The American Quarterly Review, No. 17, March 1831

by Various

In all the regularly stratified formations, animals of the mammiferous or cetaceous classes are wholly wanting; at least we have no proof that can be relied upon of any having been found in formations which took place prior to the last great deluge, that covered so much of the land with diluvium. In this last formation, however, they are often found in great abundance. Some of them are of recent, others of extinct species. Among the most remarkable of the latter are, the palæotherium, and anoplotherium, found near Paris; the megalonyx, an animal of the sloth genus, but of the size of an ox, found in Virginia; a still larger sloth, called the megatherium, found near Buenos Ayres; the fossil elephant, as different from the living elephants of India or Africa, as the horse is from the ass, and which has been found in Europe, in Asia, and in America. The mastodon, of which several species have been discovered on the banks of the Hudson, in Kentucky, in Louisiana, in the plains of Quito, in France, and finally on the borders of the Irrawaddy.

The bones of rhinoceroses, bears, elephants, and hyænas, have been found mixed in confusion in caverns; and it has been shown by Buckland that the latter animal had inhabited these caverns, and drawn thither the carcasses of the others as his prey, in one of the most perfect inductive arguments which has been produced, since Bacon propounded the rules of that species of reasoning.

"The moveable earths that fill the bottoms of valleys, and which cover the surface of great plains, have furnished us in the above two orders, of pachidermata and elephants, the bones of twelve species, to wit: one rhinoceros, two hippopotami, two tapirs, an elephant, and six mastodons. All these twelve species are now absolutely extinct in the climates in which their bones are found. The mastodons alone may be considered as forming a separate genus, now unknown, but closely approaching to the elephant. All the others belong to genera now existing in the torrid zone. Three of these living genera are now found only in the ancient continent, to wit: the rhinoceros, the hippopotami, and the elephant; the fourth, that of the tapirs, only exist in the new. The distribution of the fossil species is different; the tapirs have been found only upon the old continent, while elephants have been discovered in the new."

The fossil species, although belonging to known and existing genera, are essentially different in species from those which now live upon the earth. The former are not mere varieties, but have marked specific differences. This at least is beyond all doubt in respect to the smaller of the hippopotami, and the gigantic tapir, as well as the fossil rhinoceros, and is extremely probable in respect to the elephant and the smaller tapir. If there be any question of the fact, it is only in respect to the greater hippopotamus.

"These different bones are buried in all different places in beds that resemble each other. They are often mixed indiscriminately with those of other animals, identical with those which exist at present. These beds are generally moveable, sandy, or marly, and always within a short distance of the surface. It is therefore probable that these bones have been enveloped by the last catastrophe of the globe. In a great number of places, they are accompanied by the accumulated spoils of marine animals; in other places, but these are less numerous, the remains of marine animals are not found, and sometimes the sand or marle that covers them contains only fresh-water shells. Although a small number of shells attached to fossil bones indicate that, they have remained some time under water, yet is there no authentic account of their having been found covered with regular stony beds, filled with marine remains, nor, in consequence, is there any proof of the sea having made a long and peaceable stay above them.

"The catastrophe that has covered them, would appear then to have been a great marine inundation, of no long duration, were it not that they are found upon the tops of high mountains, whither the waters of our present ocean could never have reached in their most violent agitations. On the other hand, these bones presenting no appearance of having been rolled, being occasionally only fractured, as the remains of our present domestic animals may occasionally be, and being sometimes found in entire skeletons, and accumulated as if in a common cemetery, demonstrate that the living beings to which they have belonged, must have met their fate in the very parts of the globe in which we now find the fossil monuments of their existence."

All the animals of which we have particularly spoken, are of genera now only found in the torrid zone, and the abundance of food which their great size would have caused them to require, renders their existence in numbers only possible in a warm climate. Their remains are, however, found in almost polar regions, whence we obtain a third link in the chain of evidence, that before the last great catastrophe to which the globe was subjected, its surface must have been warmer than at present.

We have seen in a former place, that such a change of temperature may have gradually occurred in consequence of a cooling of the external surface of the globe by an excess of its radiation above the quantity of heat received from the sun. The final cooling of its solid crust, down to the mean temperature at which we now find it, might, as is obvious, have been effected by a great irruption of waters, like that of which we have distinct evidence in the diluvial deposits, and the animal remains upon its surface. From that time, a state of equilibrium in the action of solar and terrestrial radiation having been attained, while the mean temperature still continues to depend upon the internal structure and nature of the globe, the distribution of heat upon the surface, and the vicissitudes of the seasons, have been solely influenced by the varying relation between these two radiations, which if equal to each other in their total amounts, differ in every different latitude, for every successive day in the year, and during each varying hour of the day.

It has been attempted to explain this change that has unquestionably taken place in the temperature of climate, by conceiving a change in the situation of the earth's axis. This hypothesis, however, is shown to be untenable by the calculations of physical astronomy: no other cause then remains but an actual change in the condition of the earth itself.

The most remarkable of all the phenomena which the earth presents, are the great changes of weight that have taken place in identical formations which must have arisen from the prevalence of water, and therefore nearly if not exactly upon the same level. The primitive or lowest stratified rocks, probably had not water for their cause; still, however, they must have been in the fluid state, and these are not only found beneath all other rocks, and in the lowest places to which the industry of man has penetrated, but they also rise and form the greatest part in bulk of many of the highest mountains; indeed, if we except volcanic mountains, of all the more elevated masses. The transition and secondary formations are subject to similar although less changes of level, rising, as has been seen, to the tops of the Pyrenees, and to even a greater height on the sides of the Andes. The tertiary or superior formations are found in Italy and Sicily, forming mountains several thousand feet in height, while the latest of all, the diluvial with its embedded mammalia, exists in the lofty table land of Quito. The inference is irresistible, that we do not now find these deposits at the levels where they were left by the ocean, as in the case of the primitive rocks by their own crystallization from a fluid state, but that they have been altered in their positions by actions of a character totally distinct from that by which they were originally formed.