The Scottish Naturalist. 103 



and that, from a geological point of view, not very remote, when 

 the greater part of the country was covered by an immense ice- 

 sheet. During that period there was probably no vegetation in 

 any part of these islands, and hence we may be sure that there 

 were no Lepidoptera. This state of matters had existed for 

 many ages before the time I speak of, but not with uninterrupted 

 severity. Warm periods occasionally occurred, when the icy 

 shroud of the country was removed, and the land was clothed 

 with vegetation, varying in its nature according to the character 

 of the climate. Sometimes the plants belonged — as may be 

 learnt from the vegetable remains still preserved in the east of 

 England and elsewhere — to the alpine and arctic groups, in- 

 cluding such species as Betula nana and Salix polaris ; and we 

 may be pretty certain that Lepidopterous larv^ were there to 

 feed on the leaves. It is true that Lepidoptera have not, I think^ 

 been found in association with the plant remains, nor, from their 

 fragile and perishable character, could we well expect them to 

 be ; but the remains of Coleoptera, both herbivorous and carni- 

 vorous, have been found, and it is not likely that other insects 

 were absent. Therefore, though we cannot prove it, it seems 

 very probable that some of the species treated of in this paper 

 were then inhabitants of Britain. But, as I have already said, 

 arctic conditions returned and destroyed all the plants and 

 animals, and those whose descendants we see at the present day 

 must have had a more recent introduction. 



Two views have been advanced as to the condition of this 

 country during the final stage of the icy or glacial period. The 

 older view was, that most of the country was submerged, and that 

 only the hills remained above water. To these islandrhills icebergs 

 drifted, and deposited their burdens of stones, earth, and other 

 debris^ including seeds of the various arctic-alpine species, which 

 now form part of the flora of many of the high hills. Admitting 

 that the same vehicles might have brought the mountain Lepi- 

 doptera, and that they were able to survive the dashing to and 

 fro, the intense and prolonged cold, and the probable submer- 

 gence in salt water, and that, moreover, there were localities 

 whence it was at all likely that they could be brought, the proofs 

 are wanting that such a condition of the country existed, while 

 many incontestable proofs have been advanced in favour of the 

 other and more modern view, set forth so admirably by Dr James 

 Geikie in his * Great Ice Age,' to which work I refer those desir- 

 ous of examining into it for themselves. 



