84 
weather, although at present certainly all water that drops 
from the roof seems to be well filtered. In the Lower Cave- 
Earth, between the blocks of limestone, little chinks have 
been filled in with laminated clay,* which is possibly of the 
same age, and deposited under identical circumstances, with 
the great mass of it above — the conditions necessary for this 
only being a pre-existing chink and a crack leading to it, 
wide enough to permit water to trickle through it, bearing 
the finest impalpable mud. Both these beds. Upper and 
Lower, contain the remains of man and animals scattered 
along more or less definite horizons to be further described. 
The Laminated Clay. — This lies between the beds already 
described, and the great contrast which it shows to them 
induced me in 1870 to study it more particularly with a view 
to getting some insight into the conditions under which it 
was formed. The laminae into which it is divided are ex- 
ceedingly thin, and flake away easily when pulled asunder, 
yet it is so stiJBP as to make the digging of it a work of great 
labour. It is found to consist of an exceedingly fine impalp- 
able mud. About 8 per cent, of it is carbonate of lime. It 
varies in thickness, but has been found in all the chambers 
hitherto explored. In the left hand Chamber B, it showed a 
thickness of 12 feet, in other parts 7 and 8 feet have not 
been uncommon dimensions. It was thin at the entrance, 
thickened rapidly and thinned again, but it has been found 
to run continuously from the entrance inwards, a distance of 
more than 70 feet, which is as far as the explorations have 
gone along that horizon in the right hand Chamber (D) . In 
casting about for an explanation of the singular contrast of 
this bed to those above and below it, I was unable to resist 
the conclusion that different physical conditions were neces- 
sary for its formation. Similar clays are found intercalated 
* See foot note, p. 85. 
