris, Thomas S., 230 

Arrhenius, Gustav, 303 

Bain, George W., 32, 37, 66, 71-73, 

177-78, 197 
Ball, Robert, 39 
Barghoorn, 61-63, 68, 315 
Barnes, Joseph, 240 
Barrell, 89, 156-57 
Bell, Robert, 233 
Belov, N. A., 235 
Benedict, F. G., 233 
Benfield, A. E., 117 
Benioff, H., 382 
Bergquist, N. O., 204 
Berry, 68-69 

Birdseye, Clarence, 240, 242 
Bishop, Mrs. Helen, 7 
Bishop, Sherman C., 260-64 
Blanchard, Jacques, 32, 309 
Bowen, 11 

Breen, Walter H., 7, 8, 385 
Brewster, E. T., 14041 
Brice, J. C., 8 
Bridgman, Percy L., 7, 21, 187, 

189, 191 > 35<>, 357' 358 
Brooks, C. E. P., 52, 59, 64, 68, 137, 

140, 224, 255, 309, 310 
Broterus, 248 
Brouwer, Dirk, 6, 17, 43 



Brown, Hugh Auchincloss, 6, 15- 

19, 170, 365-68, 373, 374, 381 
Bruckner, 281, 282 
Bucher, Walter H., 7, 84, 125, 227 
Buker, Errol, 6, 19, 343 
Bullard, E. C., 80 
Byrd, Richard Evelyn, 59, 168 

Campbell, James H., 6, 7, 13, 19 
21, 73, 90-105, 108, no, 111, 
114-15, 123, 159, 171, 197, 209, 

237 34o-7 8 379~ 8l 3 8 4 3 88 

Caster, K. E., 28 

Chaney, Ralph W., 27, 69 

Charlesworth, J. K., 35, 298 

Clegg, J. A., 33 

Clemence, G. M., 6, 368 

Clisby, Katharyn H., 290 

Cloos, Hans, 9, 10, 143-44 

Colbert, 62, 63, 66, 67, 68 

Coleman, A. P., 11, 34-38, 43, 67, 
68, 136, 170, 203-4, 219, 263, 
272, 278, 308, 311, 321, 366 

Columbus, Christopher, 52n. 

Commoner, Barry, 8 

Croll, James, 279, 280, 310, 311 

Cruzen, Rear Admiral, 166 

Dachille, Frank, 32, 193 

Daly, R. A., 9, 10, 21, 30, 35, 79, 

8l, 112, 117, 119, 132-33, 150, 
151-52, l6o, l6l62, 172-77, 

181-83, l86 > 187-89, 94> 221, 

357> 3 8l > 3 8 4 
Dana, J. B., 89 
Darwin, Charles, 225, 315, 316, 

325, 327-28, 335, 338 
Darwin, George H., 25, 32, 369 



422 



EARTH'S SHIFTING CRUST 



Davies, O., 39 

Day, A. L., 112, 114 

de Geer, Ebba Hult, 207, 211 

de Geer, Gerard, 46, 211 

Deininger, Mrs. Whittaker, 20 

DeRance, 64, 136 

de Vries, Hugo, 316 

Dickerson, 223 

Digby, Bassett, 239, 240 

Dillon, Lawrence, 195-96 

Dobrolet, Walter, 6 

Dobzhansky, Theodosius, 318 

Dodson, Edward O., 136, 271, 305, 

3 l8 > 3*9 33 6 
Dorf, Erling, 332 
Dorsey, H. G., 255 
Dougherty, Lyman H., 60 
Drayson, A. W., 43, 45 
Dufty, Mrs. Maely, 8 
du Toit, A. L., 37 
Dutton, Clarence, 83-84, 102 

Eardley, 115 

Eddington, A. E., 70, 197 
Einstein, Albert, i, 6-7, 8, 20, 55, 
114, 170-71, 172-74, 179, 185, 

186, 194-95* 345 35<>> 35 1 * 357* 

361-65, 382, 388, 390, 391 
Emiliani, Cesare, 43, 201, 202, 277, 

282, 294, 300, 309 
Eotvos, 357, 37 1-75 
Ericson, David B., 7, 55, 74, 270, 

293, 300 

Euler, Leonhard, 369 
Ewing, Maurice, 109, 141, 358 

Falconer, 233 

Feilden, 64, 136 

Finnegan, H. E., 222 

Firbaz, Franz, 207 

Fisk, H. N., 218-19 

Flint, Richard Foster, 54, 145, 201, 

211, 255, 272, 278, 287 
Forrest, H. Edward, 297, 299 



Frankland, John M., 7, 118, 190, 

35> 353' 359 
Frazer, James G., 389 

Geikie, Archibald, 189-90, 225, 

279 
Gidley, James William, 308 

Gilluly, 131, 221 

Gilman, Coburn, 8 

Godwin, Harold, 219 

Gold, T., 32, 197, 355 

Goldring, Winifred, 66 

Goldschmidt, Richard, 319, 320 

Grabau, Amadeus W., 125-26 

Graham, J. W., 32 

Grand, Mary Garrison, 7, 361 

Gregory, J. W., 136 

Gutenberg, Beno, 9, 11, 30, 32, 35, 
63, 79-80, 87, 88, 116, 118, 120- 
23, 137, 162-63, 189, 226, 354 

Hackett, Chauncey, 7 

Haldane, J. B. S., 318 

Hall, 89 

Halle, T. B., 223 

Hansen, L. Taylor, 30, 207 

Hapgood, Mrs. Norman, 8, 245 

Harris, Herbert, 240 

Hartnagel, C. A., 260-64 

Heiskanen, 182 

Henry, Thomas R., 9, 59, 60, 166- 

67 

Herz, F. F., 240, 248 
Hibben, Frank C., 7, 9, 207, 227, 

266-69, 271 

Hillaby, John, 218-19 
Hobbs, William H., 12, 104, 105, 

106, 113-14, 143, 358, 379 
Horberg, Leland, 47-48, 200, 202, 

379 

Hough, Jack, 50, 55, 202, 364 
Howard, John Langley, 8 
Howorth, H. H., 241-42 
Hoyt, Joel L., 258-59 



INDEX OF NAMES 



4*3 



Hubbert, M. King, 160 
Humphreys, W. J., 38, 69, 140, 

205-6, 252, 254, 285 
Hunt, J. C., 264 
Huntington, Ellsworth, 207 

Jacobs, Norman A., 8 
Jacobsen, Glen, 167 
Jaggar, Thomas A., 112-13, 152-53 
Jeffreys, Harold, 17, 27, 80, 117, 
i33> *63> 178, 181, 186, 188-89, 

35 1 * 359 3 6 9 
Joly, J., 87, 120 

Kalb, Bernhard, 167-68 

Kanwisher, John W., 208 

Karlstrom, Thor, 307 

Kay, Marshall, 7 

Kelly, Allan O., 32, 193 

Kenison, Frank, 6 

Kolbe, 299 

Kreichgauer, 392 

Kroeber, Alfred Louis, 40-41 

Krumbein, W. C., 9, 23, 89, 115, 

!3* 
Kulp, J. L., 55, 271 

Lambert, 30 

Lammers, William, 6 

Lapina, N. N., 235 

Lap worth, 105-6 

Lecomte du Noiiy, Pierre, 3i8f 

Libby, Willard F., 46 

Linehan, Daniel, 52n. 

Love, S. G., 258, 259 

Low, 203-4 

Lull, Richard Swann, 321, 331 

Lydekker, Richard, 238-39 

Lyell, Charles, 48, 234, 261, 304, 

3!3 
Lyman, Charles P., 232 

Ma, Ting Ying H., 32, 73-77, 19? 
McFarlan, E., 218-19 



Malaise, Rene*, 285, 299 
Mallery, Arlington H., 52n. 
Maxwell, James Clerk, 17, 25, 366- 

69 377 
Mayo, Charles, 7 

Mayor, A. G., 76 
Meinesz, see Vening Meinesz 
Melton, F. A., 160 
Mendes, J. C., 28 
Meryman, Harold T., 242-43 
Meyer, 195 
Millis, John, 271 
Moodie, Roy L., 261 
Munk, Walter, 33 

Nares, G. S., 64 

Negris, P., 142-43 

Neuville, H., 229-31 

Nikiforoff, C. C., 69 

Nolke, 138 

Nordenskjold, N. A. E., 234 

Nordenskjold, N. O. G., 52n., 168- 

69 
Olivier, Charles P., 1 1 

Pauly, Karl A., 32, 70-71, 195 
Penck, 196, 281, 282 
Perry, Ralph Barton, Jr., 7 
Peter the Great, 244 
Philipp, 107 
Piggett, C. S., 49 
Piri Reis, 520. 
Pirsson, Louis V., 80, 82 
Planck, Max, 365 
Poinsot, Louis, 377 
Politzer, Mrs. Use, 8, 391 
Pollock, James B., 223 
Priestly, Raymond E., 52, 60 
Punshon, E. R, 389 

Ramsay, Wilhelm, 161, 279 
Reid, Henry Fielding, 82 
Rensch, 336 



424 



EARTH S SHIFTING CRUST 



Revelle, Roger, 33 
Richter, C. F., 162-63 
Roberts, Leo, 7 
Routh, 369 
Rowe, Mrs. Stanley, 7 
Runcorn, S. K., 250 

Saks, N. V., 235 

Sanderson, Ivan T., 8, 230, 320 

Sarton, George, 7, 21, 392 

Sayles, R. W., 223 

Scholander, P. F., 208 

Schuchert, Charles, 80, 82, 140 

Schwarzschild, M., 390 

Scott, John, 7 

Scott, Robert Falcon, 166-67 

Scott, W. B., 64, 227-28 

Sears, Paul B., 290 

Seward, A. C., 63 

Shackleton, Ernest, 59 

Shaler, 219 

Shapley, Harlow, 6, 17, 35, 368-69 

Simpson, George Gaylord, 9, 315, 

329> 333~3 6 337 
Slichter, L. B,, u 
Sloss, L. L, 9, 23, 89, 115, 131 
Smart, W. M., 117 
Smith, Albert C., 138 
Smith, Warren D., 223-24 
Sonder, 106 
Stokes, William Lee, 39-40, 56- 

57> IS 1 
Stubbs, P. H. S., 33 

Stutzer, Otto, 311 
Suess, Eduard, 314 
Suess, H. E., 277, 300 
Sukachev, V. N., 246 
Sullivan, Eileen, 8 



Tatel, H. E., 150 
Tazieff, Haroun, 207 
Termier, Pierre, 140 
Thomas, Charles W., 171 
Toll, Baron, 234-35 
Tolmachev, I. P., 241-42, 256 
Tresca, M., 190 
Tuve, M. A, 150 
Tyndall, John, 39 

Umbgrove, J. H. F., 9, 28, 35, 60, 
68, 84-85, 106-8, 120, 125, 129, 
133, 138, 141, 142, 148, 156, 173, 

223, 332, 35 35 8 
Urey, Harold C., 11, 126, 202, 294 
Urry, W. D., 49-50, 52, 195, 202, 

300, 301, 364 

van Camp, Robert, 6 

Van Woerkom, A. J., 43 

Vening Meinesz, F. A., 28, 87-88, 

106-7, !73> *74> 39 2 
Verrill, Mrs, A. Hyatt, 7 
Volchok, H. L., 55, 271 
Vorse, Mrs. Mary Heaton, 7 

Wallace, Alfred Russel, 62-63, 65, 

220, 310, 325, 326 
Walters, M. L, 52n, 
Warrington, Henry, 5-6 
Wegener, Alfred von, 26-31, 133, 

136, 196, 386, 392 
Weller, J. Marvin, 312 
Willis, 138 

Wilson, J. Howard, 219 
Wollin, Goesta, 55 
Wright, G. F., 219 
Wright, W. B., 44, 52 



Tanner, W. F., 198 



Zeuner, 281, 282 



INDEX OF SUBJECTS 



Academy of Sciences (Russian), 8, 

244-45 
adaptation, 61, 228-32, 250, 322- 

23. See also mammoth 
adaptive radiation, 32Qff, 333ff 
Alaska, earlier location of pole, 

2?5 33~ 8 

amateurs, 3, 6 

ammonites, 63 

amphibians, 62, 63. And see in- 
dividual species 

ancient maps, showing ice-free 
Antarctica, 52n. 

"Angaraland," 137 

annual rings in fossilized woods, 
68-69 

anomalies, in Antarctica, 161, 163, 
172; in Arabian Sea, 174; in 
Cyprus, 173; in East Indies, 173; 
in Great Rift Valley of Africa, 
173; in Harz Mountains, 173; in 
Hawaiian Islands, 172, 174; in 
the Himalayas, 173, 176, 384; 
in India, 173-76; in Nero Deep, 
173; in Scandinavia, 161, 174; in 
U.S.A., 174; negative, 162, 173- 
75; positive, 175 

Antarctica, coal beds in, 59; ero- 
sion in, 59; evidence for dis- 
placement, 54, 364; forested, 60; 
icecap in, larger than Wisconsin 
icecap, 38 iff, and see icecap, 
displacement, centrifugal effect; 
possesses folded mountains, 59; 
summer described, i68ff; tem- 
perate periods in, 50-55, 58-61, 
217, 305; unglaciated, ibid.; see 
also Wisconsin glaciation, cores, 
ionium method, radioelement 



dating, Hudson Bay, displace- 
ment; tropical flora in, 60 

anomaly, as epeirogenic uplift, 
121-22; centrifugal effects of, 
179-80, 373-74; from triaxial 
deformation, 181-82. See also 
uncompensated mass, icecap, 
displacement 

antelope, 233 

anticlines, 88-90 

anticyclonic winds, 53, 215 

anti-Darwinians, 319 

"Appalachia," 141 

Archaeocyathidae, 59 

Arctic Ocean, only of Mesozoic 
age, 149 

armadillos, 335 

ash trees, 65 

asthenosphere, 14, 99-100, 185-92, 
353; currents in, alleged cause 
of mountain building, 87; fluid- 
ity, 186; liquid properties, basic 
assumption for displacement 
hypothesis, 388; not sharply 
demarcated from lithosphere, 
i5off, i85ff; solidity of, refuted, 
189; strength estimated from 
deep-focus earthquakes, 188-89; 
viscosity explains delay in iso- 
static adjustment, 179, 184; vis- 
cosity increased by pressure, 
i86ff. See also displacements, 
viscosity 

asymmetry of icecaps, i, i8ff, Fig. 



basalts, 133, 172; found on floor of 
Atlantic, 152. And see plateau 
basalts 



426 



EARTH'S SHIFTING CRUST 



beaches, on highlands, 224-25; on 
inland mountains, 142-43 

bears, 262, 335 

beaver, giant, 227, 262, 335; small, 
262 

"bipolar mirrorism," 327-29 

birch, 65 

bison, 233, 262; giant, 335 

"Brady Interval" (retreat of Wis- 
consin icecap), 201 

bursting stress on crust, 91, 92, 199, 
345> 35* 37 8 > 3 8 4J compared 
with crushing point of basalt, 
350; computed, 361; near criti- 
cal point now, 381 

calamites, 62 
Cambrian, 67 

camel, extinct in North America, 
2*27; in Pleistocene Alaska, 307- 

8, 335 336 

carbon dioxide gas, and Climatic 
Optimum, 209; causes general 
warming of climate, 208; and 
recession of icecap, 209; result- 
ing from volcanism, 207-8, 211 

Carboniferous, 62, 66, 68, 72 

caribou, 262 

"Gary Advance" (of Wisconsin ice- 
cap), 201, 211, 272 

centrifugal effect, i, 2, 158:, 374ff; 
calculated, 359-60; distinguished 
from Eotvos effect, 357; exist- 
ence questioned, 357, 365ff; this 
objection answered, 365-78; 
mechanism, Ch. XI passim; not 
exhausted in local crust defor- 
mations, 359; of anomalies, 172; 
of icecaps, 16-19, 1 59~^3, 172, 
igSff, 340, 356, 384; of triaxial 
deformation of earth, 184-85; 
still operative, 379-86; sufficient 
to fracture crust, 362 (and see 
fractures); tangential compo- 



nent, 341, Table III, 372. See 
also anomaly, displacement, 
Eotvos effect, icecap, isostasy, 
isostatic adjustment, uncom- 
pensated mass 

climate, Chs. II, III, VII, VIII, X; 
abrupt changes of, 15, 237-43; 
various explanations of these re- 
futed, 60-61; these changes evi- 
dence for displacement, 78; and 
only explanation for frozen 
mammoths, 244; gradual 
changes, 77-78; this theory re- 
futed, 78; measured by radio- 
element dating of pollen, 29off; 
in Siberia, 195, 234; unrelated to 
internal heat of earth, 118. See 
also cores, displacements, extinc- 
tions, ionium method, radioele- 
ment dating, volcanism 

"Climatic Optimum," 31, 54ff, 196, 
201, 209, 255 

climatic zones, evidence for dis- 
placements, 73; inconstant, 12, 
70, and Ch. Ill, passim; mineral 
components, 72$ 

coal beds, 59, 62, 64, 310-11; as 
evidence for displacements, 71; 
rate of formation, 31 off 

"Cochrane Advance" (of Wiscon- 
sin icecap), 201, 216; local and 
minor, 202 

coelacanth, 320 

conifers, 65 

"contemporaneity" of events with- 
in the same geological period, 
refuted, 38ff, 4 iff, 44, 45, 65-69, 
i28ff, 130, 131 

continental drift, 14, 26-31, 75-77, 
*33> l8 3 *96> 372; refuted, 27, 
28-30. See also Ma and Wegener 
in Index of Names 

continental shelf, 141, 142-44 

"continental slope," 141 



INDEX OF SUBJECTS 



427 



continents, ancient (Brooks the- 
ory), 137; building, related to 
volcanic islands and sedimenta- 
tion, 115; elevation and subsid- 
ence explained, 153-57 ( see a ^ so 
sea level, elevation, displace- 
ment); invaded by epicontinen- 
tal seas, 85, 140; this phenome- 
non quasi-periodic, 85; origin of, 
hitherto unexplained, 12, iggff; 
permanence alleged, 134-35, 
298; refuted, 135!!, 139-48, 150^, 
157, 298-300; shape correspond- 
ence, 28; strength of lithosphere 
at ocean bottoms, refuting 
"floating continents" idea, 28; 
submergence, as evidence for 
displacement of crust, 156-57; 
sunken, 137-45, 29gff, 326. See 
also land bridges 

cooling of earth, 82, no; adduced 
to explain isostatic anomalies, 
182; to explain mountain build- 
ing, 79-80; this theory refuted, 
87-88; to explain universal tem- 
perate climate, 66-67; tn * s t ^ ie " 
ory refuted, 67-69, and Chs. Ill, 
VII, IX passirrt 

coral, 62, 73^; evidence for dis- 
placement, 75-77 (see also Ma 
in Index of Names); seasonal 
variation in cells, 74; indicators 
of latitude, 73-74 

cores, 50-51, 54, 55-56, 271, 277, 
282, 284-87, 290-303, 305, 309. 
See also ionium method, radio- 
element dating 

crack in earth's crust, world-wide 
(Ewing canyons), 81, 109, no, 
113, 385; consistent with force 
pulling Americas southward, 
385; continuous earthquake ac- 
tivity along, 109, 385; related to 
displacement, past or impend- 



ing, no, 385; and volcanism, 

i*3 

craters, 126 

Cretaceous, 63, 68, 72, 75, 131, 309 

crinoids, camariate, 334 

crust, compression on, 100-2, 153, 
1 75-7 6 383-84; crushing 
strength (compressive strength), 
358; elasticity, 92, 101; folding, 
80-90; hydrostatic balance, 99- 
100; rapid warping, 216, 22226; 
resistance to fracture slight, 351; 
sinking under weight of sedi- 
ments, refuted, 81-82 (see geo- 
synclines); stretching, 9199, 
153; structure, i5off; tensile 
strength, 100, 124, 175-76, 186, 
200, 357-58, 391; thickness, 14, 
123-24; variation in thickness, 
124-25, 151-52. See also burst- 
ing stress, displacement, frac- 
tures, "mountain roots," nega- 
tive geography 

crustaceans, 73 

cycle of climatic change, 21,000 
years long, 309 

Dawn Redwood, 320 

deer, 262, 335 

"denudation," area of, 163 

"deposition," area of, 163 

deserts, in all geological periods, 
68; mainly in horse latitudes, 72 

Devonian, 62, 66, 68-69, 75> 7 

diastrophisms, diastrophic disturb- 
ances, 131, 312. See also dis- 
placements, mountain building 

diatoms, fresh- water, in mid- At- 
lantic, 299; evidence for land 
mass in that area, 299ff 

dinosaurs, 335; not degenerate, 
336; extinction attributed to 
displacements, 336 

displacements of crust, i, 2, 13-15, 
2off, 



428 



EARTH'S SHIFTING CRUST 



displacements of crust (Cont.) 

57, 176, 200, 203ff, 207ff, 

219, 237, 24gff, 287, 314, 390, 
and Chs. IX, XI, XII passim; 
approximate equality of extent, 
86; basic assumptions of hypoth- 
esis, 377, 387!!; cause local in- 
creases in crust strength, 176; 
discontinuous, 351-52; economic 
consequences of theory, 38off; 
effects, 95-96, Figs. II, V, VI, 
Ch. XII; evidence for, passim; 
topics cited in evidence, 387; 
evolution and, 322ff, Ch. X pas- 
sim; explain acceleration of geo- 
logical processes, 49, 309; and 
block mountains, no; and 
changes in sea level, 120-26, 196, 
311-12; and "Climatic Opti- 
mum/' 209-10; and climatic 
variation, 40, 65, 70, 78, 285, 
310, 312; and changes in oxygen 
content of atmosphere, 208; and 
conflict between Antevs and de 
Geer findings, 213; and differ- 
ences in extent of European vs. 
American glaciations, 213-15; 
and difficulties in isostasy the- 
ory, 178-79; and distribution of 
species, 329, 339; and emptying 
of ecological niches, 33 iff; and 
epeirogenic uplifts, 121; and 
extinctions, 251-56, 332, 334, 
336ff, 339; and fracture patterns, 
91-110; and gaps in fossil rec- 
ord, 338-39; and geographical 
isolation of species, 32224, 339; 
and geosynclines, 90; and growth 
of continents, 122, i53ff; and 
heat of earth, 116-19; and in- 
constancy of climatic zones, 70, 
303; and inconstancy of icecap 
locations, i7iff, 287; and "in- 
terstadials," 209-10; and land 



bridges, i38ff; and lateral com- 
pression of sedimentary rock in 
India, 176; and mountain 
ranges, i38ff; and rapid crustal 
warping, 216; and "sea mounts/' 
i47ff; and structure of crust, 
152-53; and tempo of evolu- 
tion, 322ff, 339; and various 
anomalies, 175-76; and Virenz, 
332ff, 339; and volcanism, 43, 
111-15, 196, 204-8, 269; and 
world-wide lowering of tempera- 
ture, 43; future, of Antarctic 
icecap, 380-86; impending ac- 
tivity, evidence for, 382!!; inter- 
vals between beginnings of, 
about 40,000 years, 277, 284, 
38off; intervals variable, 380; 
isostasy and, i59ff, 365-78; in 
North America, see Wisconsin 
glaciation and Ch. VII passim; 
northward in Siberia, 271 and 
Ch. VIII passim; Pennsylvanian 
cycles and, 313; periodicity, 85- 
86; perpetual, 304, 314; physical 
mechanism, Campbell hypoth- 
esis, 388, Ch. XI passim; objec- 
tions to this explanation, 22; 
answered, i97ff, 352-78; pos- 
sibly responsible for all funda- 
mental features of crust and 
earth's history, 314; prior to 
Wisconsin glaciation, Ch. IX 
passim; proposed causes, 15, 32, 
70; icecap as one of these, 17- 
21 and Ch. XI passim; rearward 
buildup of ice prolonging ac- 
tivity, 353-54, 3 8 5~ 86 ; su s- 
pended if both poles are in 
oceans, 354ff; this objection an- 
swered, 354-55; throughout 
Paleozoic, 313; time element, 97, 
128-31, 277, 284, 38off; viscosity 
of asthenosphere no great ob- 
stacle to, igoff. See also anomaly, 



INDEX OF SUBJECTS 



429 



Antarctica, asthenosphere, burst- 
ing stress, climate, earthquakes, 
extinctions, fractures, ice ages, 
icecaps, isostasy, isostatic adjust- 
ment, lowering of temperature, 
meridian of maximum thrust, 
mountain building and origins, 
poles, triaxial deformation, vis- 
cosity, volcanism 

distribution of species, i35ff, 325- 
29, 339; Ch. Ill, passim 

domes and basins, no; related to 
displacement, no, 120, 184 

downward projections of crust, 
124-25, 151-52, 190-92 

Drayson hypothesis, 43, and see 
Drayson in Index of Names 

Drosophila, 319 

earth, formed as a solid, n; cool- 
ing, 66-67 (and see cooling); 
heating, n, 11619 (and see 
heat); magnetic field, 33, 308; 
molten origin, discredited, 82- 
84, 112, 117, 182; triaxial de- 
formation of, 180-84. $ ee a ^ so 
centrifugal effect, crust, dis- 
placements, equatorial bulge, 
isostasy, poles 

earthquakes, 90103, 109, 113, 118, 
Figs. II-VI, Ch. XI; deep-focus, 
and strength of asthenosphere, 
188; function, 384; and impend- 
ing crust displacement, 382-86; 
in Assam, 383-84; in India, 383; 
pushed Himalayas up nearly 200 
feet farther from isostatic adjust- 
ment, 384; this phenomenon un- 
explainable save in terms of dis- 
placement, 384; major, from 
world-wide stress systems, 382; 
from icecap thrust, 382; increas- 
ing in frequency and violence, 
382-85; minor, of local origin, 
382; produce heat by friction, 



118; and triaxiality of earth, 
189. See also crack in earth's 
crust, displacements, fractures, 
geosynclines 

eccentricity of Antarctic icecap, 
i8ff, Fig. I, 198; contrasted with 
that of Wisconsin icecap, ig8ff 
elephants, 229-33, 33 6 > 337 
elevations of land, drastic changes 
in, 38, 142, 219-21; adduced to 
explain climatic change, 60-61; 
this theory refuted, 61; related 
to displacements, 120-23, 285. 
See also epeirogenic uplifts, 
mountain building, beaches, 
land bridges, displacements 
elk, American, 262; Irish, 262; 
killed and preserved by same 
sort of conditions as held for 
mammoth and mastodon, 262 
England, separated from Euro- 
pean continent within last 7,000 
years, 218-19 
Eocene, 64, 69, 309, 314 
Eotvos effect, 357, 371-75 
epeirogenic uplifts, i2off, 128, 153 
epicontinental seas, 85ff, 140, 148- 

49 

equatorial bulge, accounting for 
stretching and compression of 
crust, goff, 345-5 1, Figs. XIII, 
XIV, XV; lying beneath crust, 
346; origin, 370; and rotational 
stability, 17, 20, 25, 366. See also 
fractures, wedge effect 

equipotential surface, 370-72, 374, 
377; sea level, 372-73. See also 
geoid 

erosion, 48, 106, 152-53; and for- 
mer continents, 141; and iso- 
static adjustment, 162, 177; 
mountain building, 80-82; and 
peneplains, 177-78; and sedi- 
mentary rocks, 129 



43 



EARTH S SHIFTING CRUST 



Everest, Mount, increased height 
since 1950, and displacement, 

384 

evolution, 12, and Ch. X passim; 
causes, 3i5ff; and climate, 32off; 
and displacements, 322; "ex- 
plosive/' see Virenz; and glacial 
periods, 321; and macromuta- 
tions, 319; and mutation, 316- 
18; mystical explanations, 318 
19; "quantum," see Virenz; 
selection pressure, 318; unex- 
plained, 315; vast stretches of 
time required without drastic 
climatic change being adduced, 
3 i 6 20 

extinctions, 197, 207, 227; Ch. 
VIII passim; and impending dis- 
placement, 386; hitherto unex- 
plained, 228, 315. See also mam- 
moth, mastodons 

"Farmdale Advance" (of Wiscon- 
sin icecap), 200, 273, 307 

"Farmdale-Iowan Interstadial," 
200 

ferns, 62, 63 

floating of bodies from gases pro- 
duced in decomposition, 237; 
not observed in very cold waters, 

237 

foraminifera, and sea mounts, 148; 
and displacements, 287, 295-96; 
in Arctic, 287 

fossilization, a rare accident, 68; 
not limited to warm-climate 
creatures, 68 

fossil record, gaps in, 337-39; ex- 
plained, 129, 338 

foundering of continents, 1395 

foxes, 262 

fractures of the crust, 81, 91-99, 
log- 1 ^ 3 8 5 Figs. II-VI; and 
displacements, 91-99, 104-10, 
177, 204*1, 209, 364, 379, 391; 



major, 93, 935, 1135; minor, 93, 
115; more ancient systems oblit- 
erated by those from most recent 
displacements, 108; and moun- 
tain building, 91-99; older the- 
ories of origin refuted, 106-7; 
and wedge effect, 345ff, 351, 363. 
See also centrifugal effect, crust, 
displacements, equatorial bulge, 
magma, mountain building, 
mountains 

friction, subcrustal, 118; alleged 
brake on displacements, 353; 
this objection answered, 353 

frozen foods, 238-40; related to 
mammoth, 24off 

fusion of nuclei, 390 

genes, 316, 318, 319 
"geoid," 158, 179, 182, 183, 375, 
377; represented by sea level, 

373 

geosynclines, 87-90, 100, 115, 127; 
supposed origins, 89-90. See also 
centrifugal effect, displace- 
ments, mountain building 

glaciations, European, not con- 
temporaneous with North Amer- 
ican, 280-83, 292; Ch. IX passim 

glaciers, Ch. II passim, 67, 70, 193; 
not universally receding, 1 64-65, 
167-68. See icecap 

Glossopteris, 60 

"Gondwanaland," 137 

gradualism, 313-14 (see also Lyell 
in Index of Names); a habit of 
mind (Einstein quotation), 364 

gravitational contraction, insuffi- 
cient to account for earth's heat, 
116 

gravitational surface, 372-73, 377 

gravity, 37off; accounts for shape 
of earth, 158, 370. See also isos- 
tasy, isostatic adjustment 



INDEX OF SUBJECTS 



431 



Greenland, amphibians in, 62; 
centrifugal effect of icecap, 381; 
displacement in near future pos- 
sible, 38 iff; formerly unglaci- 
ated, 63, 64, 382, Chs. II, III, 
IX; ice sheet still growing, 164- 
65; in tandem with Antarctic 
icecap, 381; isostatic adjustment 
of, contradictory findings, 381; 
lignite in, 64; previous location 
of pole, 288-302 and Ch. IX 
passim; this discovery confirmed, 
292, 295, 308 

hazel, 65 

heat, subcrustal, 116-19; evidence 
for displacement of crust, 118; 
gradient differs in different con- 
tinents, 117; rate of dissipation, 
117-18 

"Heiskanen formula," 174 

Himalayas, uncompensated mass 
of, 173, 176; raised by Indian 
earthquake of 1950, 384; stand 
about 864 feet too high, 173 

horse, 227, 233, 262, 338; Pleisto- 
cene, 227, 335, 336 

horseshoe crabs, 320 

Hudson Bay, locale of pole during 
Wisconsin glaciation, Ch. VII 
passim, 272, 274-75, 288, 299, 
300, 303 

humidity, increased, and growth of 
icecaps, 165 

ice, accumulation far faster than 
isostatic adjustment, 162, 356; 
amount roughly constant, 217, 

357 

ice ages, alleged causes, 42; these 
in conflict with laws of physics, 
41-42; allegedly world- wide, 
$8ff, 328; this theory refuted, 
39-44; and "bipolar mirrorism," 
327-29; in Carboniferous, 67; in 



Pleistocene, 303, Ch. VII and 
IX; in pre-Cambrian, 67; in 
tropics, unexplained, 12, 34; 
specifications for adequate the- 
ory of, 56-57 

icebergs, not evidence of decline 
in Antarctic icecap, 170-71; 
mode of formation, 170 

icecap, Antarctic, accounts for 
otherwise unexplained Indian 
earthquakes, 383-84; and Cuzco 
earthquake, 384; and Ewing 
canyons, 385; and increased 
strain on crust, 384; alleged re- 
cession of, i64ff; eccentrically 
placed, i8ff, Fig. I; factor in 
world climate, 53; growth con- 
temporary with recession of Wis- 
consin glaciation, 53; isostatic 
adjustment of, i5gff; this asser- 
tion refuted, 163-64; less ancient 
than formerly believed, 50-56, 
161; rapid growth of, 164-65, 
171-72; uncompensated, i72ff. 
See also anomaly, centrifugal 
effect, "Climatic Optimum, 
crack in crust (Ewing canyons), 
displacements, ice ages, isostasy, 
isostatic adjustment, meridian of 
maximum thrust, poles 

icecap, North American, Ch. VII 
passim. See Wisconsin glaciation 

icecaps, i6ff, Chs. II, III, VII, VIII, 
IX, XI passim; alleged recession 
in Antarctica, i64ff;, best ex- 
plained by presence of land at a 
pole, 56-57; contrasted with 
Martian counterpart, 126-27; 
eccentricity, i8ff, i93ff; growth 
accelerated by world-wide warm 
climate, 165; in the Congo, 37; 
in Siberia, 25556; in tropics at 
sea level, 38; incredibly rapid 
disappearance, 202 (sec also 
carbon dioxide); "misplaced," 



43* 



EARTH'S SHIFTING CRUST 



icecaps (Cont.) 

35-37; mode of movement, 263; 
pressures exerted by, 35 iff, 358 
59; rapidity of growth, best evi- 
dence for centrifugal effect as- 
sumption, 200; rate calculation 
suggested by Einstein, 391; si- 
multaneous growth and disap- 
pearance, evidence for displace- 
ment of crust, 53; time element, 
277, 284; and world climate, 
Chs. II, III, VII. See also anom- 
aly, centrifugal effect, "Climatic 
Optimum," climate, displace- 
ments, earthquakes, ice ages, isos- 
tasy, isostatic adjustment, me- 
ridian of maximum thrust, poles 

ice sheets, compared with litho- 
sphere, 99; Cordilleran, 308; 
destroy evidence of previous 
glaciations, 278-79, 305; Euro- 
pean, entered Britain from 
northwest, 297-99; evidence for 
sunken continents, 142, 297-99; 
in India, 36ff; this glacier with- 
drew recently, 45ff; in Siberia, 
255-56; in tropics, 34ff, Ch. II 
passim; Keewatin, 272, 308; 
Labradorean, 272-73, 308; mean 
summer temperature the decid- 
ing factor in growth of, 195; 
melting, as evidence for dis- 
placement of crust, i7iff; not all 
receding, 164; Pleistocene, not 
yet compensated isostatically, 
162; rate of movement far slower 
in Antarctica than in Green- 
land, 170; still growing in 
Greenland, Baffinland, north- 
west U.S.A., 164-65. See also 
Greenland, isostasy, isostatic ad- 
justment, poles 

Ichthyosaurus, 63 



"Illinoisan" glaciation, evidence 
for pole in western Canada, 276 

Imperial Academy of Sciences 
(Russian), 8, 244-45 

impoverishment of island faunas 
and floras, explained, 326-27 

insolation curve, 307; insufficient 
to cause ice age, 43 

"International" and "Heiskanen" 
formulas for measuring isostatic 
adjustment, 174 

intrazonal adaptation, 33335 

ionium method, 41, 49-56, 271, 
282, 285, 293-94; confirmed, 55; 
pronounced reliable by Ein- 
stein, 364; sources of error in, 
55. See also cores, icecaps, radio- 
element dating 

"lowan Advance" (of Wisconsin 
icecap), 201 

iris, 65 

isolation, geographic, factor in 
evolution, 321, 324 

isostasy, 121, 134-35* i58ff; and 
centrifugal effect, 365-78; and 
conflicting measurements of 
gravity data, 381; departures 
from, 372ff; established only at 
long intervals, 178; theory ques- 
tioned, i6off, i72ff, 174, 175, 177, 
183, 382; theory stands or falls 
with displacement hypothesis, 
185; theory threatened by per- 
sistence of old anomalies and 
triaxial deformation, 182-83, 
188-89. $ ee anomaly, anomalies 
(locations), centrifugal effect, 
displacements, isostatic adjust- 
ment 

isostatic adjustment, 1590% 175, 
199, 216-17, 220-21, 251, 356-57, 
391; and centrifugal effects, 
375ff; and displacements, 178, 
198-99, 251, 255; contradictory 



INDEX OF SUBJECTS 



433 



measurements of in Greenland, 
381; "exists only in imagina- 
tion," 177; extreme slowness of, 
161-63; imperfect or lacking in 
Antarctica, 159, 160, 161; and 
in Scandinavia, 161; ineffective 
in counteracting centrifugal ef- 
fects of icecaps, 164; measure- 
ments highly doubtful, 160; a 
rare, exceptional condition, 178; 
seemingly lacking under pene- 
plains, 177 
ivory, 228, 238-39 

Jurassic, 63, 66, 72, 107, 131; coal 
deposits, 71 

Labyrinthodonts, 63 

land bridges, 135(1, 139, 285, 297- 
300, 305, 325-26; and evolution, 
321; explained, 149 

Laramide Revolution, 131 

lava floods, 111, 126, 204, 207 

Lepidodendron, 62 

Libocedrus, 65 

lignite, in Greenland, 64 

lime trees, 65 

lithosphere, 27-28, 99-100, 175, 
352. See also asthenosphere, 
crust, displacements, earth- 
quakes, fractures 

"living fossils/' 320-21 

lowering of temperature, world- 
wide, and volcanism, 42-43, 206; 
explained by displacement, 43; 
will not explain simultaneous 
glaciation and deglaciation, 194; 
will not explain Wisconsin gla- 
ciation, 194-95; wrongly as- 
sumed, 38-44 

macromutation, 319 
magma, 84, 153, 157, 188; and 
fractures of crust, 91, 96, Figs. 



III-VI, 119-120, 122-123; and 
mountain building, 98-100 

magnetic field of earth, changes 
in, related to displacements, 33, 
308 

mammoth, 227, 228, 250-51, 256, 
258, 261, 335; Beresovka, 8, 244- 
49, 250, 253ff; diet included 
grasses and buttercups, 243, 246- 
47, but no conifers, 248, nor 
typical Arctic plants, 246-47; 
probable cause of his death, 
253-55; stomach contents ana- 
lyzed, 245-49; species, edibility, 
239-40; frozen, 228, 240-44; in 
summer, 243; lacks sebaceous 
glands, 229; not adapted to cold, 
228-32; probably same species 
as Indian elephant, 233; re- 
mains allegedly washed to polar 
islands by spring floods, 234; 
refuted, 235-36; source of ivory, 
228; study of skin, compared 
with that of Indian elephant, 
229; subcutaneous fat layer, 
231-33; tusks dredged up from 
Arctic Ocean, 251 

"Mankato Advance" (of Wiscon- 
sin icecap), 201, 211, 288 

"Mankato Maximum" (high point 
of Mankato Advance phase of 
Wisconsin icecap), 201, 202, 212, 
213 

maps, confirming hypothesis of ice- 
free period in Antarctica, 52n. 

Mars, 126-27 

mastodon, 227, 257-65, 335; diet 
included plants common in 
present-day New York State, 
260, 264-65; survived ice age, 
266; found in bogs and swamps, 
257-58; stomach contents ana- 
lyzed, 257, 264 

mathematics, limitation of, 378 



434 



EARTH'S SHIFTING CRUST 



"maturity" of a species. See intra- 
zonal adaptation 

meridian of maximum thrust 
(presently 96 E. Long.), 15, 
ign. and Fig. I, 66, 92, 95, 96, 
109, 128, 220-21, 356, 383 

meridional faults, same as major 
fractures. See fractures 

meteoric phenomena, explainable 
only in terms of planetesimal 
hypothesis, 11 

meteorological factors of glacia- 
tion, 38 

Miocene, 65, 235, 314 

"missing links," 337-39 

moon, mountains on, formed by 
collisions, 126; allegedly torn 
away from Pacific basin, 183 

moose, 262 

moraines, 70; evidence for dis- 
placement of crust, 70, 288 

mountain building and origins, 
Campbell hypothesis, 90-103; 
chronology examined, 128-31; 
explainable by displacements, 
85-86, 90; from cracking and 
buckling of crust, 80-81; miscel- 
laneous explanations, 87; not 
exclusively from erosion, 81; not 
from cooling of earth, 79-80; 
not from shrinking of crust, 83- 
84; not simultaneous and world- 
wide, 130; on ocean bottoms, 
149; related to volcanism, 80, 
111-15; source a world-wide 
force, 83-84; this force quasi- 
periodic, 84-85; nearly contin- 
uous, 131; source of energy, 
103-4; unexpectedly frequent, 
i28ff; unexplained, 79ff, 176. See 
also centrifugal effect, crust, dis- 
placements, fractures, geosyn- 
clines, "sea mounts," volcanism 

"mountain roots," 124, 192 



mountains, 12, 15, Ch. IV; absent 
on Mars, 126-27; aid in distri- 
bution of species, 327-29; and 
centrifugal effect, 103-4; an< ^ geo- 
synclinal theory, 89-91; and 
magmatic intrusions, 98-100; 
different kinds described, 80; in 
Antarctica, 59; island chains of, 
80, 115-16; source of energy for 
folding, 103-4; submerged, 80, 
116; volcanic, 80. See also crust, 
centrifugal effect, geosynclines, 
magma, moon, Paricutin, "sea 
mounts," volcanism 

mutations, 3i6ff; incapable of pro- 
ducing new species, 316-17; ma- 
jority harmful or indifferent, 
317; and natural selection, 317; 

"systematic," 3igff; this theory 
adduced to solve problem of 
time, 320; discredited, 319 

natural selection, 315 (see evolu- 
tion); incapable of producing 
new species, 316; requires exces- 
sively long time, 318 

"Nearctis," 137 

nebular theory of earth's origin, 
10; discredited, 11-12 

"negative geography," 124 

neo-Darwinians, 316-19 

New Siberian Islands, site of mam- 
moth remains, 234, of fruit trees, 
234-36; forested in Miocene and 
Pliocene, 235 

niche, life, sgoff; ecological, ibid.; 
emptying explained, 331 

"North Atlantis," 137, 140 

oak, 65 

oblateness, and poleward com- 
ponent of gravity, 375. See equa- 
torial bulge 



INDEX OF SUBJECTS 



435 



ocean basins, origin unexplained, 
12, i45ff; alleged permanence, 
1506:. See also beaches, conti- 
nents (sunken), foundering, os- 
cillation of ocean bottoms, sea 
bottoms, "sea mounts" 

Ohio glaciation, 48, 273; evidence 
for displacement, 379-80 

Old Red Sandstone formation, a 
fossil desert, 68 

Oligocene, 107 

Ordovician, 75 

orogenic uplifts, 120 

oscillation, rhythmic, of ocean bot- 
toms, 142, 148 

oscillation of ice sheets, 48, 57, 165, 
204ff. See also volcanic dust, 
volcanism 

Oxygen- 18 method, 294 

Paleocene, 64 

palm trees, 320 

parallelogram of forces, used in 
computing centrifugal effect and 
its tangential component, 343- 

44 
Paricutin, 80; related to present 

beginning of displacement, 384 
peat bogs, 64 
peccaries, 262, 335 
peneplains, and isostatic adjust- 

ment, 



"Pennsylvanian" period (Carbon- 
iferous), 312 

periodicity, of displacements, 85- 
86, 277, 284, 38off; of mountain 
building, 84-86; accounted for 
by displacements, 85-86 

permafrost, 223, 241, 244, 256 

Permian, 63, 72, 30 

Permo-Carboniferous, 68, 71, 311; 
coal deposits, 71 

Peter the Great, 244 

pines, 65 



Piri Reis maps, confirming recent 
deglaciation of Antarctica, 52n. 

pivot points in a displacement, 15. 
See also triaxial deformation of 
earth 

plane trees, 65 

planetesimal hypothesis, 11 

planetoids, collision with earth a 
possible cause of displacements 
of crust, 32 

plasticity, of solids under pressure, 
190-91 

plateau basalts, 119, 153, 188 

Pleistocene, 70, 107, 131, 196, 208, 
218, 227, 235, 267-68, 277, 309, 
335; accepted chronology of gla- 
ciations weak, 278-83; ended 
catastrophically, 267-69; Euro- 
pean glaciations not contempo- 
rary with American, *8off; fifth 
glaciation identified, 278, 282; 
ice sheets not fully compensated 
to date, 162 

plication, 83, 89 

Pliocene, 69, 235, 314 

"pluvial" periods, 39 

poles, alleged immobility of, as 
example of hardening of the 
categories, 25, 31, 61, 386; as 
example of circular reasoning, 
65-66; and gyroscopic effect of 
earth's rotation, 24 (see also 
equatorial bulge); causes of ap- 
parent shift, 24ff (and see dis- 
placements); in Alaska, Ch. IX; 
in Greenland, Ch. IX passim; 
that location accounting for 
New York temperate-zone fauna 
enclosed in ice sheet, 289; 
method for locating earlier posi- 
tions, 274ff; position of, 13; posi- 
tion after next displacement, 
386; shifts a necessary hypoth- 
esis, 3off, 386-87; stability of, 



436 



EARTHS SHIFTING CRUST 



poles (Cont.) 

Ch. I, 365; wanderings, 32-33. 
See also Hudson Bay, icecaps, 
Wisconsin glaciation 

pollen, agoff 

poplar, 65 

Pre-Cambrian, 67 

precession, 43, and see Drayson in 
Index of Names; allegedly re- 
lated to 2i,ooo-year climatic 
cycle, 310 

"predictability," 37Qff; and future 
developments, Ch. XII passim; 
vindication of displacement hy- 
pothesis, 379-80 

public interest, necessary for scien- 
tific advancement, 3 

quick-freezing processes, 238-44 

radioactivity, subcrustal, 87, 116; 
alleged cause of mountain build- 
ing, 87; proposed source of in- 
ternal heat of crust, 116-17 

radioelement dating, 29, 41, 44-56, 
130, 195, 202, 21 off, 307, 309, 
374; called reliable by Einstein, 
364; questioned because of revo- 
lutionary conclusions, 47-48, 
212-13, 29off. See also cores, 
ionium method; Hough and 
Urry in Index of Names 

radiolaria, 171; as evidence for in- 
creasing coldness of Antarctic 
waters, 171 

reptiles, along Dvina River, 63; 
in Antarctica, 60; in various sub- 
Arctic regions, 63 

rhinoceros, woolly, 227, 233, 234 

Rift Valley (Africa), 81, 143-45, 

'73 
rifts and rift valleys, 81, 109, no, 

113* 385 

"Riss" glaciation, evidence for 
Eurasian pole, 275 



rotational stability, 17, 20, 25, 366- 

69 

sabertooth cat, 227, 233, 234, 335, 

336 

San Augustin Plains, 29off 

Sangamon Interglacial, 276, 292, 
304; contemporary with Wurm 
glaciation, 292 

scorpions, 320 

sea bottoms, contain mountain 
ranges, 29, 145!!; contain vol- 
canoes, 29; cores taken from, 
see cores, ionium method, radio- 
element dating; evidence for 
sunken continents, 137-45, 2995, 
326 (see also land bridges); not 
deeply sedimented, 29, 146, 148- 
49; not smooth plains, 28-29, 
145; recurring uplifts, 142, 148. 
See also continents, crust, moun- 
tain building, volcanic islands, 
volcanism 

sea level, as equipotential surface, 
371, 373; changes in, 15, 120-26, 
134, 196, 216; changes unex- 
plained by melting of icecaps, 
196, 2i7ff, 220; "eustatic" 
change, 272; evidence for fall, 
223; fall explained by growing 
Antarctic icecap, 221-23, 226; 
not universally rising, 222 

"sea mounts," i47ff 

seasonal changes, 68-69 

sedimentary beds of continents, 
formed under sea, 140 

sedimentary rocks, 59, 78, 129, 310; 
95% ground down, 129 

sediments, marine, 7 iff, 197, 271, 
Ch. XI; extremely slow deposi* 
tion rate, 146; and turbidity, 
146-47. See also cores, ionium 
method, radioelement dating, 
sedimentary rocks 



INDEX OF SUBJECTS 



437 



selection pressure, mild, 318; 
strong (i.e., major climatic 
change), 321 

Sequoia, 65 

sharks, 320 

shrinking of crust, 82-84, 87, no; 
refuted, 83-84. See also cooling 

"sial" and "sima," 152 

Sierra Nevadas, accounted for by 
"gridiron" fracture systems, io6 

Silurian, 75, 129 

simplicity of a theory, 388 

sloth, giant, 227 

snow, increased fall in Antarctica, 
164-65; rapid accumulation in 
Antarctica, i67ff; explained, 169 

solids, behavior of, at extremely 
high pressures, 189; relationship 
to deep-focus earthquakes, 189 

species, adaptation to different cli- 
mates, 61, 322-23; "degenera- 
tion" concept refuted, 334-37; 
drastic climatic change and, 
322-24; extinctions, 197, 207, 
227; history compared with in- 
dividual growth and aging, 
333-37> this notion likened to 
medieval scholastic logic, 333; 
"maturity," see intrazonal adap- 
tation; mutations and, 316-18; 
new, not produced, 3i6f; tropi- 
cal, survival refutes theory of 
simultaneous world-wide glacia- 
tions, 328; "youth," see adap- 
tive radiation. See also adapta- 
tion, climate, distribution, 
extinction, ice ages, land 
bridges, mammoth, mastodon, 
volcanism 

sphenodon, 320 

Spitzbergen, formerly warm, 62-65 

stabilizing effect of equatorial 

bulge, 17, 20, 25 
v storms, 236, 254-55, 266-71 



strandlines, 224ff 

stratigraphy handicapped by ero- 
sion, 129 

subcrustal currents, 87-88; lack of 
evidence for, 88 

sunspot cycles, 165 

surface of mass, 372-73, 377 

swamp-cypress, 65 

"Swedish Time Scale," 211. See 
varves 

"sweepstakes" process in distribu- 
tion of species, 326 

synclines, 90* See also geosynclines 

Taxodium, 65 

"Tazewell Advance" (of Wiscon- 
sin icecap), 200-1, 218 

"Tazewell Maximum," 211 

Teleosaurus, 63 

tempo, of evolution, Ch. X; of 
geological change, 12. See also 
displacements, icecaps, moun- 
tain building 

"Tethys Sea," 137, 140 

thermal energy arriving at surface, 
66 

tigers, 230; their thick fur not an 
adaptation to cold, 232 

tree ferns, in Antarctica, 60 

Triassic, 63, 130; coal deposits, 71 

triaxial deformation of earth, 180- 
84; amount of equatorial oval- 
ness, 181; evidence for displace- 
ment, 183-84; irreconcilable 
with isostasy theory, 183 

trilobites, 67 

"Two Creeks Interstadial," 201 

Tyrannosaurus rex, 320 

uncompensated mass, 341, 373-77. 
See also anomaly 

uniformitarianism, 48, 304, and see 
Lyell in Index of Names 

universal temperate climates, re- 
futed, 65-70 



438 



EARTH'S SHIFTING CRUST 



varves, 68, 211, 309; imply seasonal 
changes, 68 

Viking settlements, 164; over- 
whelmed by growing ice sheets, 
165 

Virenz, Virenzperiod, 329-31; 
coincide with periods of drastic 
geological change, 33 iff; follow 
creation of empty niches by ex- 
tinctions, 337 

viscosity of asthenosphere, 14, 86, 
179, 184, i86ff; decreased by 
heat, 187; increased by pressure, 
i86ff. See also asthenosphere, 
displacements 

"vital force" in species, a piece of 
scholastic logic, 333; discredited, 

334~37 

volcanic dust, relationship to cli- 
mate, 2O5ff, 211 

volcanic glass shards, found in At- 
lantic cores, 294, 296 

volcanic islands, location ex- 
plained, 115 

volcanic zones, distribution unex- 
plained, 111-12; related to frac- 
ture systems, 113-14 

volcanism, 12, 42-43, 97, 304, 312; 
and carbon dioxide gas, 207-8; 
and Ewing canyons, 113; and 
extinctions, 207, 268-70, 304-5; 
and fracture systems, 113; and 
immense increase of precipita- 
tion, 253, 264; and impending 
displacement, 386; and moun- 
tains, 80, 111-15; an d storms, 
268-71; and toxic gases, 269; 
and Wisconsin glaciation, 196, 
200, 204-10; and world-wide 
lowering of temperature, 205- 
6, 252, 270; cause of readvance 
of icecap, 205-6, 252; not merely 
local phenomenon, 112-13; the- 



ories of origin, 112-14; unre- 
lated to alleged molten origin 
of earth, 112. See also climate, 
crack in earth's crust, displace- 
ments, extinctions, magma, Pari- 
cutfn 

walnut, 65 

warm-climate life in polar zones, 
f2, 25, 58-65, and Ch. Ill pas- 
sim 

warming of climate, world-wide, 
refuted, 164-65. See also climate 
and Chs. II, HI passim 

water, volume approximately con- 
stant over geological time, 156- 
57; as evidence for crust dis- 
placement, 156-57 

water lilies, in Greenland, 65; in 
Grinnell Land, 64, 65; in Spitz- 
bergen, 64 

wedge effect, 345-51; and equato- 
rial bulge, Figs. XIV, XV, 348ff, 
36off; and fractures, 345; multi- 
plies centrifugal thrust by 500, 

349 

whale, 337 

Wisconsin glaciation, 45, 48, 54, 
Ch. VII, 257, 266, 268, 277, 278, 
283ff, 287ff, 289, 302, 307, 309, 
352, 379 3 8 2; oscillations of, 48, 
ig6ff, 281. See also volcanism 

wobble, in earth's rotation, 16-17, 
32. See also Blanchard and 
Gold in Index of Names 

wolves, 245, 335 

wool, 229-30 

world-wide system of submarine 
rifts, 81, 109, no, 113, 385 

"youth" of a species. See adaptive 
radiation 

zones. See climatic zones