warring with the more cultivated denizens of plains below, which are now deep under the waters. Their weapons, and other implements dropped in the cavern or lost in hunting, or buried in the flesh of wounded animals which crept to the streams to assuage their thirst, are those found in the cave earth. The absence of the human bones may merely show that the mighty hunters of those days were too hardy, athletic, and intelligent often to perish from accidental causes, and that they did not use this cavern for a place of burial. The fragments of charcoal show that they were acquainted with fire, and possibly that they sometimes took shelter in the cave. But the land again subsided. The valley of that now nameless river, of which the Rhine and the Thames may have alike been tributaries, disappeared under the sea; and perhaps some tribe, driven from the lower lands, took up its abode in this cave, now again near the encroaching waves, and left there the remains of their last repasts ere they were driven farther inland or engulfed in the waters. For a time the cavern may have been wholly submerged, and the charcoal of the extinguished fires became covered with its thin coating of clay. But ere long it re-emerged to form part of an island, long barren and desolate; and the valleys having been cut deeper by the receding waters, it no longer received muddy deposits, and the crust formed by drippings from its roof contained only bones and pebbles washed by rains and occasional land floods from its own clay deposits. Finally, the modern forests overspread the land, and were tenanted by the modern animals. Man returned to use the cavern again as a place of refuge or habitation, and to leave there the relics contained in the black earth. This seems at present the only intelligible history of this curious cave and others resembling it; though, when we consider the imperfection of the results obtained even by a large amount of labor, and the difficult and confused character of the deposits in this and similar caves, too much value should not be attached to such histories, which may at any time be contradicted or modified by new facts or different explanations of those already known. The time involved depends very much on the answer to the question whether we should regard the postglacial subsidence and re-elevation as somewhat sudden, or as occupying long ages at the slow rate at which some parts of our continents are now rising or sinking.