PLEISTOCENE CAVE-DEPOSITS. 73 



older date than the Pleistocene Period — that is to say, the time 

 when Europe was tenanted by Palaeolithic man and the old 

 mammalia. We cannot doubt that those caves were in existence 

 in the preceding Pliocene Age, and that many (perhaps most) 

 were as open to the day then as in early Palaeolithic times. 

 Yet if this were so, why is it that they do not contain abundant 

 remains of the old Pliocene mammalia, or even of the animals 

 that were characteristic of the still earlier Miocene Period? 

 Professor Boyd Dawkins has suggested that the caves which 

 were accessible in Miocene and Pliocene times may have been 

 destroyed by the agents of erosion before the beginning of the 

 Pleistocene Period, and certainly the thickness of rock, which 

 has been peeled off the face of the country and carried in the 

 form of gravel, sand, and mud into the sea since the close of the 

 Miocene Period, is so enormous that there may well be much 

 truth in Mr. Dawkins's suggestion. Indeed, as regards any bone- 

 caves of Miocene age, it may be strongly doubted whether they 

 could possibly have existed down even to Newer Pliocene 

 times ; for the denudation which can be shown to have taken 

 place before the beginning of the Pleistocene Period would more 

 than suffice to account for the total disappearance of many 

 extensive caves, carved out of much more durable rocks than 

 limestone. But I do not think that Mr. Dawkins's hypothesis 

 accounts equally well for the total absence from our caves of 

 Pliocene bone -accumulations. The Pliocene Period was not 

 separated by any prolonged interval from the succeeding 

 Pleistocene Age. Quite the contrary, as we know, was the case, 

 for some of the mammals of the former period lived on into the 

 latter, and their remains are found commingled with those of 

 typical Pleistocene species in the floor-deposits of the caverns. 

 Although we admit as a possibility that the caves which were 

 accessible in early Pliocene times may have disappeared prior to 

 the advent of the great body of the Pleistocene fauna, yet we 

 find it hard to believe that the same could have been the case 

 with all the caves which may have been visited by the Pliocene 

 mammals during the later stages of that period. It would be 



