Sir S. H. Hoicorth — Erratic Boulders in Drift. 125 



obtuse one, or be marked by bummoclcs, tbe strain upon tbe ice at 

 certain points will cause it to crack and gape and to form crevasses. 

 These crevasses will remain open so lonoj as tbe strain exists, but 

 when the glacier gets on to even ground they will necessarily close 

 lip again. We cannot understand how crevasses can be formed, or 

 remain open long, where ice is moving over a level or nearly level 

 surface. 



The result of tbe formation of these crevasses if tbe ice be not 

 very tbick is that some of the stones wbicb have fallen on the 

 glacier's back will tumble down fissures and reach the glacier's 

 bed. The rest wliicb escape this and similar catastropbt^s 

 will continue their journey, as before, to tbe glacier's foot. This 

 process has been often observed, and is, of coui^se, an elementary 

 experience in the Alps. It is usually argued by those who believe 

 in ice-sheets several miles high that exactl}' the same process would 

 take place with them. How this is to be brought about I fail to see. 

 A great hummock or lump in a glacier's bed may cause a sufficient 

 strain to crack and open out a crevasse in ice two or three hundred 

 yards tbick ; but what possible lump or hummock is to cause sufficient 

 tension in a mass of ice even a mile thick so as to cause it to crack 

 and gape, is beyond my prosaic mind to conceive. This stupendous 

 mechanical difficulty is not met at all by the Glacialists, but is quite 

 ignored by them. 



The fact is, that even in the Alps, where the ice is tbick, a gi'eat 

 many of tbe crevasses do not reach the bottom of tbe glaciers at all, 

 and the stones which fall into them are arrested midway, foi'ming 

 tbe so-called englacial boulders about wbicb so much astonishing 

 matter has been written, and to which I shall revert presentlj'. 

 What I now wish to emphasize is, that where no rocks project above 

 the surface of the ice the glacier will carry no stones. This is 

 beautifully proved by tbe case of Greenland. In those parts of 

 Greenland where there are no NimataJckar, the Danish observers 

 have noticed that there are no moraines, and it would seem to follow 

 that when, as is postulated by the extreme Glacialists, the whole of 

 a country was buried deep in ice and there were no projecting rocks 

 above its surface, there could be no boulders on its back. 



I cannot conceive bow it is possible to understand (as a mere 

 piece of mechanics) how crevasses could be formed at all in those 

 stupendous ice-sheets which are continually postulated, and bow, 

 tbei'efore, any stones could under any circumstances reach the 

 ice-back or tbe ice-bed in such cases. The ice-sheets would be as 

 barren of stones as the glaciers of Central Greenland are of moraines. 

 Let that pass, however. 



Following in the footsteps of my friend, Mr. Oldham, I have tried 

 to show in my " Glacial Nightmare " that ice cannot be moved 

 en masse along a level surface by any push from behind it for more 

 than about seven miles without crushing, and in order to move it in 

 this way tbe thrust must be enormous when tbe ice is at all thick — 

 so enormous that I have never been able to understand how and by 

 vphat process the thrust can be transmitted along the mass when 



