It differs from that genus, in having four, instead of five toes, and in having only one on the fore-feet elongated, while the pteropus has but one short toe, and all the rest elongated. The skeleton is ten inches four-twelfths long, and is imbedded in limestone, by whose contraction it appears to have been somewhat compressed and distorted. The skull is remarkably small, while the jaws are longer than the body, and furnished with sharp slightly bent teeth. The neck is as long as the body, and composed, as in most mammiferous quadrupeds, of seven vertebræ. There are four limbs, having four toes on each; one of the toes on the anterior limbs is very much elongated, while the other three are short. All the toes have claws; the toes of the hind, are longer than those on the fore-feet. No tarsal bones were found along with the metatarsal and claws; it is possible the tarsal bones may have decayed. The animal had a distinct tail. The head bears a very considerable resemblance to that of a woodcock; the enormous jaws, and the sharp teeth, remind one of the crocodile, or alligator. Sommering is inclined to believe, from the structure of the mouth and teeth, that this singular creature fed on large insects, which it caught while on the wing, and that its power of flying must have been considerable.

We shall conclude this very imperfect sketch, by giving a short account of a few fossil animals belonging to the class of oviparous quadrupeds, found in the Maestricht quarry, and in England.

The animal found in the Maestricht quarry was ascertained by Cuvier to have been a monitor, a genus of the lizard tribe, intermediate to those which have a long and forked tongue, and those which have a short tongue and the palate armed with teeth. The skeleton was about twenty-four feet long. The head is one-sixth of the length of the whole body; a proportion ap-. proaching that of the crocodile, but different from the monitor, whose head is but one-twelfth of the length of the body. The tail of this animal must have been a broad and powerful oar, enabling it to move with security and ease amidst the most turbulent waters. From various circumstances connected with these bones, which we need not here detail, Cuvier concludes that this huge creature was an inhabitant of the ocean, although none of the existing lizard tribe are known to inhabit salt water. A tooth which belonged perhaps to an individual of the same species, was found at the foot of the Neversink Hills, in New-Jersey, and is figured in Mitchill's interesting additions to Cuvier's Theory of the Earth. The specimen is deposited

in the valuable cabinet of the Lyceum of Natural History of New-York.

The animals of this class discovered in England, are the ichthyosaurus, plesiosaurus, and megalosaurus. All of them have some analogy with the crocodile, but approach also the structure of fishes. The megalosaurus is the most remarkable of them all; its skeleton is estimated at upwards of sixty feet in length, and its bulk must have equalled that of an elephant seven feet high. Its head terminated in a flat, straight, and very narrow snout; it was provided with paddles of vast size; and like the great monitor heretofore mentioned, it is more than probable that the megalosaurus was a tenant of the briny deep, where it was only equalled or exceeded in size by the largest whales.

Thus, we see that in the animal kingdom changes of the most wonderful character have at some very remote points of time occurred. Proof of an irrefragable kind, is offered us from all parts of the world hitherto explored, that animals once existed, which have been entirely extinct for ages beyond all human tradition or record. If the mastodon, the megatheria paleotheria, gigantic tapir, or gigantic bear, had ever been known, even to the rudest and most savage of mankind, some tradition, however wild, some echo, however faint, would have been continued to the remotest posterity. Neither is there the slightest ground for believing that these great extinct genera and species could, in any way, have been the originators or sources of creatures at present existing. We have no trace of intermediate species; and we are satisfied that many genera at present existing, were cotemporary with some of the extinct genera, as we find their bones together, and under precisely the same conditions as to age, &c. To satisfy ourselves on this point, it is unnecessary to do more than refer to what occurs in nature at the present time; we do not find species in a state of domestication, or in their savage condition, gradually blending together. The horse does not mingle with animals not of his own kind-and when he does procreate an offspring with an animal of his own kind, but of a different species, as the ass, the mule produced is sterile, and unable to extend the confusion and irregularity. Climate, exposure, and peculiarities of diet, are able to produce great external differences or varieties, even in animals of the same species. The colour and quality of the hair; the quantity of ivory produced; the texture of the skin, &c., may all be affected to a considerable degree. Yet the important characteristics, which may be considered as the indication of the nature of the animal, are not in the slight

est degree affected by time, climate, nor accident, but are continued from generation to generation, unchanged in the slightest peculiarity.

Anxious to examine this subject in the fairest and amplest manner, M. Geoffroy St. Hilaire, the highly distinguished naturalist and philosophical anatomist, obtained for Cuvier, during the time he was in Egypt, all the mummies of animals that were to be gathered from the pyramids and catacombs. Among these were the ibis, cats, dogs and heads of the ox. If it were possible that species could change during a lapse of time, certainly this was a fair opportunity for testing the truth, as the most recent period to be assigned to these mummies could not be less than three thousand years. But, on the most careful and faithful examination, it was impossible to discover the smallest difference between these mummies and their congeners existing at the present day. The ibis which wheels along the banks of the Nile, is at the present moment, exactly the same as its predecessors in the days of the Pharaohs. The same may be said of human mummies, which show us no greater difference between the men of antiquity and those now living, than may be found in individuals of the same country, or of different nations. If a lapse of three thousand years be insufficient to produce the slightest specific change in the structure of animals, of what avail is Mr. Ranking's proofs that Genghis killed elephants, or that the Romans slew wild beasts wherever they were established. Why talk to us of the Mongol having carried elephants into Siberia, and of elephants being able to stand the climate? Do we not see in the same genus, the wolf howling under the influence of famine near the pole, and the jackal yelping in crowds after the wild buffalo' in the hottest parts of Asia and Africa? And is it not the case with multitudes of other genera? and occasionally, individuals of the same species, are found throughout every variety of climate, from the equator to the poles. Yet no changes of place or climate, produce changes of generic or specific structure; the fossil elephants found in Europe and America are specifically, that is organically, different from the elephants now obtained from Asia and Africa. The Mongolians and Romans obtained their elephants from Asia and Africa, even subsequent to the Christian era, and therefore, the elephants thence obtained could not have furnished the bones of the fossil species. The bones of man, under equal circumstances, are as enduring as those of other animals; repeated observations upon former fields of battle, prove that the bones of the horseman suffer as little from the vicissitudes of seasons, as those of his steed. Thousands of men and

horses perished at the same time, and in the same places with the elephants; yet hath not one solitary human bone been discovered along with them—and very rarely those of the horse. But bones of the hippopotamus, whale, dolphin, rhinoceros, and other animals, have been, in numerous instances. We might admit, that some of the bones found near where Roman stations once were held, might have been of animals killed by them, if they were not mingled with bones of creatures so strikingly different in character, that the Romans could not have possessed such, without having left some record of the fact. But when we look abroad upon the earth, and learn from the few and partial explorations which have yet been made, that the organic remains of hosts of beings have been discovered, plants, shells, fishes, reptiles, quadrupeds, almost innumerable, wonderful in structure and of mighty size, which by some desolating power have been swept into nothingness, we shall be inclined to smile at the Mongolian conquerors and their elephants, no less than at the "king-citizens" of Rome and their life-consuming amphitheatres.

These considerations might be infinitely strengthened, by a full examination of the soils in which the most remarkable of these fossils have been found. The changes which take place in most of them, are such as to require great lapses of time for their accomplishment, and would fix the dates of their formation in the earliest infancy of our globe. But we have already said so much, without being able to do more than glean here and there a few scattered portions of the evidence against our author's conclusions, that we shall relinquish the inquiry for the present; under the full conviction, that if the ingenious author of the "Historical Researches," would devote half as much time to the study of the facts collected in relation to general fossil zoology, as he has employed on that work, he would be one of the first to look with doubt or pity upon the doctrine he has with so much zeal attempted to enforce.

ART. V.-An Essay on the Doctrine of Contracts; being an Inquiry how Contracts are affected, in Law and Morals, by Concealment, Error, or inadequate Price. By GULIAN C. VERPLANCK. New-York, 1825. 8vo. pp. 234.

THE learning and industry of the American lawyer have been repeatedly exercised in the republication of professional works, with such additions as were proper to render them more useful to the American student; but an original treatise on the science of jurisprudence is a rare occurrence with us. It is a field on which genius and knowledge may be profitably employed; but it must be done with infinite caution and discretion. The peculiar situation of our country; the nature of our government; the habits and manners of our people, certainly require, and have already induced, many changes in the laws which govern in Europe; and particularly in the kingdom whence we are immediately derived. Untrammelled by the usages and prejudices of ages, we are able to receive improvements, which would not be admitted in older communities. In Pennsylvania, various beneficial alterations have been made, not only in the practice of the courts in the administration of the laws, but in some essential principles of jurisprudence. We have gone on slowly and cautiously, relying on long experience, not sudden emergencies or brilliant speculations, for our guide, and the result has seldom disappointed the anticipation.

On the other hand, nothing can be more unwise and dangerous than a wild, ungoverned spirit of innovation in the law. We must not break down established principles, long acted upon as land-marks of right, to indulge fanciful theories; much less to exhibit a rash courage of affected independence, or a foolish ambition to show we are all-sufficient for ourselves. It is the great privilege of a new people to profit by the experience of those who have gone before; and it is their highest wisdom to make use of it without either a slavish, indolent subserviency, or a reckless rejection of its lessons. We should be particularly vigilant and cool, when we would attempt any change in the English law. It is not only woven in all our institutions and systems of jurisprudence, but may be said to be a part of ourselves. On a question of property, we can hardly think out of it; to demolish it would break up the very foundations of society. Some inflated, dreaming politicians, build beautiful systems in their visions, and believe that, if all we have were swept away, they would produce a more admirable substitute. But let them beware; and let us beware how we