THE ESKERS OF NOVA SCOTIA. PREST. 385 



13. Eskers in river valleys only show strong evidence 

 of having become lines of drainage, until the total disappear- 

 ance of the ice allowed the streams to follow their present 

 course. 



A Rare Phenomenon. — Most investigators have made 

 the usual mistake of ascribing uncommon results such as 

 eskers, to the most ordinary causes. Thej^ must necessarily 

 be ascribed to uncommon causes, because of their striking 

 difference from every other class of deposit. 



Glacial Crevasses.-^A perusal of the explorations of 

 Peary and Nansen on the Greenland ice and Shackleton, 

 Scott and Amundsen across the Antarctic continent shows 

 that one of the most striking features of these ice-covered 

 lands are the long deep transverse crevasses that obstructed 

 their way. Nansen says that these crevasses were largest 

 and most numerous in Greenland where the central plateau 

 breaks off into slopes 7 or 8 miles from the east coast and 25 

 miles from the west coast. Nansen and Peary saw some 

 crevasses 50 feet wide and on the Antarctic continent they 

 were even wider. Nordenskjold also adds his testimony 

 to this. So deep were some of these crevasses that they could 

 not be sounded. So long were they that the ends were 

 seldom seen. Shackleton mentions several from 10 to nearly 

 100 feet wide and mentions some down which he could 

 see 300 feet. In others no bottom could be seen. Many 

 of these great crevasses broke up into smaller ones which 

 spread out and finally became untraceable. At least one 

 of the long eskers of Maine exhibits this peculiarity. These 

 deep snow-covered crevasses were veritable death traps. 

 One black and apparently bottomless crevasse holds the 

 last of Shackleton's ponies; others hold the bodies of many 

 adventurous explorers, entombed in a sepulchre of ice. At 

 another place was a belt of crevasses half a mile wide. This 

 is probably a repetition of the tributarj' and delta sj'stems 



