178 CAVES AND CAVE DEPOSITS. 
in rainwash. So we may suppose that if there had been shells 
in that part of the drift, they must have perished altogether, 
leaving no trace. The surface of the solid rock over and round 
the mouth of the cave was similarly weathered, and the deep 
undercut ledges are such as are commonly found along all cliffs 
of the mountain-limestone where exposed to chemical and 
ordinary subaérial weathering, and not rounded off by the 
breakers or by ice action. There was no trace of smoothing by 
ice from the north, or from any other quarter. On the whole, 
the conclusion seems to be that there were no cave deposits of 
pre-glacial age yet found in the Vale of Clwyd; that there were 
none earlier than the great post-glacial submergence ; that the 
group of animals found in the Ffynon Beuno caves were, so far, 
found only in deposits laid down after the land had begun to 
rise again, but at what stage of the emergence there was not as 
yet sufficient evidence to show; that the points upon which 
evidence was most required were the age and fossil contents of 
the Talargoch gravels, which there are reasons for suspecting 
were much later than the main mass of the Clwydian drift. 
SUPPLEMENT. 
Since this paper was read further excavations have been made 
and more evidence has been obtained, all of which fully con- 
firms the views above stated, viz., that the deposits in the cave 
are post-glacial—that the deposit which was looped down over 
the most northern explored part of the cave, and filled the only 
opening through which a man or hyena could have crept in at 
this end, was rainwash, or resorted from the Clwydian drift ; 
that the appearance of the true Clwydian drift resting on cave 
deposits was deceptive, being due to the breaking down of a 
portion of the side of the cave and the sinking in of the lime- 
stone and of the Clwydian drift on to the cave deposits—so 
that they might as well be called pre-Carboniferous as pre- 
Clwydian on such evidence. 
I append the list of shells found in the genuine Clwydian Drift 
outside the cave, as determined by Mrs. McKenny HUGHEs, 
from which it will be seen that even had the cave been blocked 
by this drift, its contents could not, on the evidence of the 
shells, be claimed as pre-glacial. I give also a list of the 
mammalia found in the cave, determined by Mr Davis, of 
the British Museum, from which it will be obvious that there is 
nothing in the fauna to favour the idea of the cave deposits 
being of pre-glacial age. 
By permission of the Council of the Geological Society, I 
give a plan of the cave and two sections, in which the position 
and character of the break-down of the side of the cave, and 
the manner of settling down of the post-Clwydian rainwash, &c., 
may be seen. These, with a full exposition of the newer 
evidence, were published in the Quarterly Journal of the 
Geological Society for February, 1888. 
