d
into the cave from without.

The next bed marks a new change. It is a layer of black mould from
three to ten inches thick. Its microscopic structure does not seem to
have been examined; but it is probably a forest soil, introduced by
growth, by water, by wind, and by ingress of animals, all of them
modern, and contains works of art from the old British times before
the Roman invasion up to the porter bottles and dropped half-pence of
modern visitors. Lastly, in and upon the black mould are many fallen
blocks from the roof of the cave.

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 cont