DE RANGE : THE VALE OF CLWYD CAVES. 
19 
alluded to, cutting off its upward or vertical prolongation. The sand 
band now described is about o inches in thickness, and ranges horizon- 
tally when in contact with the north joint, but dips westwards along 
the northern face of the pit up to the next bank, where in common 
with the other beds at the lower part of the section, it dips south- 
wards. Between this sand bed and the "tumbler" is a bed of red 
clay 6 inches thick. So far as I could ascertain this clay passes down 
behind the " tumbler," but we considered it dangerous to remove it 
and ascertain, as the whole bank might have been brought down on 
our heads. 
The red clay up to a certain height contained bone fragments, 
and the teeth of a hyaena from the north, or clay joint up to and over 
the "tumbler" fragments of stalagmite were numerous, but I saw none 
above 2 inches in length, I observed no fragments of stalagmite or 
bones in the red clay above the laminated sand-bed. The sand pipe 
adjacent to the " tumbler " appears to owe its origin to percolation 
of water in the 5-inch sand-bed, which has carried the sand, filling 
up the fissure between the side of the block and the adjacent red 
clays, these latter are obviously the flow which arrests and throws 
out the spring at the north, or "clay joint," which has been 
similarly filled by the passage of water carrying Boulder Clay from 
above. The "saturation plane" in the rock beneath, I found by obser- 
vations in the Fynnon Beuno Cave in 1885, to be but slightly above 
the stream level, the dryness of the tunnel-cave is due to the cap of 
Boulder Clay which overlies the hill, but the clay is not wholly 
impermeable, water traversing joints in it, to which process is probably 
due the infilling of the north joint with clay, as described. 
I undermined the western bank of the Cae Gwyn pit for about 
2 feet, the red bone-earth continued as far as we went, containing 
fragments of stalagmite and bone, there is no evidence to show how far 
westwards this deposit extends, traces of bone occurred at a point 
5 feet from the overhanging ridge of the cave, and I think it a matter 
of great regret if the extent of its western prolongation be not settled. 
From the facts observed during the past half century, it would 
appear that the following conclusions may be considered definitely 
settled. 
