16 DE. H. HICKS OK SOME 



seem to me, from a study of the deposits, to be some of the changes 

 indicated. The lowest deposits in the caverns, consisting almost 

 entirely of local materials, must have been introduced by a river 

 which flowed in the valley at a very much higher level than does 

 the little stream at present. As the valley was being excavated, 

 and the caverns were above the reach of floods, Hysenas and other 

 beasts of prey occupied them, and conveyed the remains of other 

 animals into them. Man also must have been present at some part 

 of this period. Gradually the land became depressed, and the 

 animals disappeared, stalagmite was formed in the caverns, and the 

 sea at last entered them, filling them up with sands and pebbles, 

 and burying also the remains not washed out. Pleating ice deposited 

 in this sea the fragments of rocks derived from northern sources, 

 and these became mixed with local rocks and clays brought down 

 from surrounding areas. The greater part of the Boulder-clay in 

 the Yale of Clwyd was probably deposited as the land was being 

 raised out of this Mid-Glacial sea. During the process of elevation 

 the caverns became again disturbed by marine action, and the uj^per 

 fine reddish loam and the laminated clays were deposited. The 

 following stages may in that manner be accounted for, and I know 

 of no other influences which ofi'er better means for their interpreta- 

 tion : A. The infilling of the caverns by local gravels. B. The 

 occupation of the caverns by beasts of prey and by man. C. The 

 formation of the stalagmite. D. The breaking up of the stalagmite 

 and the introduction of the marine sands and pebbles. E. The 

 deposition of the laminated clay, and of the reddish loam. It seems 

 to me impossible to avoid the conclusion that these caverns must 

 have been submerged and afterwards elevated to their present 

 height of about 400 feet above the level of the sea, since they were 

 occupied by Palaeolithic man and the Pleistocene animals. 



KoTE (Dec. 19th). — In arriving at the foregoing conclusions I 

 endeavoured to weigh carefully all evidence tending in any way 

 towards showing the possibility that the materials in the caverns 

 might have been introduced by streams in Post-Glacial times. The 

 evidence, however, seemed to me so much stronger in favour of sub- 

 mergence that I felt compelled to assign the effects to that cause 

 rather than to influxes of water either from the valley or the land 

 above. It must be granted by all that at the close of the so-called 

 Glacial Epoch, or, it may be said, of the last great submergence, the 

 ravine must have been filled up by Boulder-clay to above the level of 

 the caverns, and that the caverns must have iDeen in existence 

 before the clay was deposited. What changes, therefore, would be 

 necessary to produce the effects observed if the occupation of the 

 caverns by the Hyaenas was subsequent to the deposition of the 

 Upper Boulder- clay ? .The upper cavern would have to be un- 

 covered at a much earlier period than the lower. An ex avation 

 of 22 feet would then have to be made before the lower one 

 would be exposed, in a valley over 500 feet wide at that point, by a 

 stream draining but a very limited area, the highest land drained 

 by it being only about 800 feet above sea-level. Each cavern would 



