210 C. Damson — Mountain Evolution. 



Kashmir, according to Drew and Lydekker (Mera. Geol. Surv. Ind. 

 vol. xxii. p. 32), the case is very similar. In short, so far as I can 

 see, the extension of the glaciers in the Himalayas was very similar 

 to what it was in the Alps ; but as the latter are from 15° to 20° 

 farther north, the glaciers came to the base of the mountains, and 

 flowed over some of the adjacent country, whilst in the Himalayas 

 all the ice melted within the range. 



The only other fact cited by Mr. Howorth is the curious occur- 

 rence of remains of fossil Horses, Bovines, Ehinoceroses, etc., in 

 Hundes. Here, too, I think be has ovei-looked part of the evidence, 

 as he evidently is under the impression that none of the animals 

 mentioned, Horse, Ox, Deer, Ehinoceros, and Elephant, can live at 

 such elevations as 15,000 feet. The fact is, however, as Mr. 

 Lydekker has shown, that wild horses [Equus Jiemionus) and. Oxen 

 (or rather Yaks, Bos grunniens) do inhabit Hundes at the present 

 day, that the supposed Deer are Antelopes belonging to the genus 

 PantJiolops, peculiar to the Tibetan plateau, and that the only 

 difficulty is about the Ehinoceros (the occurrence of Elephas is 

 doubtful, 1 believe). The beds containing the remains are now 

 regarded by Mr. Lydekker (Eec. Geol. Surv. Ind. 1887, p. 54) as 

 Pliocene, not Pleistocene. It is probable that these beds have under- 

 gone a certain amount of elevation ; but if I were obliged to decide 

 which is more improbable, that a Ehinoceros in Pliocene times 

 lived 15,000 feet above the sea, or that the Tibetan plateau has 

 been raised to that elevation from near the sea-level since the 

 Pliocene period, I should feel very little difficulty in coming to 

 a conclusion. 



I am not prepared to accept all Mr. J. F. Campbell's views as to 

 the Himalayas, but there is one remark in his paper with which 

 I thoroughly agree. He infers from the circumstance that what he 

 calls the " waterfall zone " lies close to the sources of the rivers, 

 that the watercourses in the Himalayas are very old. I think if 

 Mr. Howorth had had an opportunity of seeing what is perhaps the 

 grandest example of subaerial denudation in the world, he would be 

 as little inclined as I am to believe that such gigantic furrows as 

 the Himalayan valleys can have been ploughed out by rain and 

 rivers since the frozen Mammoths were imbedded in the gravels of 

 the Siberian tundras. 



Y. — Note on the Expansion Theory of Mountain-Evolution. 



By Chaeles Datison, M.A. ; 

 Mathematical Master at King Edward's High School, Birmingham. 



IlHFi following is the fundamental principle of the theory of 

 terrestrial evolution which has been sometimes called the 

 " expansion theory " : — 



Masses of sediment laid down in an area of subsidence are 

 gradually lowered to regions of the earth's crust that are at a higher 

 temperature than that in which they were deposited. The sediment, 

 being heated, expands, is crumpled and folded internally, and, 



