EVIDENCE DERIVED FROM THE CIRQUES 545 



the present King Eavine cirque "must have been accompanied by the 

 depositing somewhere at or beyond the mouth of King Ravine of a great 

 terminal moraine of equal proportions. There can be only one explana- 

 tion for the absence of the local moraine . . . these valleys were ice 

 carved before and not after the great ice-sheet swept across New England, 

 and only those records of local alpine glaciers remain which the ice-sheet 

 did not obliterate" (1913(a) ; 11). In further support of this interpre- 

 tation, it is pointed out that the headwalls of cirques opening toward the 

 northwest are less precipitous and less ragged than are those of cirques 

 opening to the southeast, a contrast which should be expected if the 

 southeastward-moving continental ice-sheet impinged against the head- 

 walls of northwest-facing cirques and rubbed them down, at the same 

 time passing over or plucking blocks from the heads of those facing south- 

 east. For the same reason, G-reat Gulf, which lay athwart the path of 

 the continental glacier, has a steep northwest side-wall and a more gently 

 sloping wall on its southeast side (1913(a), 12; 1914, 461). 



It does not appear that the supposed early date for the cirques receives 

 much support from the arguments quoted above. It is the writer's im- 

 pression that moraines proportional in size to the amount of material 

 eroded are seldom found at the mouths of cirques or troughs. Certainly 

 it is more usual to find but a fraction of the eroded material deposited in 

 the form of a terminal moraine. During the thousands of years that the 

 cirque is being carved streams from the melting ice are constantly carry- 

 ing away much of the erosion product, sometimes to deposit it as a valley 

 train or outwash plain, sometimes to transport it to more distant regions. 

 Indeed, theoretical considerations are not opposed to the hypothesis that 

 in many cases the amount of glacially eroded debris removed by stream 

 action might be so great that no significant morainal ridges would be 

 formed. The field experience of glacial students confirms this hypothesis, 

 for more than one has commented on the marked disparity in volume 

 between certain large cirques or troughs and their associated small mo- 

 raines. Prof. E. de Martonne, for example, informs me that in the 

 Carpathian Mountains, where no question of continental glaciation com- 

 plicates the problem, large moraines are surprisingly rare. Out of ten 

 glacial cirques, on an average not more than one or two would have 

 moraines of appreciable size, while the majority would have no true 

 moraines associated with them. The absence of important moraines op- 

 posite the mouths of White Mountain cirques, therefore, does not justify 

 the conclusion that such moraines were once formed, but were later re- 

 moved by the continental ice-sheet. 



