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Proceedings of the Eoyal Society of Edinburgh. [Sess. 
6. The gravel on the floor of the cave is composed of well-rounded 
stones, comprising quartzites, porphyrites, serpulite-grit, fucoid-beds, and 
limestones. Most of the materials are foreign to the cave. They might 
have been obtained by streams traversing the quartzite slopes of Breabag 
and the drift-covered limestone plateau. The arrangement of the layers 
and the interlocking of the pebbles indicate that the gravel was deposited 
by a stream issuing from the cave. It is evident, therefore, that the stream 
transporting these stones from the upper part of the catchment basin of 
Allt nan Uamh must have flowed underground on reaching the limestone 
plateau, and that part of the current at least must have found a channel 
through the bone-cave. It is quite possible that this gravelly bed may 
S. "■ 
Fig. 6. — Diagrammatic section showing sequence of deposits in Creag nan Uamh Bone-Cave. 
1, peaty layer; 2, marl ; 3, cave-earth ; 4, grey clay ; 5, bed of limestone fragments ; 6, gravel. 
have accumulated on the floor of the cave while glaciers still existed in the 
high ground to the east. 
5. The bed of fine splinters of limestone overlying the gravel indicates 
that the cave had already become a dry one, and that the water had begun 
to circulate at a lower level. The limestone fragments appear to be largely 
due to frost action on the roof and sides of the cavern. The almost entire 
absence of red clay or terra rossa would seem to indicate that there was 
very little drip from the roof during the accumulation of this bed. 
From this layer were exhumed the remains of the Arctic Lemming, 
Field Vole ( Microtus agrestis), Rat Vole ( Microtus ratticeps), Bear, and 
birds. The great number of pinion bones and anchylosed dorsal vertebral 
bones of birds shows that the deposit must have been formed very slowly. 
The pinion bones of ptarmigan occur in lenticular layers containing the 
remains of hundreds of individuals. 
