44 ESKAR EXCAVATION' IX NOVA SCOTIA. PREST. 



show that the river once ran at this high level. To do so it 

 must have occupied a glacial crevasse until the ice melted 

 enough to allow it to occupy its original bed. We may 

 reasonably conclude that during this time all the material 

 that would otherwise have been transported in lower channels 

 filled the crevasse. 



The same enormous valley eskars are seen in the basin of 

 Enormous the Ashuanippi and other rivers of Labrador. 

 eskars nf Details concerning these eskars have been pub- 

 Labrador y^^^ied by the Canadian Geological Survey. 



A friend has drawn my attention to the frontal theory of 

 eskar formation advanced by W.B.Wright, of the Geological 

 Survey of Iceland. In this the essential condi- 

 ^^^ tion is the presence of stagnant water along a 



tJieory retreating ice front. In reply I must say that 

 such a condition could not apply on this gradually 

 sloping watershed where the wide river valley offers no obstruc- 

 tions capable of forming anything larger than pools and ponds. 

 These long ridges of variously bedded deposits of varied 

 character means locally confined and swirling currents and 

 changing conditions of very local extent. Only on the low 

 lands where lakes are possible is the debris from the eskar 

 spread out in wide banks of regular stratified material. 



Trowbridge, writing on the eskars of the west, notes that 

 eskars are more common on rough than on level country. 

 For instance, hundreds are seen in Maine and 

 Evidence Sweden, while on the Upper Mississippi they are 

 ]Vesi^ very rare. This is valuable evidence, and indi- 

 cates the need of inequalities of surface for the 

 production of the tension needed for the formation of crevasses. 



Finally, I will put this problem to opposers of the crevasse 



theory of eskar formation: How could the quiet water 



necessary for fine clay deposition on the top of an 



^" eskar, and on the slope of a watershed, ever have 



^robkm been retained except by enclosing walls that 



have since disappeared? 



In my former paper on Eskars read before this Institute 

 Former in 1918, I maintained the crevasse theory of 

 paper the origin of eskars. I still see no reason to 

 on eskars ^^j^^j, ^y conclusions. 



