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 enormous volume from a deep core of greater density into these portions of an originally lighter crust. ..." (420:235-36).
Barrells suggestion points to the chief weakness of the geophysical argument in favor of the permanence of the continents, whether or not they drift. As I have already pointed out, geophysicists seem, too often, to take as the frame of reference only the outermost ten miles or so of the lithosphere. Theoretically they base their calculations on the full depth of the lithosphere, but practically this assumption is canceled out by the assumption that the lithosphere 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 lithosphere are taken into account, the difficulties in the face of the subsidence and elevation of continents vanish, and the theory of continental drift becomes superfluous.
THE EXTINCTION OF THE MAMMOTHS
AND THE MASTODONS
When this theory of crustal displacements 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 observation. 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 opposite side of the earth. He asked me whether there was evidence of this. I said I thought there was. I am presenting the evidence here.
The closing millennia of the ice age saw an enormous mortality 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, including mammoths, mastodons, giant beaver, sabertooth cats, giant sloths, woolly rhinoceroses. Camels and horses apparently became extinct in North America then or shortly afterward, 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 revolution had a profound effect upon animal life, and occasioned or at least accompanied, the great estinctions, which, at the end of the Pleistocene, decimated the mammals over three-fifths of the earths land surface (372:75).
No one has been able to explain these widespread extinctions. 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 Asiathat is, both in the area presumably moved southward and in the area presumably moved northwardI 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 pictures of it drawn by primitive man have been found in the caves of southern France and Spain; but most of all, perhaps, because some 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 numerous in the New Siberian Islands, which lie between the Arctic coast of Siberia and the pole. Secondly, they are accompanied 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 good enough conditions 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 mammoths alleged 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 mammoths 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 dermatologist 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 both animals made their hair less resistant to cold and damp than the hair of the average mammal. In other words, the hair and fur of the mammoth 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; it 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. [Neuvilles footnote here : It is merely necessary to mention 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 with an oily liquid, protecting it also against desiccation and disintegration ... 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 impermcability, 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 points out 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 that protection from damp is more important than protection from low temperature. Oil in the hair must certainly impede the penetration 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: Many animals of the equatorial jungles, such as tigers, have 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 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 inquiries 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 inquiry to them regarding the effects of natural oil secretions 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 maintenance of the fleece in an orderly and hence more efficacious state (447).
It appears that there has been no scientific study of the precise points at issue here; no one has measured in any scientific 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 rejecting 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 mammoths 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 contrary, 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 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-protection 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 insulation 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, remarked 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 assumption 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, however, have to be an Arctic winter. A Winter such as we have in temperate climates is quite cold enough to cut the available food supply for herbivorous animals. It seems that under favorable circumstances even the African and Indian elephants accumulate quite a lot of fat. F.G. Benedict, in his comprehensive work on the physiology of the elephant, considers it a fatty animal (26).
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 corresponding 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 were 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.
The people who lay the greatest stress on the adaptation of the mammoth to cold ignore the other animals that lived with the mammoths. Yet we know that along with the millions of mammoths, the northern Siberian plains supported 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 does it do to argue that the mammoth was adapted to cold when it is impossible to use the argument in the case of several 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, Nordenskjöld made the following observations of monthly averages of daily Centigrade temperatures during the year along the Lena River (334):
January -48.9 (-56 F.)
February -47.2 (-52F.)
March -33.9 (-40 F.)
April -14 (+ 7F.)
May - 0.4 (+32F.)
June +13.4 (+56F.)
July +15.4 (+60 F.)
August +11.9 (+53F.)
September + 2.3 (+36 F.)
October -13.9 (+ 7F.)
November -39.1 (-36F.)
December -45.1 (-49F.)
The average for the whole year was -16.7 (+2° F.). It appears that only three months out of the year are reasonably free from frost. Even so there must be frequent frosts in July, notwithstanding the occasional high midday temperatures. High temperatures on some days would bring the monthly mean down, even if night frosts continued through July.
No doubt it was knowledge of these conditions that caused the great founder of modern geology, Sir Charles Lyell, to remark that it would doubtless be impossible for herds of mammoths and rhinoceroses to 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 remains of mammoths and other animals are most numerous of all. There Baron Toll, the Arctic explorer, found remains of a sabertooth tiger, and a fruit tree that had been ninety feet tall when it was standing. The tree was well preserved in the permafrost, 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 remains 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 mainland, 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 Nordenskjöld 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 thousands 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 direction 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. Occasionally perhaps an animalif for some reason it did not happen to sink, if it were not eaten by fishesmight be washed up on the shore of one of the islands. It seems probable that only a very powerful current could transport the body of a mammoth across 200 miles of ocean.
But let us suppose that somehow the animals are transported 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 o€ 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 90-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 insist that they were always as cold as they are today. Thus it is not a question at all of whether the climate grew colder but merely a question of when the change occurred.
Campbell has contributed a suggestion with regard to the alleged floating of hundreds of thousands of bodies across the Nordenskjöld Sea. He notes that bodies ordinarily float because of gas produced by decomposition. Decomposition 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. There is an old saying in the lake region that "Lake Superior never gives up its dead." The Arctic Ocean is much colder than the waters of Lake Superior. The water of the Lena would not be warm even in midsummer, but during the spring floodswhen the Lena would be swollen with the melt water of the winter snowsthe water would be frigid, and the bodies of animals drowned in it would not decompose, nor would they float. They would tend to sink, instead, into the nearest hole and perhaps never come to the surface.
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 involved. 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.
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 snowfields, 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 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 suggested above. That this is the explanation for the preservation 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 accounted 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 consistently 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 permafrost. Among them have been found the enormous numbers of mammoths tusks already mentioned. To be of any use for carving, tusks must either come from freshly killed animals 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 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 mammoth 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 tile 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 condition would speedily deteriorate the quality of the ivory (280:363).
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 statement. I shall try to show later on how all the details of the phenomena he describes can be made understandable. For the moment, I would like to point out simply that some sort of abrupt climatic change is required. This conclusion is reinforced by the results of recent research in the frozenfoods 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 preservation of meat by freezing requires some rather special conditions. 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 Birdseyes 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 illuminating. Quoted by Bassett Digby in his book on the mammoth, Herz said that "the flesh is fibrous and marbled with fat" It "looks as fresh as well frozen beef." And this remark is made about 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 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 1930s (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 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 0° 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 escape 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 remains are often found at high pointson the highest points of the tundra (412:51). He notes that the bodies are found in frozen ground, not in ice, and that they must have been buried in mud before freezing. This presents a serious problem because, 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 pemianently frozen ground, could exist only in quite exceptional conditions (412:57).
Howorth remarked on this same problem :
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 entombed, 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 (225a:313).
Since Tolmachev can think of no other solution to this problem, he finds himself forced to conclude that the mammoths 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 summer, 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 sudden, indeed, must it have been ? How can we account for it on the assumption of a comparatively slow displacement of the earths 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 considerably since the experiments conducted by Birdseyes engineers. In an article in Science, Maryman summarizes the more 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, "Lovelock considers -5° C. as the lowest temperature to which mammalian cells may be slowly frozen and still survive." Furthermore the tissues survive gradual freezing very well :
In most, if not all, soft tissue cells there is no gross membrane rupture 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 historological appereance is often indistinguishable from the normal (304:518-19).
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 play sical presence of extracellular ice crystals, but the denaturation incurred by the dehydration resulting from the incorporation of all free water into ice (ibid.).
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 freezing.
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 (ibid.).
I am reminded, in writing these lines, of my experience in truck gardening. In trying to reduce damage from frost, I 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 frostedeven 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, growing into large ones in the hour or so before the sun was up far enough to melt them may have 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, followed by a sharp fall in temperature. Whenever the meat was preserved in an edible condition the deep freeze must have been uninterrupted; there mast 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.
Perhaps the most famous individual mammoth found preserved in the permafrost was the so-called Beresovka mammoth. 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. Petersburg. 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 distinguished academicians entrained at St. Petersburg and proceeded 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 he 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 noticing 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 position. Strangely enough, the animals 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 animals tongue and between his teeth, indicating an abrupt interruption of his last meal. The preliminary onclusion suggested by these facts was that the animal met his death by falling into the river.
Very special interest attached to the analysis of he contents of this animals 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, published 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 reproduce the stomach analysis by V.N. Sukachev, with omission of technical botanical terms where possible, and with omission of bibliographical references to Russian, German, and Latin sources, and some shortening of the comment (400).
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 belong. ...
Measurements of the individual parts of these plants, when compared 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 arc 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 specimens 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 district. ... 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 anatomical 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. ... Generally 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 numerous 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 Pyrenees. 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. [Omittedapparently 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) Tranty. In the contents of the stomach were found several fragments of these beans. ... In the fragments 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 described 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 61st parallel of latitude and to the marshlands of northern Europe. Both of them "belong 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 mammoths mouth, between its teeth, were the same as the stomach contents, and represented 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 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, suggest 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."
A vital prerequisite for any correct interpretation of the facts in this case is information on the age of the mammoth. This information was not available when the first edition of this work went to press, but is now at hand. It comes as a great surprise to those, like myself, who assumed that the mammoth must have died during the time that Siberia was moving northward in accordance with the crustdisplacement hypothesis; that is, between approximately 12,000 and 18,000 years ago. The age of the mammoth, however, turns out to be at least 39,000 years, and possibly as much as 47,500 years.
Where does this leave us ? Can we fit this into our scheme ? It appears from this timing (which there is no reason to doubt) that the Beresovka Mammoth died when the climate in Siberia was warming upafter the pole had left the Greenland Sea and migrated to America. His death occurred at a time when we would assume that there was a high turbulence of climatic conditions, and when the level of earthquakes and volcanic eruptions would be at a peak. Since the warming of the climate had probably been going on for several thousand years herds of mammoths and other animals would have been moving northward into areas where the grasslands and forests had been reestablished.
And it was in the middle of this warming trend in Siberia, when the climate was warmer there than it is now, and right in the middle of the summer, that the mammoth died, and his body was immediately frozen ! And somehow or other it remained frozen all through the period of about 30,000 years when we have shown through much evidence that the Arctic Ocean was warm and luxuriant forests were growing along the Arctic coasts.
The evidence for the warm Arctic that we have presented in earlier chapters is overwhelming, and it tics in with the evidence we have produced for a warm Antarctic at the same time. It cannot be dismissed just because one mammoth (and a few other animalssee the table below) wanted to stay frozen for the whole period that the Arctic was warm. But it certainly is not easy to see how those bodies could have been kept in deep freeze for such a length of time when the climate of the region where they lay entombed was warm. Offhand one would be tempted to shout that the thing was impossible.
Of course there has to be a way out. Three or four bodies are not going to bulldoze us into giving up the assumption of the warm Arctic that is supported by so much evidence.
But if we are going to hold to our assumption of a warm Arctic, how are we going to explain the Beresovka Mammoth ? Perhaps we can do it this way :
The evidence shows that the animal suffered a very severe fall, severe enough to break his pelvis and leg. We learn also that the food in his stomach and mouth did not match the vegetation around him at the spot where he was found. He did not fall into water, because, as was ascertained by another investigator, large masses of his blood were found under him. The blood would, of course, have been washed away had he tumbled into a river. The fact that his penis was found to be erect indicates that he was not instantly killed by his fall, but that he froze to death. He was certainly plunged suddenly into extreme cold.
I think we can see how this might have happened. With a high level of earthquake activity large fissures could be opening in the crust in considerable numbers, as they commonly do in many earthquakes. Let us assume that the mammoth fell into one of these.
We must remember that according to our theory a long period of intense cold had gripped the Siberian coast until only a short while before. This would have been the time of the pole position in the Greenland Sea. The situation of the pole just north of Norway would have logically involved an ice age in the region of the Beresovka River. The frozen ground, or permafrost, of this ice age might have extended down thousands of feet, as it does today in some places in the Arctic. When the pole moved to Hudson Bay the climate in the Beresovka region would have become about like that of Minnesota today, where the winters are severe enough to prevent, or greatly delay, the deep melting of a permafrost extending down thousands of feet.
We may suggest, then, that the Beresovka Mammoth fell into a deep crevasse or fracture in the earths crust, perhaps several hundreds of feet deep. He might have tumbled down a sloping wall of the crevasse a long way without actually killing himself, but of course at the bottom loose earth dislodged by his fall could have cascaded down upon him and buried him alive. According to biologists I have consulted the erection of the penis could have resulted from the poor animals emotions of terror and from his pain.
The mammoth might have frozen to death and afterwards been gradually frozen through in the manner I have suggested in the preceding pages. The fissure would very likely have been largely filled in as the result of continuing earth shocks, landslides and the like, and then gradually the temperature of the body would have been reduced to the low temperatures prevailing deep in the permafrost.
And what of that great fissure ? What is the existing evidence of it ? Why, the valley of the Beresovka River itself ! The valley, or channel, of the present river may have been created by the filling in of the fissure.
But how then, you may ask, did the mammoth come to the surface? The answer may be that erosion in the valley was rapid during the ensuing warm period because the river must have been much better fed by its tributaries then than it is now. Moreover it is generally thought that the coast stood higher then, than now, so that the New Siberian and Liakov Islands were connected with the mainland. The result of these factors would probably have been that the river was much larger and flowed much faster than now, and consequently in the 30,000 years or so of the warm period could have eroded the valley to a very considerable depth.
The Beresovka Mammoth, and the other bodies we have of about the same age, might thus have been brought nearer the surface but not actually uncovered until after the climate again grew cold with another poleward shift of Siberia.
The following table shows that warming periods after glaciationsthat is, after crust displacementshave been just as fatal to species of animals as periods of increasing cold. I feel that this is because they succumbed to the turbulence of the climate, to the furious storms, to the abrupt changes of temperature caused by massive volcanism, to hurricanes, dust storms, torrential rains and unseasonable snows that probably decimated their food supplies. In America, after all, the horse, mastodon, mammoth and other ice-age animals died out as the climate was warming up. We shall see in the next chapter that cold climate had nothing whatever to do with the massive extinctions of animals in South America at the same time.
Of course, most of the animals found frozen in the Arctic do date, as Table 20 shows, from the end of the Wisconsin glaciation to the time when we assume Siberia was moving northward, and the refrigeration of the climate does account for the good preservation of the mammoth ivory. At the same time, the turbulence of the climatic conditions accounts for the fact that few entire bodies are found. The remains are for the most part just bones scattered about and piled in great heaps, together with heaps of frozen trees. These contribute an air of violence and tragedy to the endless reaches of the desolate tundra.
I have referred to the possibility that the extinction of animals and preservation of their bodies may be accounted for in part by violent atmospheric disturbances, and I have offered some evidence that such disturbances did accompany the last displacement of the crust and therefore, presumably, earlier displacements.
It may be hard to distinguish between the effects on animal 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, 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 faunal population. ...
The Alaskan muck is like a fine, dark gray sand. ... Within this mass, frozen solid, lie the twisted parts of animals and trees intermingled 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 Hibben writes :
The Pleistocene period ended in death. This is no ordinary extinction 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 Wilshire 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 evidence.
It might at first appear that many of these great animals died 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 literally thousands of these remains together. The young lie with the old, foal with dam and calf with cow. Whole herds of animals were apparently 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 simply 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).
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 ice cap, whether thin or thick. 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, earthshaking 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 be preserved at all. Bodies that die and lie on the surface soon disintegrate and the bones are scattered. A volcanic eruption would explain 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 atmospheric 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 mammoth 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 ligaments 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 violence. 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 Chapter IX 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 reinforces the suggestions advanced by Hibben, and at the same time his evidence strongly supports our theory. But Hibben points out certain consequences that would flow from our theory, which I have not stressed. Wherever 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 IX, that they apparently occurred 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 importance to the meteorological results of the universally acting volcanic dust. As we have noted, this dust has a powerful effect in reducing the average temperatures of the earths 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 epizootic diseases. Then the dust could greatly increase rainfall, which, in certain circumstances would produce extensive floods, thus drowning numbers of animals and perhaps piling their bodies 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 everywhere. 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 suffocation. 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 accumulating tensions in the crust, accompanied by terrific earthquakes and by sudden changes of elevation locally amounting perhaps 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.
It is little wonder that, faced by all these unpleasant conditions, a good many species in all parts of the world, even very far from the ice caps, 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 coincident with the southward displacement of North America at the end of the last North American ice age.
1. A number of additional considerations are pertinent to the question of the process of preservation of the mammoths.
It appears that the size of the meat unit is an important factor. According to a Science Service dispatch from Washington, published in the Boston Globe November 11, 1957:
"Both cut-up and pre-cooked poultry are less stable than whole, un-cooked poultry when it comes to undesirable changes. ..."
It seems that 50° F. would stop the digestive juices.
At 0 F. freezing would be at the rate of one inch an hour with direct contact of the snow with the skin. Here the amount of protective fat on the stomach might be a factor.
It is clear that very low temperatures are required for long-term preservation of meat. However, it is also true that protection of the carcasses from oxygen is essential. The exteriors of many carcasses may spoil, and yet the interiors may last a long time.
2. This turned out to be incorrect (see below).
3. One of my correspondents, Alf H. Hostmark, sent me a quotation from the German edition of a work by Wegener and Koppen, which I translate as follows :
"The mammoth ezcavated by Herz and Pfizenmayer in the middle Kolyma region in 1901 lay in a depression in ... fossil ice which was evidently an old glacial remnant into which it had been thrust; great masses of frozen blood had flowed from the severe wounds it had suffered in its fall."