The rock in which the cavern, mentioned in the title of this paper, is formed, is that species of limestone called Oolite. Its greatest length is from 250 to 300 feet, and its breadth and height vary from two to seven feet, there being few places in which it is possible to stand upright. Its bottom was covered by a sediment of mud, and the roof and sides, as well as the surface of the mud, were incrusted by stalactitic matter. The animal remains were found, not upon the surface, but in the lower part only of this muddy deposit, and in the stalagmitic accumulations beneath it, and were thus remarkably preserved from decay. The teeth and bones hitherto discovered are those of the hyaena, fox, bear, of an animal of the tiger kind, of the elephant, rhinoceros, hippopotamus, and horse, of the ox and some species of deer, of the water rat and the rabbit. They were strewed promiscuously over the bottom of the cave ; the bones, with very few exceptions, being broken and apparently gnawed ; for upon many of them marks were detected fitting the form of the canine teeth of the hyaenas that were found there ; whence it appears probable that this was once a den of hyaenas, who dragged into its recesses the other animal bodies, whose remains are mixed indiscriminately with their own; a conjecture, says the author, rendered almost certain, by the discovery of a portion of solid calcareous excrement, recognized by the keeper of the Menagerie at Exeter ’Change, from its resemblance to that of the Cape hyaena; the analysis, too, of this excrement shows its derivation from bones, as it consists chiefly of phosphate and carbonate of lime. It appears from the researches of M. Cuvier, that the fossil hyaena was nearly one third larger than the largest of the modem species, of the habits of which the author gives an account, with a view of verifying and illustrating his opinion concerning the state and origin of the contents of the Yorkshire cave. Even the abundance of the remains of water rats, he says, is consistent with the omnivorous appetite of modern hyaenas. In respect to ruminating animals, as they form the ordinary food of beasts of prey, the quantity of their bones is not surprising; but the abundant occurrence of some of the other remains, in a cave of the dimensions of that described, is not so obvious ; since such animals as the elephant, rhinoceros, and hippopotamus, could not possibly have found an entrance, and since it is foreign to the habits of the hyaena to prey on the larger pachydermata. As a solution of this difficulty, the author supposes that the remains in question are those of individuals who died a natural death; and though the hyaena would neither have had strength to kill an elephant or rhinoceros, nor to drag home the entire carcase of a dead one, yet he might convey the most bulky animals piecemeal into his den, supposing them to have died in the neighbourhood. From this view of the subject it appears probable that the accumulation of these bones went on during a succession of years, while the animals in question were natives of this country; and the general dispersion of similar bones through the diluvian gravel of high latitudes, over a great part of the northern hemisphere, shows that the period at which they inhabited these regions was that immediately preceding the formation of this gravel, and that they perished by the waters that produced it. Moreover, as all these animals belong to species now unknown, and as there is no evidence of their ever having existed subsequent to the formation of the diluvium, we may conclude that the period at which the bones were introduced into the Kirkdale cave was antediluvian. That these extinct species never re-established themselves after the deluge, seems proved by the total absence of their remains in the varieties of postdiluvian accumulations of sand, mud, and peat, in which, however, we find the remains of horses, deer, and some other animals.