42. This period has been marked by one of the greatest inundations which have ever visited the globe, which changed once more the aspect of its surface, and destroyed completely a multitude of living species, of which only few remains have been found. Everywhere are left traces which attest its generality. The water, violently driven from its bed, has surrounded continents, drawing with them Earth and rocks, denuding mountains, and uprooting forests of a century’s growth. The new deposits which they have formed are designated in geology “diluvial terrains.”
43. One of the most significant traces of this great disaster are rocks called “erratic blocks.” Thus are named granite rocks that are found isolated in plains reposing upon tertiary beds, and in the midst of diluvial rocks, sometimes many hundred of miles from mountains whence they have been torn. It is evident that they can have been transported so great a distance only by the violence of a current. *
* It is one of these blocks, evidently by its composition coming from the mountains of Norway, which serves as the pedestal to the statue of Peter the Great at St. Petersburg.
44. A no less characteristic fact, and one the cause of which is not yet explained, is that among the diluvial rocks are found the first aerolites. It is, then, at this epoch that they began to form. The cause which produced them did not previously exist.
45. It is toward this epoch that the poles commenced to be covered with ice, and the glaciers were formed on the mountains, which indicates a notable change in the temperature of the globe. This change must have been sudden; for, had it operated gradually, animals, such as the elephant, which live now only in warm climates, and which are found in great numbers in a fossil state in the polar territories, would have had time to withdraw little by little, to the more temperate regions. Everything goes to prove that they have been suddenly seized by great cold, and enveloped in ice. *
* In 1771, the Russian naturalist Pallas found in the midst of the ice from the North the entire body of an elephant fossil, covered with its skin, still maintaining part of its flesh. In 1799, another elephant fossil was found and described by the naturalist Adams. It was equally immersed in a huge block of ice, near the mouth of the Lena River, in Siberia. The people who lived in the neighborhood (Jakoutes) tore its flesh apart to feed their dogs. Its skin was covered with a long mane and the neck was covered with thick fur. The head, not including the tusks, measured more than 3 meters and weighed more than 400 pounds. Its skeleton is at the museum of Saint Petersburg. On the island and on the beaches of the glacial ocean large quantities of tusk are found, which constitute objects of considerable commerce under the name of ivory fossil, or ivory from Siberia.
46. This was, then, the veritable universal deluge. Opinions are divided as to the cause which produced it; but, whatever they may have been, the fact no less exists.
It is generally supposed that a sudden change took place in the position of the axes of the Earth, by which the poles were displaced, whence a general projection of the water upon the surface. If this change had come about gradually, the waters would have been displaced by degrees without agitation; whilst everything indicates a violent and sudden commotion. While in ignorance of the veritable cause, one can give only hypothesis.
The displacement of the waters can have been occasioned only by the uprising of certain parts of the solid crust, and the formation of new mountains on the bosom of the waters, like that which took place at the commencement of the tertiary period; but, beyond there having been a general inundation, this would explain nothing of the sudden change of the temperature of the poles.
47. In the agitation caused by the displacement of the waters, many animals have perished; others, in order to escape inundation, have withdrawn to the high elevations, into caves and crevasses, where they have perished in masses, perhaps by famine, perhaps by devouring one another, or by the flowing of the water into the places where they have taken refuge, and from whence they could not escape. Thus is explained the cause for the great quantity of bones of animals, carnivorous and otherwise, which are found mixed-up in certain caves, named by reason of this “bone caverns.” They are found most frequently under the stalagmites. In a few of them the bones seem to have been drawn there by the current of the waters. *
* A great number of similar caverns have been discovered, of which some are quite extensive. There exist some in Mexico which are many miles in extent. That of Adelsberg, in Carniola, Austria, is no less than nine miles. One of the most remarkable is the Gailenreuth, in Wurtemberg. There are many in France, England, Germany, Sicily, and other countries of Europe.