VOL. LXXXIV.] PHILOSOPHICAL TRANSACTIONS. 441 



scription are found in very different situations, which makes their present state 

 more difficultly accounted for. Those in Germany are found in caves. The 

 coast of Dalmatia is said to be almost wholly formed of them, and we know that 

 this is the case with a large portion of the rock of Gibraltar. 



If none were faund in caves, but in solid masses covered with marl or lime- 

 stone, it would then give the idea of their having been brought together by some 

 strange cause, as a convulsion in the earth, which threw these materials over 

 them ; but this we can hardly form an idea of; or if they had all been found in 

 caves, we should have imagined these caves were places of retreat for such ani- 

 malSj and had been so for some thousands of years; and if the bones were those 

 of carnivorous animals and herbivorous, we might have supposed that the carni- 

 vorous had brought in many animals of a smaller size which they caught for 

 food; and this, on the first view, appears to have been the case with those which 

 are the subject of this paper; yet when we consider that the bones are principally 

 of carnivorous animals, we are confined to the supposition of their being only 

 places of retreat. If they had been brought together by any convulsion of the 

 earth, they would have been mixed with the surrounding materials of the moun- 

 tains, which does not appear to be the case; for though some are found sticking 

 in the sides of the caves incrusted in calcareous matter, this seems to have arisen 

 from their situation in the cave. Such accumulation would have made them co- 

 eval with the mountains themselves, which from the recent state of the bones I 

 should very much doubt. 



The difference in the state of the bones shows that there was probably a suc- 

 cession of them for a vast series of years; for if we consider the distance of time 

 between the most perfect having been deposited, which we must suppose were 

 the last, and the present time, we must consider it to be many thousand years; 

 and if we calculate how long these must still remain to be as far decayed as some 

 others are, it will require many thousand years, a sufficient time for a vast accu- 

 mulation: from this mode of reasoning- therefore, it would appear that they were 

 not brought here at once in a recent state. 



The animal earth, as it is called, at the bottom of these caves, is supposed to 

 be produced by the rotting of the flesh, which is supposing the animals brought 

 there with the flesh on; but I do conceive, that if the caves had been stuffed 

 with whole animals, the flesh could not have produced a 10th part of the earth; 

 and to account for such a quantity as appears to be the produce of animals, I 

 should suppose it the remains of the dung of animals who inhabited the caves, 

 and the contents of the bowels of those they lived on. This is easily conceived 

 from knowing that there is something similar to it, in a smaller degree, in 

 many caves in this kingdom, which are places of retreat for bats in the winter, 

 and even in the summer, as they only go abroad in the evenings; these caves 



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