ioo THE SCOTTISH NATURALIST 



whose presence is indicated by a single canine tooth, is also 

 extinct in Scotland, although it survived even down to early 

 historic times. 



The assemblage of birds from the lower deposit shows 

 little to distinguish it from that of to-day ; it contained a con- 

 siderable variety of ducks Teal, Widgeon, Tufted, Long- 

 tailed, and Eider Duck, as well as the Common Scoter, the 

 Grey Plover, the Little Auk, the Red Grouse, and the 

 Ptarmigan, and perhaps the Chaffinch. But again there is 

 a distinct hint of conditions different from those of the 

 present, and much more arctic in character ; for at this 

 comparatively low altitude, about iooo feet above sea-level, 

 Ptarmigan were evidently far more abundant than Grouse ; 

 indeed, in the slowly formed deposit the pinion bones of 

 Ptarmigan were found to occur in lenticular layers con- 

 taining the remains of hundreds of individuals. 



It is worth noting, also, that the assemblage of birds, 

 though containing no species of outstanding mark, is a 

 curious one to have been found in such a place, distant, as 

 the crow flies, more than a dozen miles from the sea ; for 

 a very large proportion consists of distinctively marine birds 

 Diving Ducks, the Puffin, and the Little Auk. It is true 

 that the last often wanders a considerable distance inland, 

 but the Puffin is a coastal bird, and neither it, nor, to mention 

 another example, the Eider, ever move far from the shore. 

 But the physical conditions of the latter period of the Ice 

 Age help to explain this inland occurrence of shore birds, 

 since during some indefinite period after the time of 

 maximum glaciation the sea rose relative to the land at least 

 ioo feet, at which level the ioo-foot beach characteristically 

 developed on the west coast was formed. Such an alteration 

 of level must have had a considerable influence upon the 

 Loch Assynt area, which contains a fair proportion of low 

 ground merging on the sea. It is possible that the glacial 

 action of the maximum glaciation had scoured the bottom of 

 the Inver valley to so low a level that the ioo-foot sea 

 approached near to, if it did not enter, Loch Assynt. Such 

 conditions would bring the sea margin within reasonable 

 distance of the Bone Cave, and would account for the fact 



