Fishes occur in one of the fresh-water deposits of the Paris basin ; and these are therefore properly ranked in this division, whatever may be judged respecting others where the nature and origin of the strata are still obscure. But it must be remarked that geologists have sometimes bewildered themselves in these questions, from their pecu liar views respecting the origin and nature of such depo sits: difficulties which time and further acquisitions of knowledge must be expected to remove. The amphibia that are found in several of the strata may possibly also be considered with some propriety as of terrestrial origin, in at least most instances, as was just remarked in speaking of the marine amphibia ; but respecting the individuals yet known, re cannot at present have any demonstration on this subject : as the crocodiles and the obscure animals apparently belonging to this tribe that have been brought to light may, for aught we yet know, be, like the sea turtles, or the lizards of the Pellew islands, marine and amphibious, and not the inhabitants of fresh waters.
If the plants which occur most commonly imbedded in the solid strata cannot properly be considered as aquatic, they arc chiefly such as, from their general characters, and from the manner in which they are included in the rocks, must be considered as the inhabitants of the borders of lakes, or of boggy and marshy situations. The perfect preservation of their delicate forms proves that they can not have undergone transportation, and that they are pre served where they lived and died. Yet there do also ex ist in many rocks, fragments of trees and other vegetable remains, which appear more strictly terrestrial, as will hereafter be noticed. It need scarcely be said, that the plants preserved in peat are here excluded fiom both the divisions of terrestrial vegetable remains ; although the lignites, belonging as much to the alluvia as the bones of quadrupeds do, are included.
Those terrestrial organic substances which may be con sidered as properly terrene, are presumed to be so from their natures, not from their situations, as they are some times found imbedded in strata of aquatic origin as well as in alluvial deposits, and occasionally in company with aquatic, in some cases, indeed, even with marine remains. They comprise quadrupeds, birds, reptiles, insects, and plants ; and they bring us down to the last periods of the earth's changes, which connect the most ancient living be ings with those which are actually in existence.
Remains of quadrupeds of various extinct genera or species, together with those of some birds and reptiles, are found accompanying fishes and shells in the fresh water deposits of the Paris basin. These are also accumulated
in caverns or fissures, as we formerly remarked, being more or less entangled in earthy matters. Lastly, they are found imbedded in alluvial soils, under various circum stances of great interest ; of which one of the most re markable is that already mentioned as existing in Italy. Under this head also may be included the animals en tangled in ice, which were mentioned before in describing the strata. Of some of these, indeed, it is even yet un certain whether they may not still be existing in the living state in the remote recesses of countries very little known to us.
It had been supposed by some persons, that the ele phants found in Italy might be the remains of those used by Hannibal in his wars against the Romans, or of those which this people kept for ornament, or luxury, or for the spectacles of their amphitheatre. But that hypothesis has been very properly abandoned, since the nature of this country has been more accurately investigated. It is besides, now well known, that the same animal is found in the northern parts of Europe, as in Germany. There is indeed sufficient proof, that some species of elephant in habited those countries in ancient times. Besides those specimens now found in the alluvial soils, almost all the ancient Scandinavian or Runic monuments preserve the figure of this animal in their sculptures ; an emblem of something, it must be supposed, the intention and nature of which is now unknown, as it is always united to many other emblematical figures. The monumental stones of Scotland, which are apparently of northern origin, display this figure almost invariably ; and it has been a sore diffi culty to antiquaries, who have sought for its origin among the Romans to little purpose. Thus the study of this de partment of geology illustrates a circumstance in the his tory of these northern usages, which is otherwise inexpli cable ; while' that of antiquities, in return, assists in esta blishing a dubious geological fact.
The preservation of terrestrial insects in a fossil state is so rare an occurrence as scarcely to deserve notice in a collection of geological appearances. That they have not been oftener preserved, must be probably. however, attri buted to their minuteness and to their perishable nature, rather than to their former rarity. We shall hereafter have occasion to describe the very few of these facts that are known.