Other theories of equally hypothetical nature were proposed; but the phenomena held responsible for the changes have not been proved to have existed, or to have been able to produce the effect.
All the above-mentioned theories and hypotheses fail if they cannot meet a most important condition: In order for ice masses to have been formed, increased precipitation must have taken place. This requires an increased amount of water vapor in the atmosphere, which is the result of increased evaporation from the surface of
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oceans; but this could be caused by heat only. A number of scientists pointed out this fact, and even calculated that in order to produce a sheet of ice as large as that of the Ice Age, the surface of all the oceans must have evaporated to a depth of many feet. Such an evaporation of oceans followed by a quick process of freezing, even in moderate latitudes, would have produced the ice ages. The problem is: What could have caused the evaporation and immediately subsequent freezing? As the cause of such quick alternation of heating and freezing of large parts of the globe is not apparent, it is conceded that "at present the cause of excessive ice-making on the lands remains a baffling mystery, a major question for the future reader of earth's riddles." 1
Not only are the causes of the appearance and later disappearance of the glacial sheet unknown, but the geographical shape of the area covered by ice is also a problem. Why did the glacial sheet, in the southern hemisphere, move from the tropical regions of Africa toward the south polar region and not in the opposite direction, and, similarly, why, in the northern hemisphere, did the ice move in India from the equator toward the Himalaya mountains and the higher latitudes? Why did the glaciers of the Ice Age cover the greater part of North America and Europe, while the north of Asia remained free? In America the plateau of ice stretched up to latitude 40° and even passed across this line; in Europe it reached latitude 50°; while northeastern Siberia, above the polar circle, even above latitude 75°, was not covered with this perennial ice. All hypotheses regarding increased and diminished insolation due to solar alterations or the changing temperature of the cosmic space, and other similar hypotheses, cannot avoid being confronted with this problem.
Glaciers are formed in the regions of eternal snow; for this reason they remain on the slopes of the high mountains. The north of Siberia is the coldest place in the world. Why did not the Ice Age touch this region, whereas it visited the basin of the Mississippi and all Africa south of the equator? No satisfactory solution to this question has been proposed.
1 R. A. Daly, The Changing World of the Ice Age (1934), p. 16.
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The Mammoths
Northeast Siberia, which was not covered by ice in the Ice Age, conceals another enigma. The climate there has apparently changed drastically since the end of the Ice Age, and the yearly temperature has dropped manv degrees below its previous level. Animals once lived in this region that do not live there now, and plants grew there that are unable to grow there now. The change must have occurred quite suddenly. The cause of this Klimasturz has not been explained.
In this catastrophic change of climate and under mysterious circumstances, all the mammoths of Siberia perished.
The mammoth belonged to the family of elephants. Its tusks were sometimes as much as ten feet long. Its teeth were highly developed and their "density" was greater than in any other stage in the evolution of the elephants; apparently they did not succumb in the struggle for survival as an robin-bobin
unfit product of evolution. The extinction of the mammoth is thought to have coincided with the end of the last glacial period.
Tusks of mammoths have been found in large numbers in northeast Siberia; this well-preserved ivorv has been an object of export to China and Europe ever since the Russian conquest of Siberia and was exploited in even earlier times. In modern times the ivory market of the world still found its main source of supply in the tundras of northeast Siberia.
In 1799 the frozen bodies of mammoths were found in these tundras. The corpses were well preserved, and the sledge dogs ate the flesh unharmed. "The flesh is fibrous and marbled with fat" and 'looks as fresh as well frozen beef." 1
What was the cause of their death and the extinction of their race?
Cuvier wrote of the extinction of the mammoths: "Repeated irruptions and retreats of the sea have neither all been slow nor gradual; on the contrary, most of the catastrophes which have occasioned them have been sudden; and this is especially easy to be proved with regard to the last of these catastrophes, that which, by a twofold
1 Observation of D. F. Hertz in B. Digby, The Mammoth (1926), p. 9.
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motion, has inundated, and afterwards laid dry, our present continents, or at least a part of the land which forms them at the present day. In the northern regions it has left the carcasses of large quadrupeds which became enveloped in the ice, and have thus been preserved even to our own times, with their skin, their hair, and their flesh. If they had not been frozen as soon as killed, they would have been decomposed by putrefaction. And, on the other hand, this eternal frost could not previously have occupied the places in which they have been seized by it, for they could not have lived in such a temperature. It was, therefore, at one and the same moment that these animals were destroyed and the country which they inhabited became covered with ice.
This event has been sudden, instantaneous, without any gradation, and what is so clearly demonstrated with respect to this last catastrophe, is not less so with reference to those which have preceded it." 2
The theory of repeated catastrophes annihilating life on this planet and repeated creations or restorations of life, offered by Deluc 3 and expanded by Cuvier, did not convince the scientific world. Like Lamarck before Cuvier, Darwin after him thought that an exceedingly slow evolutional process governs genetics, and that there were no catastrophes interrupting this process of infinitesimal changes. According to the theory of evolution, these minute changes came as a result of adaptation to living conditions in the struggle of the species for survival.
Like the theories of Lamarck and Darwin, which postulate slow changes in animals, with tens of thousands of years required for a minute step in evolution, the geological theories of the nineteenth century, and of the twentieth as well, regard the geological processes as exceedingly slow and dependent on erosion by rain, wind, and tides.
Darwin admitted that he was unable to find an explanation for the extermination of the mammoth, an animal better developed than
2 Cuvier, Essay on the Theory of the Earth, pp. 14-15.
SJ. A. Deluc (1727-1817), Letters on the Physical History of the Earth
(1831).
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the elephant which survived.* But in conformity with the theory of evolution, his followers supposed that a gradual sinking of the land forced the mammoths to the hills, where they found themselves isolated by marshes. However, if geological processes are slow, the mammoths would not have been trapped on the isolated hills. Besides, this theory cannot be true because the animals did not die of starvation. In their stomachs and between their teeth undigested grass and leaves were found. This, too, proves that they died from a sudden cause. Further investigations showed that the leaves and twigs found in their stomachs do not now grow in the regions where the animals died, but far to the south, a thousand or more miles away. It is apparent that the robin-bobin