Among the extinct animals which modern research has brought to light, the megatherium, from mega great, and therion wild beast, is the most remarkable for its colossal size and extraordinary proportions. It may not, perhaps, strictly belong to the period under consideration, and indeed the general inference is, that it existed subsequently to the extinction of the palæotherium, and the other strange quadrupeds buried in the supracretaceous rocks of Europe, but it is too remarkable a character to be omitted in our retrospect of the early inhabitants of the earth, and is, moreover, deserving of attention from the interesting inferences to be adduced from its peculiar organization. Only two individuals of this species of animal have been discovered, but from the fortunate circumstance of one having been found almost entire, naturalists have been able to investigate its structure with more precision than that of many others, whose remains, though existing in greater abundance, are generally dispersed. The discovery of this interesting skeleton was entirely accidental. A peasant passing along the river Solado, near Buenos Ayres, threw his lasso at something which stood half-concealed in the stream, and dragged on shore the enormous pelvis of the animal. This led to a further search, the river was diverted from its course by means of a dam for that purpose, and the rest of the bones with the teeth and claws, imbedded in a stratum of blue clay, through which the river had cut its channel, were soon brought to light and transferred to Madrid, where, the several portions having been carefully put together and the animal anatomically re-constructed, this "mighty pre-Adamite" now forms the most remarkable feature of the royal museum.

The megatherium, although of such gigantic dimensions, is considered to have been a species of sloth, with a maily covering like the armadillo. Cuvier calls it the "paresseux géant," and inferred from its organization, that like the sloth it fed upon vegetables, but while the one lived upon leaves the other fed upon roots. Buffon and other naturalists have regarded the organization of these animals as imperfect, and considered them clumsy performances of nature, in which the inconveniences resulting from deformity were attended, with no compensating advantages. Professor Buckland, in a recent lecture, has shewn the absurdity of this inference, and proved by an admirable train of inferential reasoning, deducing the habits of the extinct animal from its organization, that so far from their being abortions, they are beautiful instances of that richness of contrivance by which all organized beings are adapted to the circumstances in which they are placed, and the part they are destined to perform in the creation. The peculiarities of the sloth, although they unfit it for moving with ease upon the earth, admirably adapt it for its destined residence upon the branches of trees; so the proportions of the megatherium, apparently so anomalous, are exquisitely arranged with a view to its intended subsistence upon those tubercular roots which abound in the countries where its remains were found, and which, from the construction of its grinders, it is inferred, were the food of this animal. "Its teeth," says Dr. Buckland, "though ill-adapted for the mastication of flesh or grass, are wonderfully contrived for the crushing of roots, with the further advantage of keeping themselves sharpset in the very act of performing their work."

I

An idea may be formed of the outline and general proportions of the megatherium, from the subjoined sketch, copied from Cuvier's very accurate drawing.

The animal was about twelve feet long and eight high. The fore feet, nearly a yard in length and exceeding a foot in breadth, were armed with three enormous claws, each more than a foot long, which it is supposed to have constantly employed in scraping roots from the ground, while the weight of its ponderous body rested firmly upon its hinder extremities-the anterior part of the skeleton, it will be perceived, is light and elegant compared with the posterior proportions, which are said to exceed in bulk those of the largest elephant. To this incongruous mass of bones was added a coat of mail, which it is suggested was to protect the animal from the annoyance which the sand and dirt raised in digging for its food would occasion,* or it might have been intended to render the animal invulnerable to all external attacks, whether from venomous insects, to which, in the tropical climates where it existed, it would be exposed, or from

*The armadillos which obtain their food by digging in this manner, are also covered with a maily skin.

beasts of prey, with whom, notwithstanding its colossal size, it was ill-prepared to contend.

Considerations such as these, exhibit in a new and stronger light the beautiful harmony and unity of design which pervades the creation, and gives geology a new claim upon the philosopher and theologian. Thus, while astronomy proves to us that the ponderous orb which hangs in mysterious equilibrium in our system, and the stupendous worlds, which, with the great globe itself, whirl with inconceivable force and never-failing regularity around it, are acted upon and governed by the same laws as those which regulate the apparently capricious motions of the smallest atom which dances in the sunbeam, geology shews us that the same wise contrivance and skill, which characterize the structure of the animated being of to-day, is stamped upon the organic relics of the remotest period of the past. But, reserving for the future these reflections, we must proceed in our examination of the stratified masses, in which new wonders and new objects of admiration will present themselves as we advance.

The supracretaceous rocks, which have perhaps occupied a larger share of attention than is commensurate with their relative importance, or compatible with the plan of this sketch, rest invariably upon that well-known rock-formation the chalk,-an imperfect limestone, distinct alike in its mineral character and fossil contents. The chalk-hills are a remarkable feature in this country, which appear to be the result of a general upheaving of this, * in common with the

* The chalk is almost emblematic of sterility, for, although an enriching manure when combined with strong aluminous soils,

lower strata, the general line of bearing of which throughout this island is from N. E. to S. W. "This," says

Mr. Conybeare," may have been effected, not by a single, sudden, or violent convulsion, but by a gradual, gentle, and protracted upheaving, continued without interruption during the whole period of the formation of all these strata." Although this is generally true, there are in some situations decided marks of violent derangement: for instance, in the Isle of Wight, where the chalk, which must have been originally horizontal, with all its incumbent sedimentary beds of lacustrine and marine origin, similar to those in the Paris basin, have been forced into a vertical position. The chalk is entirely

where it exists in excess, it is universally attended with barrenness, and is generally characterized by a peculiar stunted vegetation. It is to this latter circumstance, according to an eminent geologist, that the origin of the singular custom of the "Chiltern hundreds," the fiction by which Members of Parliament vacate their seats, may be traced. It appears that the Chiltern Hills, a remarkable part of the chalk range in Oxfordshire, were formerly covered with brushwood and thickets, which harboured banditti, whose depredations became so alarming that it was found necessary to institute a permanent local force, for the protection of the lives and property of his Majesty's faithful lieges, over which force presided an officer, appointed by the crown, with the title of Steward of the Chiltern Hundreds. His "occupation" being long since "gone" the office has become a nominal one, the acceptation of which, however, is sufficient to incapacitate a Member from holding his seat in the House of Commons.

* Mr. Conybeare has recently made some interesting observations upon the general lines of disturbance traceable in the chalk formations. He observes that there is a general tendency to