238 LECTURE IX. 



found, which must have come from a distance, as they belong 

 to different formations from those found in the vicinity of the 

 cavern. The clay is either loose, or so penetrated with lime 

 that it forms a solid cement, which can only be split with a 

 chisel. At times there are found angular stones, mostly de- 

 tached fragments from the walls of the cavern. The deposit 

 of this ossiferous clay is frequently very thin, but in some 

 cases so abundant, that it is stated that in the grotto of Ban- 

 well in England, one chamber fifteen meters high is nearly 

 filled with this ossiferous mud. 



We are, in fact, perfectly justified in designating this cave 

 clay, mostly of a reddish tinge, which is only reached by 

 piercing through the hard stalactite deposit, as osseous clayj 

 for in it we find frequently a considerable quantity of bones. 

 Besides these bones, to which we shall presently advert, we 

 meet in the clay land and freshwater snails, which belong to 

 sjjecies still existing in the same spot. 



The bones lie in this clay pell-mell, without any trace of 

 order. The skulls are usually separated from the lower jaws, 

 the other bones of the skeleton lie scattered about. Skeletons 

 complete in the relative positions of the parts have probably 

 never been found ; even such a discovery as that made in the 

 cave of Brixham, where all the bones of the posterior leg of a 

 bear were found in their proper position, is a rare exception. 

 It seems, however, that in most cases the bones had been in- 

 troduced into the caves more or less with the flesh attached, as 

 most of them have preserved their sharp angles and margins ; 

 others, however, have manifestly been transported and rounded, 

 whilst others, again, are split up, just as if they had, previous to 

 their introduction, been long exposed to the action of the 

 atmosphere. In many caverns, bones have been found evi- 

 dently gnawed or cracked, while some presented manifest 

 traces of having been worked by man. 



The preservation of bones gives no clue to their age. 

 Where the stalactite roof is wanting, and the mud remained 

 dry, the bones are so decayed that they crumble into dust on 

 being touched. Where there is a stalagmite floor, they are in 

 a better state of preservation, and have even conserved the 



