63 TOWN GEOLOGY. [11. 



caused by a change in the distribution of land and 

 water, or by change in the height and size of these 

 islands, which made them large enough, and high 

 enough, to carry a sheet of eternal snow inland ; or 

 whether, finally, the age of ice was caused by an actual 

 change in the position of the whole planet with regard 

 to its orbit round the sun shifting at once the poles 

 and the tropics ; a deep question that latter, on which 

 astronomers, whose business it is, are still at work, 

 and on which, ere young folk are old, they will have 

 discovered, I expect, some startling facts. On that last 

 question, I, being no astronomer, cannot speak. But 

 I should have liked to have said somewhat on matters 

 on which I have knowledge enough, at least, to teach 

 you how much there is to be learnt. I should have 

 liked to tell the student of sea-animals how the ice- 

 age helps to explain, and is again explained by, the 

 remarkable discoveries which Dr. Carpenter and Mr. 

 Wyville Thompson have just made, in the deep-sea 

 dredgings in the North Atlantic. I should have liked 

 to tell the botanist somewhat of the pre-glacial flora 

 the plants which lived here before the ice, and lasted, 

 some of them at least, through all those ages of fearful 

 cold, and linger still on the summits of Snowdon, and 

 the highest peaks of Cumberland and Scotland. I 

 should have liked to have told the lovers of zoology 

 about the animals which lived before the ice of the 

 mammoth, or woolly elephant ; the woolly rhinoceros, 

 the cave lion and bear, the reindeer, the musk oxen, 

 the lemmings and the marmots which inhabited Britain 

 till the ice drove them out southward, even into the 

 South of France ; and how as the ice retreated, and 

 the climate became tolerable once more, some of them 



