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.

Mr. Pengelly thinks it possible, but not proved, that the lower
breccia of Kent's Cavern may be interglacial or preglacial in age. One
case only is known where a human bone has been found in a cavern under
deposits supposed to be of the nature of the glacial drift. It is that
of the Victoria Cave, at Settle, in Yorkshire. At this place a human
fibula was found under a layer of boulder clay. But there are too many
chances of this bone having come into this position by some purely
local accident to allow us to attach much importance to it until
future discoveries shall have supplied other instances of the
kind.[138]

I may close this survey of the cave deposits with a summary of the
results of M. Dupont, as obtained from two of the caves explored by
him, that of Margite and that of Frontal. In the first of these
caverns, resting on rolled pebbles which covered the floor, were four
distinct layers of river mud deposited by inundations, and amounting
to two yards and a half in thickness. In all of these layers were
bones. The lowest contained rude flint implements, and bones of the
mammoth, rhinoceros, bear, horse, chamois, reindeer, stag, and hyena.
In the overlying deposits are some flint implements of more artistic
form and a greater prevalence of the bones of the reindeer. In the
second cave, that of Frontal, over a similar deposit of alluvial mud
of the mammoth age, was found a s