d, and as a result of this action we have the elaborate and
fantastic stony incrustations termed stalactites and stalagmites. The
water percolating through the rock covers the sides of the cavern with a
stalactitic drapery, and if a line of drops persistently falls from the
same point to the floor, the calcareous deposit gradually descends from
the roof, forming in some cases stony tassels, and in others long
columns which are ultimately united to the calcareous boss formed by the
plash of the water on the floor. The surface also of the pools is
sometimes covered over with an ice-like sheet of stalagmite, which
shoots from the sides, and sometimes forms a solid and firm floor when
the water on which it was supported has disappeared. Sometimes the drops
form a little calcareous basin, beautifully polished inside, which
contains small pearl-like particles of carbonate of lime, polished by
friction one against the other. The most beautiful stalactitic caves in
Great Britain are those of Cheddar in Somerset, Caldy Island and Poole's
Cavern at Buxton. A portion only of the carbonate of lime is thus
deposited in the hollows of the rock from which it was taken; the rest
is carried into the open air by the streams, in part deposited on the
sides and bottom, forming tufa and the so-called petrifications, and
partly being conveyed down to the sea to be ultimately secreted in the
tissues of the Mollusca, Echinodermata and Foraminifera. Through these
it is again collected in a solid form, and in the long course of ages it
is again lifted up above the level of the water as limestone rock, and
again undergoes the same series of changes. Thus the cycle of carbonate
of lime is a neverending one from the land to the ocean, from the ocean
to the land, and so it has been ever since the first stratum of
limestone was formed out of the remains of the animals and plants of the
sea. The rate of the accumulation of stalagmite in caverns is
necessarily variable, since it is determined by the presence of varying
currents of air. In the Ingleborough cavern a stalagmite, measured in
1839 and in 1873, is growing at the rate of .2946 in. per annum. It is
obvious, therefore, that the vast antiquity of deposits containing
remains of man underneath layers of stalagmite cannot be inferred from a
thickness of a few inches or even of a few feet.

The intimate relation which exists between caves and ravines renders it
extremely probable that many of the lat