DBIETS OP THE VALE OF CLWTD. 



109 



proved to have sealed up a cave containing the remains found in the 

 Ffynnon Beuno caves, 



But as a question of evidence, we must remark in passing that 

 the flake and bones outside the cave occurred just where the swallow- 

 hole must have descended which fed the upper entrance to the upper 

 cave before it was quite choked up. 



The real point of interest is this : — the north-west end of the cave 

 was blocked by drift, and what appeared to be part of the ossiferous 

 cave-deposit extended over the ledge outside the cave and was 

 covered by the drift. What drift was this ? 



Referring to the table of the drifts, p. 73, 1 first explain that it 

 cannot be the Arenig Drift, because it contains flint and north- 

 country boulders. It cannot be earlier than the St. Asaph Drift, 

 which is marine-postglacial, and contains no scratched stones except 

 those derived from the preexisting boulder-clay. 



This settles the first and most important question. Even if the 

 cave were sealed by the St. Asaph Drift, the deposits in it would not 

 be preglacial. 



But can it be the undisturbed marine St. Asaph Drift ? I think 

 not. I have shown that the marginal deposits of that age, where 

 they can be observed, are sands and gravels, such as we might expect 

 upon a rocky shore, and such as we see now being formed along the 

 North AYales coast — such as are seen up the very same ravine near 

 the limestone rock between T Graig and Cae Gwyn. 



The deposit outside the Cae Gwyn cave consists of fine sand with 

 earthy patches and scattered boulders, of such a character and 

 arranged in such a manner as would result from the working down 

 the slope of surface-debris from the drift. 



The cave-deposits of Plas Heaton or Cae Gwyn cannot belong to 

 the period of submergence ; for there is no great upsloping bank of 

 shingle, such as may be seen in any cave reached by the tide ; nor 

 would such a sea-cave have been the haunt of man or of the 

 hyaena. 



It is quite impossible that whether during the occupation of the 

 cave, or during a later submergence,, the lashing waves on a rock- 

 bound shore exposed to the north-west winds should not have swept 

 away all loose debris into the fjord below. 



That is probably why we have not yet, and possibly may not in 

 any such situation, find the cave-deposits of the age just before the 

 submergence. Such a cave as Cae Gwyn would have been swilled out, 

 and the ledges in front of and around it swept quite clean by every 

 tide, and the washed-out drift would have settled down in the 

 depths below, beyond the reach of the wind-waves and shore- 

 currents. 



If, then, the cave-deposits cannot have been formed before the 

 submergence, because rocks first brought into the district during 

 the submergence are found in the drift at the mouth of the cave, 

 and debris from this drift is found in the cave, and if further, from 

 the character and distribution of the cave-deposits, they cannot be 

 due to marine action during the submergence, it follows that they 



