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stalagmite, and the clue which we may have as to those circumstances in any 
particular case is often so indistinct and broken, that we cannot follow its 
indications with any confidence. We know that beds of a tufaceous character, 
such, for instance, as the upper so-called stalagmite of Kent’s Hole, may 
attain many feet in thickness in a very small number of years. 
The most weighty evidence as yet before us of a probably high antiquity 
for man in North-Western Europe appears to be that derived from the alter- 
ations in physical geography which seem to have taken place since his advent ; 
such evidence is derived from the present height of certain terraces containing 
his works far above the level of existing rivers. Such alterations would 
appear to have taken place in the case of the Thames, the Clyde, the Somme, 
the Seine, and other streams. In some of the instances given, however, the 
river-banks bordered estuaries, and were probably affected by the tides, in 
which case we need not look to the slow accumulation by ordinary fiuviatile 
depositions of sediment; and it is possible that where estuarine terraces 
occur, both the higher and the lower terrace may have been contem- 
poraneously formed, since a high-tide and a low-tide terrace are a common 
occurrence on our coasts, and the subsequent elevation of the land would 
account for the present position of the terraces above the level of the river. 
Such elevation appears to have occasionally been far from slow. Canoes, 
which seem to have been constructed with metallic tools, have been found 
25 feet above the present high-water mark on the banks of the Clyde ; and it 
is a well-known fact that the alteration of some of our coasts has been both 
great and rapid during the historical period. We have no certain clue as to 
the rate of changes of elevation in the Pleistocene age. Evidence drawn 
from inland valleys may require more careful examination, as the cutting 
power of rivers varies greatly in different districts according to the volume 
and rapidity of the stream, and also the nature of the rocks passed over; and 
in times when the country was more densely wooded, the rainfall may have 
been far in excess of the present average. That the accumulation of bones 
of the extinct mammalia found in conjunction with human remains in caves 
cannot all be assigned to the work of a flood is very clear to any one who has 
taken part in the exploration of such caves. I will refer only to those with 
which I am best acquainted, viz., the caves of Cresswell; these are, it may be 
observed, not more than 15 ft. above the present level of the stream. The 
bones found in them, with but few exceptions, bear no evidence of having 
been rolled along by a current of water, but, on the contrary, appear to have 
been left where they are now found, iu many cases, by the hyaenas, which 
devoured the carcasses of the animals; the fractured edges are frequently seen 
to be as sharp as if done quite recently ; this could not have been the case 
had they been subjected to rolling in water for even a very short period. 
Other evidence of their being the slow accumulations of many years in the 
spot where they are now found is seen in the character of the beds in which 
they occur. The floors of the caves are not of one uniform nature, but are 
distinctly stratified, and contain remains to a certain extent peculiar to each. 
2 B 2 
