Bone Caves. 461 



wearing out of the caves has been going on for unknown 

 periods of time, and some of them may have been filled 

 with sediments, perhaps charged with bones, again and 

 again. There is often proof that, by underground 

 changes of waterflow, old consolidated gravels that filled 

 them to the roof have been, at various periods, forcibly 

 cleared out by natural means. When, therefore, we find 

 bones in these caverns, mixed with red loam, sand, 

 gravels, and angular fragments of rock, it is very diffi- 

 cult, and perhaps sometimes impossible, to define to 

 what precise 'minor period they belong ; for, viewed on 

 a large scale, all periods from later Miocene times 

 downwards are minor periods. 



In such caves the bones of extinct mammals, probably 

 of pre-Grlacial, and certainly sometimes of Glacial times, 

 are found, together with the remains of species that still 

 inhabit our country and the Continent of Europe ; and 

 as it is hard to separate them, I must devote these 

 paragraphs to caves in general. 



Sometimes the skeletons, or parts of them, seem to 

 have found their way in through the mouths of the 

 caverns ; more frequently they were washed in through 

 ' pot-holes ' and openings in their roofs. On the verge 

 of the mouths of large bell-shaped pot-holes, on the 

 Carboniferous Limestone plateaux of Yorkshire, under 

 which we hear the water rushing, I have often seen the 

 carcases, or detached bones, of sheep waiting for a 

 flood to be carried below. 



Sometimes the detached bones of animals, or the 

 animals themselves, have been dragged in by beasts 

 of prey, such as Bears and Hyaenas, that inhabited 

 these caves. One evidence of this is, that the bones 

 are frequently gnawed, and still bear the marks of the 

 teeth of carnivora, as first shown by Dr. Buckland ; and 



