THE ESKERS OF NOVA SCOTIA. PREST. 379 



these great streams emptied after ascending the 400 foot 

 hills of south-western Maine, and after a flow of over 100 

 miles. No wide estuary is seen there. They simply disappear. 



Further on Stone saj's: ''Probably all the field phenomena 

 may be accounted for by cither hypothesis, but by such 

 cumbrous complications that in the end must break down 

 any hypothesis". Of extremely narrow eskers changing 

 to wide, high eskers, he says: "That rivers capable of trans- 

 porting so great a quantity of sediment should occupy such 

 narrow channels is truly wonderful". To this we all agree. 



Deflections. — Regarding deflections in the course of eskers, 

 many supporters of the subglacial theory cannot account 

 for their leaving a valley to cross a watershed or to cross 

 the course of the ice movement. Other deflections on level 

 plains without anj^ streams or obstacles to cause the deflection, 

 are just as unaccountable when ascribed to the subglacial 

 theory. 



After considering a great many varied theories of o'rigin, 

 we read on page 423: "The long meanderings transverse to 

 the ice-flow certainly add some difficulties to the hypothesis 

 of subglacial streams". Under the subglacial or superglacial 

 theory the following is unexplainable: At Leighton Brook, 

 a few miles south-east of Aurora, Maine, is seen a ridge of 

 boulders parallel with the ice flow. Across this at right angles 

 is a well defined esker ridge — neither interferes with the other. 

 Here we possibly have a subglacial stream crossing an esker 

 without disturbance but the foimation of the esker must 

 have been due to some other cause. 



Confusion of Theories. — The uncertainties attending these 

 theories are well shown in page 430, where we read: "No 

 positive inferences can as yet be drawn from the observed 

 facts bearing on the question of subglacial versus superglacial 

 streams, though probabilities favor superglacial streams." 

 Page 323 gives us the following: "The general inference is 

 that the courses of the great glacial rivers were determined 



