1. DO THE POLES MOVE?

2. THE GEOMAGNETIC EVIDENCE

3. BRIEF SURVEY OF THE EARTH’S STRUCTURE

4. CONTINENTAL DRIFT: THE THEORY OF ALFRED WEGENER

5. CONTINENTAL DRIFT: THE NEW THEORY

6. THE HYPOTHESIS ACCORDING TO DIETZ

7. SEA-FLOOR SPREADING

8. HEEZEN’S DIFFICULTIES

9. HIS SOLUTION

10. FURTHER OBJECTIONS TO SEA-FLOOR SPREADING

11. A POSSIBLE SOLUTION: POLAR SHIFT

12. THE SPEED OF POLAR SHIFT

13. THE MECHANISM FOR POLAR SHIFT

14. IS THE POLE MOVING NOW?

1. THE FAILURE OF THE OLDER THEORIES

2. THE MISPLACED ICE CAPS

3. WORLDWIDE PHASES OF COLD WEATHER

4. THE NEW EVIDENCE OF RADIOCARBON DATING

5. CONCLUSION

1. AGES OF BLOOM IN ANTARCTICA

2. WARM AGES IN THE NORTH

3. UNIVERSAL TEMPERATE CLIMATES—A FALLACY

4. THE EDDINGTON-PAULY SUGGESTION

5. THE CONTRIBUTION OF GEORGE W. BAIN

6. THE CONTRIBUTION OF T. Y. H. MA

7. ON THE RATE OF CLIMATIC CHANGE

1. REMARKABLE FEATURES OF THE LAST NORTH AMERICAN ICE CAP

2. THE WARM ARCTIC OF THE ICE AGE

3. SOVIET EVIDENCE OF THE WARM ARCTIC

4. EVIDENCE FROM JAPAN

5. EVIDENCE FROM THE COAST OF MEXICO

6. EVIDENCE FROM AFRICA

7. EVIDENCE FROM TASMANIA

8. CONFIRMATION FROM ANTARCTICA

9. THE EVIDENCE OF AN ANCIENT MAP

10. CONFIRMATION FROM SOUTH AMERICA

11. THE RELATIONSHIP OF THE WISCONSIN ICE CAP WITH THE GLACIATIONS IN EUROPE ...

1. THE ACCELERATION OF EROSION AND ITS CAUSE

2. THE CAUSE OF OSCILLATIONS OF THE ICE SHEET AND THE CAUSE OF THE CLIMATIC ...

1. THE TEMPO OF DEGLACIATION

2. THE LAST MAJOR ADVANCE OF THE ICE SHEET

3. THE RETREAT OF THE ICE

Part I. THE RADIOCARBON EVIDENCE

Part II. THE EVIDENCE FROM DEEP-SEA CORES

Part I. - MOUNTAINS AND GREAT RIFTS

Part II. VOLCANISM AND OTHER QUESTIONS

1. THE EXTINCTION OF THE MAMMOTHS

2. THE MAMMOTH’S ADAPTATION TO COLD

3. THE PRESENT CLIMATE OF SIBERIA

4. A SUDDEN CHANGE OF CLIMATE?

5. THE BERESOVKA MAMMOTH

6. THE INTERPRETATION OF THE REPORT

7. STORM!

1. THE LOST SEA OF THE ANDES

2. THE PLEISTOCENE GRAVEYARDS OF SOUTH AMERICA

3. “FRESHNESS” OF FOSSIL REMAINS

4. THEORIES AND CONSIDERATIONS

1. THE CAUSE OF EVOLUTION

2. THE PROBLEM OF TIME

3. CLIMATE AND EVOLUTION

4. THE DISTRIBUTION OF SPECIES

5. THE PERIODS OF REVOLUTIONARY CHANGES IN LIFE FORMS

6. THE EXTINCTION OF SPECIES

7. THE GAPS IN THE FOSSIL RECORD

8. SUMMARY

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The Path of the Pole
The Mystery of Acambaro
Vimana Aircraft of Ancient India & Atlantis
The Return of the Serpents of Wisdom
Lost Continents and the Hollow Earth
Atlantis In America: Navigators of Ancient World

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TO THE SPIRIT OF FREDERICK S. HAMMETT

Late Director, Cancer Research Center
of the Lankenau Hospital of Philadelphia.

A Pioneer in Science, a Champion of the Free Mind;

An Artist in Intellectual Inquiry;
A Fighter Against Those Blights of the
Scientific Community: Smugness, Intolerance
and Materialism.

LIKE many people, I was introduced to Earth’s Shifting Crust not by reading the original text nor through discussion in the technical journals, but through reading an abridged version in The Saturday Evening Post. This was an unusual experience, to read something of scientific interest in a family magazine, but what I read was even more unusual. I found myself reading a reasonably plausible explanation—the first ever printed—of the major deformations that have racked the earth’s crust. The abbreviated version so intrigued me that I acquired a copy of the complete work at the earliest opportunity. The full text proved to be even more stimulating than its abbreviated predecessor. That first edition of the book was introduced to the public, through its foreword, by the eminent scientist Albert Einstein. I must confess that this fact impressed me to a considerable degree. At the time it never occurred to me that I might be asked to present the second edition; in fact, this still strikes me as somewhat incongruous.

Perhaps at this point I should briefly introduce myself to the reader. I am a mining geologist and a passable mineralogist, engaged in recent years in teaching these subjects. Geology, like all branches of science, has become separated into a maze of specializations. The adherents of one specialization are certainly more than dimly aware of what is going on in other fields, but can hardly consider themselves expert in any but their chosen field. I should not care to be accused of implying, through failure to admit the contrary, that I am a competent critic of Hapgood and Campbell’s work. I most emphatically am not.

After carefully reading Earth’s Shifting Crust, I began searching through the technical journals and other likely sources for the discerning criticism that I felt should be forthcoming from experts in the field. I should have known better than to expect it, I suppose, but hope springs eternal. A reaction came, of course, and largely it came from men who under ordinary circumstances are both rational and competent, but their reaction could hardly be described as rational; hysterical would be a better description. One observed, indignantly, that Hapgood was not a geologist. Admittedly this is a cardinal sin but hardly one punishable by scientific excommunication. Another cited, but failed to name, a scientist whose findings conflict with those of several world-renowned authorities selected by Hapgood as sources of technical data, and used this lack of agreement as an incontrovertible condemnation of the entire book.

I could continue with numerous examples, but this would be pointless. The fact is that almost without exception Americans commenting on the book couched their discussion in thick and unwarranted sarcasm, selecting trivia and factors not subject to verification as the bases for condemnation, seeking in this way to avoid the basic issues. Only the European reviewers were gracious enough to be fair, not that they accepted the theory without question, but they were prepared to offer it its day in court. Nowhere, in all that has been written about the book, have I found a single authority who has calmly and rationally offered a clear and documented criticism of the basic theory involved: that uncompensated masses on or in the earth may cause the earth’s crust to slip over its core. Frankly, I wish someone would.

In the years since publication of the first edition of this work we have had, among other things, the benefit of the research of the International Geophysical Year. Incorporation of these and other data has had two extremely important effects upon Hapgood’s theory: first to force a revision of the theory in relation to the mechanism of crustal displacement, and secondly to add tremendously to the weight of evidence supporting the thesis that crustal displacement has occurred. Regarding the first of these I believe that the author is to be congratulated for having the flexibility to adapt to new facts as they have become available. For the second, whereas there may have been a time when the occurrence of dislocations of the crust with respect to the earth’s rotational poles could have been questioned, I personally feel that in the light of the data presented by Hapgood in this, the second edition of his book, such dislocations are no longer a matter of question.

Like many another engaged in teaching, I have grown weary of apologizing to my students for teaching time-worn theories whose logic, to use a kind word, is indefensible. The plain fact is that the logic of all previous theories of the earth’s deformation is so obviously contrived, the holes are so gaping, that one is inclined to suspect that danger lurks there for the unwary. Now at last in Hapgood and Campbell’s theory, actually a coalition of several older and poorly enunciated ideas, we find the first outwardly reasonable explanation of the observed facts in several major geological fields. Now I ask-no, I implore—my colleagues, those most competent to assume the task, to attack this theory with the weapons of well-documented proof. Or, failing this, let them build upon it to a better, clearer understanding of the forces that have deformed this planet we live upon. Let us not bury this idea prematurely through prejudice, as so many valuable ideas of the past have been buried, only to be sheepishly exhumed in later years. If it is an unworthy thing let it be properly destroyed; if not, let it receive the nourishment that it deserves.

THE most significant change in this book since Albert Einstein wrote his Foreword for the American edition and Professor Kirtley Mather wrote one for the British, Spanish, and Italian editions is directly related to the question on which they both expressed their strongest doubts: the ice-cap “mechanism” by which I proposed to account for displacements of the earth’s outer shell. Their doubts have been vindicated by the progress of earth studies in the past decade. Advancing knowledge of conditions of the earth’s crust now suggests that the forces responsible for shifts of the crust lie at some depth within the earth rather than on its surface.

Despite this change in the character of the proposed explanation of the movements, the evidence for the shifts themselves has been multiplied many fold in the past decade. The main themes of the book—the occurrence of the crust displacements even very recently in geological history, and their effects in forming the features of the earth’s surface—therefore remain unchanged.

THE AUTHOR

BRITISH, SPANISH, AND ITALIAN VERSIONS

by Kirtley F. Mather
Professor of Geology, Emeritus,
Harvard University; former
president, The American Association
for the Advancement of Science

THE idea that the history of the earth involves the shifting of its thin “crust” from time to time and place to place is certain to receive increased attention in the next few years. Knowledge is rapidly accumulating concerning the spatial relations of the crust and the underlying “mantle.” Information regarding the physical properties of these parts of the stratiform planet is being secured by geophysicists. Many specific facts are now available concerning local changes of level and of geographic position of points on the earth’s surface. The geologic records of the past are replete with items that suggest significant differences between the latitude and longitude of many places in earlier epochs and those of the present time.

The need is clearly apparent for a synthesis of all these many data that would integrate them in a broadly inclusive scheme and give them unified meaning in relation to a general principle. In geology, indeed in all scientific disciplines, analysis must lead to synthesis which in turn must be followed by further analytical studies in the repetitive cycles of advancing knowledge and understanding. This is evidently the aim of this thought-provoking book. Its greatest value will be found in the stimulus it should give to discussion, debate and controversial argument.

The concept of crustal shifting as an important and frequently repeated episode in earth history is not new. But the marshaling of data from many diverse fields of study and their interpretation in causal terms are sufficiently novel to make the authors’ ideas worthy of careful study and appraisal. Indeed, certain aspects of their application of the general concept are radically new and will undoubtedly lead to healthy controversy. I cannot, for example, accept as valid certain interpretations made by the authors of some of the facts they cite, but these are minor matters and do not necessarily invalidate their major argument. My own confidence in the principle of isostasy leads me moreover to discount the computation of tangential forces resulting from “off-center” ice caps, but this is certainly a matter for further study. The results of geophysical research must accord with the facts of earth history if they are to be accepted as completely trustworthy.

All of which means that the authors of this novel interpretation of crustal movements have made a distinctive contribution to geological lore which should be of interest to all geologists. The numerous unsolved problems to which Mr. Hapgood directs attention should be the subjects of intensified debate among scientists in every part of the world. It should moreover be noted that this book is written in clear, nontechnical language. Mr. Hapgood has succeeded in bringing the thought within the reach of every educated layman. It is a readable survey of geological problems that too long have been the province of specialists alone.

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 itself—of 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 climatic 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 consequence 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 presentation of this idea. He has also set forth, cautiously and comprehensively, 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 displaced 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 centrifugal momentum, which would tend to displace the crust by centrifugal effect. I think that this deduction might be capable of verification, at least approximately. This centrifugal momentum should in any case be smaller than that produced by the masses of deposited ice.

UNTIL a decade ago the idea that the poles had often changed their positions on the earth’s surface was regarded as extreme, improbable, and unsound. It was advocated strictly by cranks. Nobody who was anybody in the scientific world would have anything to do with it.

Fashions change. Today every other book dealing with the earth sciences devotes space to polar wandering and continental drift.

Polar wandering is based on the idea that the outer shell of the earth shifts about from time to time, moving some continents toward and others away from the poles, changing their climates. Continental drift is based on the idea that the continents move individually.

Many scientists have come to the point of accepting both these ideas. The evidence on hand now seems to them to require that the earth’s surface has shifted as a whole and that continents have also changed their positions relative to one another.

Up to the present those who have accepted both ideas have not connected them. They think of them as independent processes acting simultaneously. A few writers have suggested that perhaps continental drift causes polar wandering.

This book advances the notion that polar wandering is primary and causes the displacement of continents.

Those geologists who have accepted polar wandering and continental drift, or only continental drift, put the last such change at a long time ago.

This book will present evidence that the last shift of the earth’s crust (the lithosphere) took place in recent time, at the close of the last ice age, and that it was the cause of the improvement in climate.

Two kinds of evidence are responsible for these changing ideas. New knowledge of geomagnetism, or the polarization of rocks of the earth’s crust by the earth’s magnetic field, has led to the discovery that the poles have changed their places on the surface of the earth at least 200 times since geological history began. There is little doubt now but that when we have the complete list it will be twice as long, or even longer.

The other new body of knowledge has come from new methods of dating events in the past by the use of radioactive isotopes of a number of elements. An isotope of carbon (C¹⁴, called radiocarbon) has enabled us to find reliable dates for geological events back to about 65,000 years ago. Isotopes of other elements are good for dating events two or three hundred thousand years in the past. Still others date rocks hundreds of millions of years old.

With these radioactive dating methods it has been possible to reconstruct the climatic history of the earth in great detail for the last hundred thousand years. That is what I shall try to do in this book.

Some of the results of the chronology of the glacial epoch worked out here are surprising. For example, I have found evidence of three different positions of the North Pole in recent time. During the last glaciation in North America the pole appears to have stood in Hudson Bay, approximately in Latitude 60° North and Longitude 83° West. It seems to have shifted to its present site in the middle of the Arctic Ocean in a gradual motion that began 18,000 or 17,000 years ago and was completed by about 12,000 years ago.

The radioactive dating methods further suggest that the pole came to Hudson Bay about 50,000 years ago, having been located before that time in the Greenland Sea, approximately in Latitude 73° North and Longitude 10° East. Thirty thousand years earlier the pole may have been in the Yukon District of Canada.

These ideas are new, and they will at first seem strange, but if the reader will plow through the necessary factual detail presented in this book, he may find sufficient proof.

WHEN it comes time to write an acknowledgment of the assistance 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 advantage. 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 inspired persons, who, by themselves alone, have persevered against odds to complete an imperishable product. This distorts 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 organizers of materials prepared by others. The raw materials, the component elements that have made these great achievements possible, have been contributed by hundreds or thousands 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 question 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, 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 ice caps may have frequently capsized the earth, for many suggestions 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 College, 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 specialists 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 the late 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 scientific 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 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 trying 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 specialists and friends helped us with particular problems. Suggestions were contributed by Professor Frank C. Hibben, of the University of New Mexico, Professor P. W. Bridgman, of Harvard, Dr. John M. Frankland, of the Bureau of Standards, Dr. George Sarton, Professors Walter Bucher and Marshall Kay of Columbia University, Dr. John Anthony 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 to discuss 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, Doctor Anthony has helpfully criticized parts of the manuscript and has helped me to get criticism from other experts. Captain Charles Mayo, of Provincetown, Massachusetts, in many long discussions over the years, has contributed innumerable valuable suggestions.

One farsighted scientist without whose generous help this book in its present form would have been impossible is David B. Ericson, marine geologist of the Lamont Geological Observatory. He has contributed many vitally important bibliographical suggestions, has corrected numerous technical errors, and has 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 vocabulary and for weaknesses in presentation. I have received invaluable 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. Ilse Politzer for the translation from the German of Einstein’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 innumerable 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 grateful for her help.

Grateful thanks are extended to all publishers and individuals who have consented to the use of selections or illustrations, and in particular to the following:

Columbia University Press, for quotations from George Gaylord 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 (paperbound, $2.45); W. H. Freeman & Co., for quotations from Krumbein and Sloss, Stratigraphy and Sedimentation ; Alfred A. Knopf, Inc., for quotations from Hans Cloos, Conversations 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 Structure of the Earth; Science, for quotations from various issues of this magazine; William Sloane Associates, Inc., for quotations from Thomas R. Henry, The White Continent (Copyright 1950 by Thomas R. Henry); University of Chicago Press, for quotations from various issues of the Journal of Geology.

In the new, revised edition of EARTH’S SHIFTING CRUST under the title The Path of the Pole I am especially indebted to Mr. Oppé and Mr. Delair for the great contribution they have made in researching the difficult field of Pleistocene history in South America, and to Fred Earll for his foreword, to say nothing of his helpful advice in preparing this edition. I should also thank those hundreds of research workers who have, by their efforts in geophysical research and in the extension of our knowledge of the past through the new techniques of absolute dating, made possible my own work.

“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:

“ ‘Bay challenging an axiom!’ ”

Lincoln Steffens, Autobiography (p. 816)

WHAT do we mean by polar wandering? This phrase may mean several different things. It may be thought to mean a shift in the position of the axis of the earth. Everyone has seen pictures of the solar system, with the earth, the other planets, and the 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. Any change in this angle, in the position of this axis, would be very important for 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 suggested, for the reason that no force capable of shifting the axis has ever been imagined, other then, possibly, a major planetary collision.

A second way of shifting the poles would be not to change the direction of the axis (let it point to the same stars as before) but merely to shift the earth around on its axis so that different places on its surface would be at the poles. This suggestion also has run into difficulties. The main obstacle to such a shift is the stablizing effect of the equatorial bulge of the earth. The earth is not a true sphere, of course, but a slightly flattened spheroid. The polar flattenings are balanced by a bulge at the equator. The diameters of the earth through the poles and through the equator differ by about 13 miles. The extra mass around the equator, rotating at a very rapid rate, acts like the rim of a gyroscope to keep the earth steady on its axis. The earth is not absolutely steady—it wobbles a little, its off-center path having an average radius of about 50 feet and completing a cycle in about 14 months. But this wobble is not important for us in the present discussion.¹

During the nineteenth century some of the titans of geology, including James Clerk Maxwell (296) ² and Sir George Darwin (son of Charles Darwin), considered this problem, and they decided that the stabilizing effect of the equatorial bulge was so great that no conceivable force originating within the earth could make it shift on its axis. They therefore dismissed the idea of any shift of the poles as impossible and, in fact, not worth discussing. Their influence was sufficient to make sure that nobody until now would seriously consider polar shifts.³

A third way to conceive of polar wandering is through the sliding of the earth’s whole outer shell over semiliquid layers below. This idea was suggested long ago, like most good ideas, but the fellow who first advanced the notion, Damian Kreichgauer (256), did not have enough influence to impose the idea on his contemporaries. This theory requires only two things: first, that the material under the earth’s rigid crust (more properly called the “lithosphere”) be sufficiently liquid, and second, that there should be available a force sufficient to set. the outer shell in motion and keep it moving for considerable distances.

Still another way to change the positions of the poles relative to the continents is to move the continents. This is now a very popular way of explaining things, and we shall discuss it below. However, first we must ask: What is the evidence that the poles really have changed their positions, in one way or another, relative to the various parts of the earth’s surface, especially the continents? People have been claiming to have evidence of such changes for a hundred years, but only recently have we obtained evidence that really seems indisputable. The new evidence has come from studies of the past history of the earth’s magnetic field.

The magnetic field of the earth is what influences the compass to point north. The compass needle does this because it is composed of iron, and iron is a magnetic substance; that is, a substance which will itself become magnetic when exposed to a magnetic field, and will therefore align itself with the lines of force of the earth’s field. What is true of iron in the compass needle is also true of the iron in rocks composed of minerals containing iron.⁴ The tiny iron particles in these rocks also take on a magnetization; they become miniature compasses lined up with the earth’s magnetic field.

The compass needle, if it is free to move in all directions (vertically as well as horizontally), will start pointing gradually downward as the ship or plane bearing the compass approaches the north or south magnetic pole. At the north magnetic pole its north-pointing end will point straight down, and, of course, its south-seeking end will be pointing straight up. At the South Pole this would be reversed. At the magnetic equator the compass needle would lie level.

Fig. 2. Pole positions determined from European rocks of Tertiary and Quaternary Periods.

When iron-bearing rocks have become magnetized they are actually more informative than the mariner’s compass. They indicate the direction of north as the ship’s compass does. But by the angle of their dip they also indicate how far away the pole is. This means they indicate the latitude. The horizontal angle is called variation; the dip is called inclination. The variation gives the longitude of the sample relative to the present magnetic pole, and the inclination gives the latitude. The magnetic rocks adopt the direction of the earth’s field at the time that they are formed, and in many cases they preserve their directions of magnetization indefinitely.

Fig. 3. Pole positions determined from European rocks of Mesozoic Era.

Of course, there are many problems. Local movements of the crust may invalidate the evidence by moving the slab of rock containing the sample hundreds of miles along a major fracture, like the San Andreas Fault in California. The sample, through deep burial, might have been subjected to heat and pressure sufficient to destroy its magnetization or alter the direction of its field. There are other factors that may operate to invalidate a sample. Most of these, however, being local, may be eliminated by the simple means of basing estimates of the position of a pole at a particular time on many samples taken from different places far apart, in different countries or continents.

Fig. 4. Pole positions determined from European rocks of Late Paleozoic Era.

Another problem arises from the fact that the magnetic field of the earth does not stay put. It is in constant motion, having, for one thing, a steady westward drift. Geophysicists studying this, however, have concluded that over a period of a few thousand years the earth’s field returns to its original position, and that the average position of the magnetic pole over the whole period will coincide with the earth’s axis of rotation.

It is simply a question, then, of taking samples from a rock thick enough to represent the sedimentation of several thousand years. If the samples come from lava flows, they have to be taken from successive lava flows indicated as having occured fairly close together in time.

Fig. 5. Pole positions determined from European rocks of Precambrian and Cambrian Periods.

When many samples are assembled, and the results are averaged to eliminate the errors due to local factors or to the “secular” variation of the earth’s magnetic field, and when it has become reasonably certain that no factor has intervened to change the original direction of the magnetization, we begin to have a fairly reliable indication of the position of the pole at the time when the rocks were laid down. If we know approximately when they were laid down (dating them by the included fossils or by one of the methods of “absolute” dating now available) we can assign a date to the particular pole position.

Fig. 6. Pole positions determined from Asian rocks of the Ordovician to the Quaternary Period.

It is obvious, from what I have said above, that there are booby traps, so to speak, for the unwary worker in this field. Nevertheless a vast amount of research has been done, and the state of the science has advanced until we can say that the present findings of pole positions are reasonably reliable. Margins of error are usually allowed. They are indicated by “uncertainty ovals” drawn around each pole position. The reader will observe these ovals in Figure 8. Table 1 lists a great many positions for the North Pole, found from samples of magnetic rocks from all the continents (111a:4-46). Each of these positions has been found by averaging the directions from many samples in the same geological formation, or in geological formations of the same age from other localities. The uncertainty ovals are statistically determined and have 95% accuracy. It is the opinion of specialists that the findings are reliable. What the findings indicate is that the poles have changed their positions relative to the earth’s surface many, many times throughout the history of the earth.

Fig. 7. Pole positions determined from Indian rocks of Mesozoic Era and Tertiary Period.

We see that 229 pole positions are indicated on this table. It is assumed that some of these may be duplications; that is, the same pole indicated from different continents, which is shown as a different pole because of continental drift. How many of these poles may be duplicates? In order to reduce the likelihood of duplicates I have listed, in Table 2, the poles found for each geological period from rock samples from one continent only. Since, obviously, the number of poles in any one geological period would have to be at least equal to the highest figure from any one of the continents, I have selected the continent showing the most pole positions for each particular period.

It seems obvious that the number of pole positions so far determined, though large, is not nearly enough for any but tentative conclusions about continental drift. The following table illustrates this by giving the average time intervals between the poles so far determined for the different geological periods.

Fig. 8. Polar wandering curves based on European and North American rocks. (Mean poles based on all determinations are underlined. European poles are denoted by dots and American poles by triangles and crosses.)

It is obvious that such inequalities in average intervals between polar shifts can have no relation to reality. If there is any regularity (even approximate) in the intervals between polar shifts, the minimum period indicated in this table is more likely to reflect the truth than are the very long periods. It is perfectly obvious that for very long remote geological periods we have virtually no evidence. For the Pleistocene it seems we have an average interval of about 70,000 years between polar shifts. I shall show, in the following chapters, that this may not be very far from the mark. The very long intervals indicated for the older geological periods I think reflect merely our lack of information.

In this book I will give special attention to recent geological time; that is, to the Pleistocene Epoch. It is commonly thought that no polar shifts could have occurred in this recent period. It is the general impression that the poles have been in their present locations for at least several million years. Magnetic evidence in contradiction of this view, however, now exists. This evidence has resulted from studies of volcanic deposits in Japan by Nagata, Akimoto and others (318b) and from Soviet studies (249a). The Japanese samples were taken from the Omura-Yama group of volcanoes in the North Izu and Hakone volcanic region on the east coast of Honshu. Table 4, below, gives positions of the North Pole during the Pleistocene Epoch in reverse chronological order, beginning with the most recent based on Japanese rocks. Column 3 gives the radius of the oval of 95% certainty for each position. No precise datings of the different lava flows were possible. It is therefore not possible to average out the secular variations of the magnetic pole positions indicated, and they do not necessarily indicate the positions of the geographic poles. In some cases they may indicate the temporary position of the pole at the time of a lava flow, when the pole was actually in motion from one position to another.

It is interesting to note that Table 4 indicates that a complete reversal of the earth’s magnetic field occurred twice during the period.

The authors, attempting to interpret the data of this table as a continuous curve, state: “On smoothing out the fluctuations whose periods are shorter than the period of each volcanic activity, the position of the north pole of the geomagnetic centered dipole can be estimated to have shifted from 72° N, 86° E to 81° N, 32° W during the whole Quaternary period” (318b:263). This interpretation of their data will be discussed below (Chapter VII, page 183).

The Soviet findings, as given in Table 5, are not nearly as complete, and their chronological order is uncertain. Nevertheless they indicate considerable displacements of the north magnetic pole.

The geomagnetic data from older geological periods discussed above (Figs. 2-8, pp. 5-13) have inspired geologists to attempt to construct curves for the path of the pole for tens or hundreds of millions of years. It seems to me that the evidence is insufficient for the construction of curves in the older periods. It appears that even in the short period of the last million years such a curve can be constructed only at the cost of sacrificing much of the detail of the evidence. I do not think that those who assume this sort of progressive pole wandering over considerable periods have stopped to work out the logical consequences of their assumptions. What does the idea of a curve involve?

In the first place it involves a continuous motion, or, in the case of interruptions or standstills, the resumption of the motion in more or less the same direction. Changes of direction would have to be gradual in order to give us the long, smooth curves indicated by the authors of the diagrams. We must remember that if the lithosphere is set in motion over the asthenosphere immense forces have been involved. A powerful momentum has been transferred to the lithosphere. An equal force will be required to stop it. But stop the lithosphere did, each and every time after a shift, long enough to form the sedimentary rocks that were to become magnetized in the direction of the earth’s magnetic field at the time. It is obvious from the methods used in the fieldwork that the polar positions were stable for periods of thousands of years, just as they have been in our day ever since men began to make astronomical records in Egypt and in Babylon.

What is the probability that after the lithosphere had been brought to a halt, with each stand still lasting an unknown—perhaps considerable—length of time, that it would resume motion in the same or very nearly the same direction? And what sort of force within the earth could act intermittently in this way? The mechanism I propose to suggest a little later on in this chapter will be one that can account for the starting and stopping of the movements, but it is one that will not act continually in the same direction. According to it, the path of the pole would more likely be a sort of zigzag, with the direction of each new movement determined by the balance of forces within the earth at the particular time. The zigzag path would tend to insure the pole’s remaining within the general area for a considerable time and taking long periods of time to migrate great distances. In Chapters IV, V, and VI and VII I shall present evidence to demonstrate this very sort of motion of the pole in the Pleistocene Epoch.

There are three possible interpretations of the geomagnetic evidence. We can assume polar wandering, continental drift, or a combination of the two. But in order to be able to judge the relevant evidence we must, before we proceed, take a look at what is known about the inside of the earth, where unknown forces have operated to bring these things about.

There is not much that we know about the inside of the earth, because we are unfortunately restricted to living on the outside of it. We must deduce what we know from mining and oil drilling activities, seismic waves from earthquakes or artificial explosions, and principles of physics. The subject is wrapped in uncertainty. Therefore, it is natural that there should be differences of opinion—opposing groups of scientists devoted to different notions. However, among the uncertainties there are some points on which most scientists are agreed. I will confine myself here to giving in a condensed form the consensus of geological opinion on the structure of the earth.

Alfred Wegener, who first drew attention to the idea of continental drift, was a good scientist, though not a geologist. He had found quantities of evidence of fossil flora and fauna that could not, in his opinion, be reconciled with the present positions of the poles. Inasmuch as the authorities, such as George Darwin and Maxwell, forbade any thought that the axis 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 as polar shift, for it would mean that at different times the same areas might be found in very different latitudes.

Wegener imagined that the continents, formed of light sedimentary and granitic rocks, were floating in the heavier basaltic material of the ocean bottoms. He thought he saw evidence, in the shapes of the continents, that they had once formed a single land mass, which had split so that pieces could go drifting off over the ocean bottoms. He thought of the ocean bottoms as composed of soft, amorphous or viscous rock. From a vast amount of fossil evidence of the plant and animal life of the past he imagined that he could reconstruct the paths of the continents over long periods of time. He proposed to explain the mystery of ice ages by this theory. He suggested that during the last ice age in the Northern Hemisphere, Europe and America had lain together near the North Pole, but that since then they had drifted away from the pole and each other.

Wegener’s theory had great appeal—not because all the evidence supported it, not because the authorities were open-minded about it, not 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.

A number of weaknesses in this theory were gradually revealed. As knowledge of the ocean bottoms increased it was discovered that the rock under the oceans, which Wegener thought to be plastic enough for the continents to drift over it, was in fact very rigid, and indeed stronger than the rocks of the continents. This meant that the continents could not drift without displacing and pushing to one side a layer of rigid rock estimated to be twenty miles thick. It therefore seemed to be impossible for continents to drift. Jeffreys, basing his opinion on the evidence for a rigid and comparatively strong ocean floor, said, “... There is therefore not the slightest reason to believe that bodily displacements of continents through the lithosphere are possible” (239:346). The geophysicist F. A. Vening Meinesz, according to Umbgrove, conclusively proved the considerable strength of the crust under the Pacific (420:70).

Another weakness that appeared in the Wegener Theory was in its assumption that the ocean bottoms were smooth plains.