possessed of ten infinities of fingers and toes is in no respect an absurdity. Of the three infinities possible in space, the second is infinitely greater than the first, and the third infinitely greater than the second. A line infinitely produced is capable of being divided into--that is, consists of--an infinity of given parts; a plane infinitely extended is capable of being divided into an infinity of infinitely divisible lines; and a cube, that is, a solid, infinitely expanded, is capable of being divided into an infinity of infinitely divisible planes. In fine, metaphysic theology furnishes no argument against the infinite series of the atheist. But geology does. Every plant and animal that now lives upon earth began to be during the great Tertiary period, and had no place among the plants and animals of the great Secondary division. We can trace several of our existing quadrupeds, such as the badger, the hare, the fox, the red deer, and the wild cat, up till the earlier times of the Pleistocene; and not a few of our existing shells, such as the great pecten, the edible oyster, the whelk, and the Pelican's-foot shell, up till the greatly earlier times of the Coraline Crag. But at certain definite lines in the deposits of the past, representative of certain points in the course of time, the existing mammals and molluscs cease to appear, and we find their places occupied by other mammals and molluscs. Even such of our British shells as seem to have enjoyed as species the longest term of life cannot be traced beyond the times of the Pliocene deposits. We detect their remains in a perfect state of keeping in almost every shell-bearing bed, till we reach the Red and Coraline Crags, where we find them for the last time; and, on passing into older and deeper lying beds, we see their places taken by other shells, of species altogether distinct. The very common shell _Purpura lapillus_, for instance, is found in our raised beaches, in our Clyde beds, in our boulder clays and mammaliferous crags, and, finally, in the Red Crag, beyond which it fails to appear. And such also is the history of the common edible mussel and common periwinkle; whereas the common edible cockle, and common edible pecten (_P. opercularis_) occur not only in all these successive beds, but in the Coral Crag also. They are older by a whole deposit than their present contemporaries, the mussel and periwinkle; and these, in turn, seem of older standing than shells such as _Murex erinaceus_, that has not been traced beyond the times of the mammaliferous crag, or than shells such as _Scrobicularia piperata_, that has not been detected in more ancient deposits than raised sea beaches of the later periods, and the elevated bottoms of old estuaries and lagoons. We thus know, that in certain periods, nearer or more remote, all our existing molluscs _began_ to exist, and that they had no existence during the previous periods; which were, however, richer in