CONCLUSION 551 



lake (plate 42, figure 2) is held in by a very perfect moraine dam, showing 

 good knob and kettle topography. It does not seem possible to regard 

 these ridges as the product of any agency but ice. It is equally impossi- 

 ble to regard them as deposits from tongues of the continental glacier 

 moving up valley. Their position seems clearly to negative the sugges- 

 tion that ice spilling across cols at the valley heads might account for 

 their existence. The only reasonable interpretation seems to be the one 

 already offered by Eich; they are terminal moraines of true local glaciers. 

 In the writer^s opinion these glaciers were very small and probably very 

 short lived. The moraines may mark their maximum extension down 

 valley. Good cirque topography is lacking, and the bulk of the morainic 

 debris may have slumped down from the valley head without the aid of 

 any appreciable cirque-cutting by the incipient glacier. 



The date of local glaciation in the Catskills seems scarcely open to 

 question. No moraines could preserve the delicate features characteristic 

 of the Fly Brook and Little West Kill ridges had they been overridden 

 by the continental ice. There can be little doubt that the Wisconsin ice 

 covered the low altitudes at which the moraines occur when the ice-front 

 lay in the latitude of Long Island. Later fluctuations of the ice-margin 

 may have failed to reach the localities in question ; but that local glacia- 

 tion occurred subsequent to the main advance and retreat of the Wiscon- 

 sin ice seems assured. 



Conclusion 



To the criticisms urged against certain of the arguments advanced in 

 support of an early date for local glaciation in the White Mountains we 

 have added evidence that the new theory can not successfully be applied 

 in the Adirondacks and Catskills. Tarr's description (1900) of lateral, 

 medial, and terminal moraines of local glaciers on Mount Ktaadn indi- 

 cate that equal difficulty may be encountered in attempting to apply the 

 theory in the mountains of Maine. These considerations justify further 

 study of White Mountain physiography before Goldthwait's theory is 

 accepted for that region. 



Eeferences 



J. W. Goldthwatt: 1913. (a) Following the trail of ice-sheet and valley gla- 

 cier on the Presidential Range. Appalachia, volume XIII, 1913, pages 

 1-23. 



: 1913. {!)) Glacial cirques near Mount Washington. American Jour- 

 nal of Science, fourth series, volume XXXV, 1913, pages 1-19. 



