There can be no doubt that this cave and the neighboring one of Brixham have done very much to impress the minds of British geologists with ideas of the great antiquity of man; and they have, more than any other postglacial monuments, shown the existence of some animals now extinct up to the human age. Of precise data for determining time, they have, however, given nothing. The only measures which seem to have been applied, namely, the rate of growth of stalagmite and the rate of erosion of neighboring valleys, are, from the very sequence of the deposits, obviously worthless; and the only apparently constant measure, namely, the fall of blocks from the roof, seems not to have been applied, and Mr. Pengelly declares that it can not be practically used. We are therefore quite uncertain as to the number of centuries involved in the filling of this cave, and must remain so until some surer system of calculation can be devised. We may, however, attempt to sketch the series of events which it indicates. The animals found in Kent's Hole are all "postglacial," some of them of course survivors from "preglacial" times, and some of them still surviving. They therefore inhabited the country after it rose from the great glacial submergence. Perhaps the first colonists of the coast of Devonshire in this period were the cave bears, migrating on floating ice, and subsisting like the arctic bear and the black bear of Anti-costi, on fish, and on the garbage cast up by the sea. They may have found Kent's Hole a sea-side cavern, with perhaps some of its galleries still full of water and filling with breccia, with which the bones of dead bears became mixed. In the case of such a deposit as this breccia, however, the precise time when its materials were finally laid down in their present form, or the length of time necessary for its accumulation, can not be definitely settled. It may be a result of continued torrential action or of some sudden cataclysm. As the land rose, these creatures for the most part betook themselves to lower levels, and in process of time the cavern stood upon a hill-side, perhaps several hundreds of feet above the sea; and the mountain streams, their beds not yet emptied of glacial detritus, washed into it stones and mud, and probably bones also, while it appears that hyenas occupied the cave at intervals, and dragged in remains of mammals of many species which had now swarmed across the plains elevated out of the sea, and multiplied in the land. This was the time of the cave earth; and before its deposit was completed, though how long before an unstratified and therefore probably often-disturbed bed of this kind can not tell, man himself seems to have been added to the inhabitants of the British land. In pursuit of game he sometimes ascended the valleys beyond the cavern, or even penetrated into its outer chambers; or perhaps there were even in those days rude and savage hill-men, inhabiting the forests and