14 J. W. Goldthwait— Glacial Cirques 



appeared and have survived the strong regional glaciation. 

 The cirque-like form of the basins on the side of Mount 

 Ktaadn likewise was regarded by Tarr as the record of a 

 " closing stage " of the glacial period. On theoretical grounds, 

 however, Tarr conceived that there had been snow fields on 

 the New England mountains during the coming on of the 

 glacial period also, and that local glaciers had been nourished 

 from several centers before the ice sheet reached this field. 

 Indeed, he went further than this, and suggested that probably 

 the glaciation of northern New England included (a) the 

 development of local valley glaciers on the highest ranges ; (h) 

 the growth of these local snow fields into several local ice caps : 

 (c) the period of continental glaciation, when the larger ice 

 sheet from Labrador overwhelmed the smaller ice caps; (d) 

 the re-establishment of local ice caps which spread both 

 northward and southward from the International boundary, and 

 (e) the disappearance of all save valley glaciers on Mount 

 Ktaadn and the highest White Mountains. Without attempt- 

 ing to controvert the evidence of Agassiz, Hitchcock, and 

 Tarr, which deserves detailed study in the field, I must point 

 out that the facts observed last summer seem to show T that 

 although valley glaciers acted long and vigorously before the 

 advance of the ice sheet into the White Mountains, they did not 

 reappear when the ice sheet withdrew, or, at most, were com- 

 paratively insignificant. The reasons for this conclusion may 

 now be briefly stated. 



If the cirques in question had been excavated by valley gla- 

 ciers in the closing stages of the ice age, one ought to find ter- 

 minal moraines near the mouths or in the valleys beyond, and 

 crescentic recessional moraines farther back, marking oscilla- 

 tions of climate during the final retreat of the glaciers. On 

 the sides and floors of the ravines lateral and medial moraines 

 might be expected. 



We have seen that Tarr considered mounds and ridges of rock 

 debris in the Ktaadn basins to be moraines, although the heavy 

 forest which covered that country largely concealed the form 

 of the ground. Much reliance was placed by him on the pres- 

 ence of lakes which seemed to be held in by moraines. In the 

 more open and accessible ravines of the Presidential Range there 

 is comparatively little difficulty in seeing and following the 

 ridges and piles of rock waste. My expectation of discovering 

 moraines in the ravines around Mount Washington, however, 

 was not realized. The first surprise came when we commenced 

 work, in King's Ravine. The upper end of this ravine, for 

 half a mile between the headwall and Mossy Fall, is occupied 

 by a mass of blocks, the outer edge of which is distinctly lobate. 

 The blocks are all of mica schist like the rock in the headwall 



