248 SURFACE GEOLOGY. 



come down the mountain. The greatest angle of descent, 42°, occurs in the upper and 

 lower of the four sections, and the least angle of 18° is in the third section from the 

 top. The minimum widths of the four sections are 10, 15, 20, and 30 metres; the 

 maximum 15, 20, 30, and 90 metres. The minimum depths of the excavation were 15, 

 10, 5, and 3 metres; the maximum 18, 15, 10, and 10 metres. 



Mr. Sweetser, in his guide-book, speaks of a line of boulders in the Carter Notch 

 which may have had some connection with glacial action. At the south entrance of 

 the Notch is a lofty line of immense boulders, piled on each other in inextricable confu- 

 sion, and affording some of the most remarkable rock scenery in the mountains. They 

 are rugged and deeply pitted, like the rocks on the cone of Mt. Washington, and 

 may have been derived from the crests of the adjacent peaks. One or two of these 

 boulders are near seventy feet long each. 



Returning to Jackson, we find a tributary of the Wildcat coming from 

 the north-east, and uniting with it about a mile above the falls, which 

 ought to show a few glacial traces. I found nothing very characteristic, 

 unless it were a few boulders of a peculiar porphyritic granite. I think 

 these must have been derived from the north, as nothing like them is 

 known in ledges west of Mt. Baldface, or " Peaked," a summit so called 

 by Packard, and not named upon our map. The striae upon these moun- 

 tains do not point towards Jackson, as they belong to the older set. Mr. 

 Packard says, — " On the summit [of Baldface, where the striae run S. 

 23°-28° E.] rest several angular boulders of a peculiar porphyritic sienite, 

 containing curious oblong crystals of albitic feldspar. Our guide to their 

 source — the trusty ice grooves — points to Peaked mountain ; " and, by 

 investigation, he found the rock in situ upon that eminence. The por- 

 phyritic boulders found by me did not come from the mountains men- 

 tioned by Packard, as the rubbish derived from them would have gone 

 down the east branch of the Saco, joining the main stream in Lower 

 Bartlett. Further search will develop evidences of the existence of this 

 glacier in the east branch. Packard speaks of staurolite mica schist 

 boulders on the north flank of Mt. Pequawket, saying "they must have 

 been borne down on the back of the glacier from Mt. Washington." 

 This is hardly probable, since the rock occurs on both the north and 

 south sides of Pequawket, and the boulders are even more abundant on 

 the south side of the mountain. Jackson Falls village is situated in a 

 hopper-shaped depression considerably open on the west side. Pickett, 

 Thorn, and Tin mountains constitute the north and east rims. Black and 



