138 QUANTITY OF BLACK ANIMAL EARTH. 
which are nearly equal to those of the interior of a large church) there 
are hundreds of cart-loads of black animal dust entirely covering the 
whole floor, to a depth which must average at least six feet, and which, 
if we multiply this depth by the length and breadth of the cavern, will 
be found to exceed 5000 cubic feet. The whole of this mass has been 
again and again dug over in search of teeth and bones, which it still 
contains abundantly, though in broken fragments. The state of these 
is very different from that of the bones we find in any of the other 
caverns, being of a black, or more properly speaking, dark umber colour 
throughout, like the bones of mummies, and many of them readily 
crumbling under the finger into a soft dark powder resembling 
mummy powder, and being of the same nature with the black earth 
in which they are embedded. The quantity of animal matter accu¬ 
mulated on this floor is the most surprising, and the only thing of 
the kind I ever witnessed; and many hundred, I may say thousand, 
individuals must have contributed their remains to make up this 
appalling mass of the dust of death. It seems in great part to be 
derived from comminuted and pulverised bone; for the fleshy parts 
of animal bodies produce by their decomposition so small a quantity 
of permanent earthy residuum, that we must seek for the origin of 
this mass principally in decayed bones. The cave is so dry, that the 
black earth lies in the state of loose powder, and rises in dust under 
the feet; it also retains so large a proportion of its original animal 
matter, that it is occasionally used by the peasants as an enriching 
manure for the adjacent meadows*. 
* I have stated, that the total quantity of animal matter that lies within this cavern 
cannot be computed at less than 5000 cubic feet; now allowing two cubic feet of dust 
