AMMONOOSUC GLACIER 287 



chrysolite. I know of no ledge to the north of their present situation from 

 which they could have been derived, while similar ledges abound farther 

 south." ** 



The statement as to location of these ledges and the type of rock con- 

 cerned is too ambiguous to permit a later investigator to either confirm 

 cr deny the opinion which Hitchcock presents. It may be remarked, 

 however, that since the Crawford House stands on the drainage divide 

 between the headwaters of the Ammonoosuc and Saco (see plate 13), the 

 theory that the drift came from the south would seem to require a local 

 glacial movement through the Notch from sources unmentioned and un- 

 studied on the south side of it. Without more complete and explicit 

 statement of the evidence, serious consideration can hardly be given to it. 



"Examples of transported boulders of Albany granite are more decisive of a 

 glacial movement down the stream. From o the mouth of New Zealand River 

 nearly to Bethlehem station are numerous blocks of this granite, six feet in 

 length. This rock is in place on the New Zealand River, but not on the Am- 

 monoosuc. Hence the fragments must have moved down the stream (also 

 Little River, in Carroll), and being too large for water transportation, require 

 the agency of a glacier. Rude striae, supposed to have been made at this 

 period, occur near the Wing Road in the river. The boulders are found as far 

 south as North Lisbon. I obtained a specimen there weighing about eight 

 pounds. No search has been made for them lower down. Their location in the 

 river and angular shape indicate transportation by a local glacier." 2i 



So far as the boulders below Bethlehem Junction are concerned, the 

 report seems to indicate that they are small enough to have been carried 

 downstream by the river. The occurrence of blocks of this rock 6 feet 

 long between Bethlehem Junction and the mouth of the Zealand Biver is 

 a matter of which I did not feel fully convinced in the field. In sections 

 of drift deposits beside the Ammonoosuc, below Zealand Biver, blocks 

 and boulders several feet in diameter of various types of granite and 

 gneiss are numerous, but I found none of the peculiar granite porphyry 

 which Hitchcock called the "Albany granite." A few cobbles and plenty 

 of well rolled pebbles of that porphyry were found in a gravellv fan at 

 the mouth of the Zealand Biver, but these were obviously torrent-carried 

 and can not be used as evidence of northward movement of a local glacier. 

 If Professor Hitchcock is correct in his report of large blocks of Albany 

 granite along this portion of the lower Ammonoosuc, the absence of ex- 

 posures of that rock north of the river is still a debatable question, on 

 account of the mask of drift and forest and the lack of thorough ex- 

 ploration. 



23 Loc. cit. 



24 Op. cit., p. 243. 



