vicissitudes of diluvial and other geological changes have left few and partial illustrations of such finished handiwork of the Drift-folk. Their cave-dwellings did indeed admit, under specially favouring circumstances, of the occasional preservation of bone implements, the smaller knives and lances of flint, and other comparatively delicate objects used in indoor work; and the value of these as illustrations of the habits and usages of the ancient Troglodytes can scarcely be exaggerated. But even those owe their preservation to processes akin to that which fractured and dispersed the fragments of the Brixham Cave implement; and which, in the more violent rearrangement of the river-gravels, must have generally reduced any carved bone or delicately worked flint to indistinguishable fragments. The exceptions indeed are exceedingly rare of finding in the gravel-beds a single bone of any animal so small as man. The caves also undoubtedly embody in the contents of their silt and stalagmite the industrial implements of a later period than that of the river-gravels; and, as in the case of Kent’s Cavern, even preserve the evidence of a succession of occupants belonging to distinct eras, and probably to essentially diverse races of men. But it is only in exceptional cases of special interest that the cave-drift discloses traces of actual habitation, the refuse heaps of the kitchen, the broken or stray tools, and even the flint-cores, hammer-stones, and flint-chips, which indicate the workshop of the ancient tool-maker. Mr. Evans figures hammer-stones of various kinds, made of diverse pebbles and of chipped flint; and others from the French caves consist of flint-cores with the prominent surfaces worn round by their use as hammer-stones in the process of chipping the flint into the desired forms. One of this class of implements now in my possession, of light grey flint, and bearing manifest traces of long use, was turned up in a ploughed field in Licking County, Ohio. Another example in my collection was presented to me by Mr. W. L. Merrin, who picked it up in the vicinity of one of the pits on Flint Ridge, among the broken flakes and nodules which showed where the old flint miner had been at work. The cave deposits embedded animal remains and human implements in part by the same processes which in neighbouring river-valleys were burying the works of man alongside of the bones of the largest fossil mammalia. In the former, at times, the silting up was by a process sufficiently gentle to preserve unharmed the minuter traces of the cave-dweller and his arts; but as a rule there have remained to us from that remote Palæotechnic era, only the larger and ruder implements, corresponding as it were to the axe of the woodman, and the mattock or plough of the field labourer, which were alone capable of withstanding the violence of floods, and the like elements of geological reconstruction.