relations to one another, and to the functions of the animal in which they occur.

Its

The size of the Megatherium exceeds that of the existing Edentata, to which it is most nearly allied, in a greater degree than any other fossil animal exceeds its nearest living congeners. With the head and shoulders of a Sloth, it combined in its legs and feet, an admixture of the characters of the Ant-eater, the Armadillo, and the Chlamyphorus; it probably also still further resembled the Armadillo and Chlamyphorus, in being cased with a coat of armour. haunches were more than five feet wide, and its body twelve feet long and eight feet high; its feet were a yard in length, and terminated by most gigantic claws; its tail was probably clad in armour, and much larger than the tail of any other beast, among extinct or living terrestrial Mammalia. Thus heavily constructed, and ponderously accoutred, it could neither run, nor leap, nor climb, nor burrow under the ground, and in all its movements must have been necessarily slow; but what need of rapid locomotion to an animal, whose occupation of digging roots for food was almost stationary? and what need of speed for flight from foes, to a creature whose giant carcase was encased in an impenetrable cuirass, and who by a single pat of his paw, or lash of his tail, could in an instant have demolished the Couguar or the

Crocodile? Secure within the panoply of his bony armour, where was the enemy that would dare encounter this Behemoth of the Pampas? or, in what more powerful creature can we find the cause that has effected the extirpation of his race?

His entire frame was an apparatus of colossal mechanism, adapted exactly to the work it had to do; strong and ponderous, in proportion as this work was heavy, and calculated to be the vehicle of life and enjoyment to a gigantic race of quadrupeds; which, though they have ceased to be counted among the living inhabitants of our planet, have, in their fossil bones, left behind them imperishable monuments of the consummate skill with which they were constructed. Each limb, and fragment of a limb, forming co-ordinate parts of a well adjusted and perfect whole; and through all their deviations from the form and proportion of the limbs of other quadrupeds, affording fresh proofs of the infinitely varied, and inexhaustible contrivances of Creative Wisdom.

SECTION III.

FOSSIL SAURIANS.

In those distant ages that elapsed during the formation of strata of the secondary series, so large a field was occupied by reptiles, referrible to the order of Saurians, that it becomes an important part of our enquiry to examine the history and organization of these curious relics of ancient creations, which are known to us only in a fossil state. A task like this may appear quite hopeless to persons unaccustomed to the investigation of subjects of such remote antiquity; yet Geology, as now pursued, with the aid of comparative anatomy, supplies abundant evidence of the structure and functions of these extinct families of reptiles; and not only enables us to infer from the restoration of their skeletons, what may have been the external form of their bodies; but instructs us also as to their economy and habits, the nature of their food, and even of their organs of digestion. It further shows their relations to the then existing condition of the world, and to the other forms of organic life with which they were associated.

The remains of these reptiles bear a much greater resemblance to one another, than to those

of any animals we discover in deposits preceding or succeeding the secondary series.*

The species of fossil Saurians are so numerous, that we can only select a few of the most remarkable among them, for the purpose of exemplifying the prevailing conditions of animal life, at the periods when the dominant class of animated beings were reptiles; attaining, in many cases, a magnitude unknown among the living orders of that class, and which seems to have been peculiar to those middle ages of geological chronology, that were intermediate between the transition and tertiary formations.

During these ages of reptiles, neither the carnivorous nor lacustrine Mammalia of the tertiary periods had begun to appear; but the most formidable occupants, both of land and water, were Crocodiles, and Lizards; of various forms, and often of gigantic stature, fitted to endure the turbulence, and continual convulsions of the unquiet surface of our infant world.

When we see that so large and important a range has been assigned to reptiles among the

* The oldest strata in which any reptiles have yet been found are those connected with the magnesian-limestone formation. (Pl. 1, Sec. 16). The existence of reptiles allied to the Monitor in the cupriferous slate and zechstein of Germany, has long been known. In 1834, two species of reptiles, allied to the Iguana and Monitor, were discovered in the dolomitic conglomerate, on Durdham Down, near Bristol.

former population of our planet, we cannot but regard with feelings of new and unusual interest, the comparatively diminutive existing orders of that most ancient family of quadrupeds, with the very name of which we usually associate a sentiment of disgust. We shall view them with less contempt, when we learn from the records of geological history, that there was a time when reptiles not only constituted the chief tenants, and most powerful possessors of the earth, but extended their dominion also over the waters of the seas; and that the annals of their history may be traced back through thousands of years, antecedent to that latest point in the progressive stages of animal creation, when the first parents of the human race were called into existence.

Persons to whom this subject may now be presented for the first time, will receive, with much surprise, perhaps almost with incredulity, such statements as are here advanced. It must be admitted, that they at first seem much more like the dreams of fiction and romance, than the sober results of calm and deliberate investigation; but to those who will examine the evidence of facts upon which our conclusions rest, there can remain no more reasonable doubt of the former existence of these strange and curious creatures, in the times and places we assign to them; than is felt by the antiquary, who, finding the catacombs. of Egypt stored