204 Wilson — Glaciation of Orford and Sutton Mis., Quebec. 



number of erratics were found between 300 and 500 feet below 

 the top. These included several pieces of a coarse grit which 

 was probably derived from a basal member of the Potsdam 

 formation, fragments of schists from the valley to the north- 

 west, and a fragment of a coarse pegmatitic granite. At 300 

 feet below the summit a large bowlder of Laurdalite from 

 Brome Mountain, 14 miles to the northwest, was found. 

 Several similar pieces were picked up below this contour. 



The most interesting feature of Sutton Mountain, however, 

 is the occurrence of a series of remarkably w r ell developed 

 Y-shaped notches which cross the summit of the main ridge in 



Pt^SJy 



RlfejS 





. [A 





i^JT'WC!! rr? 





^^^KtfgV'' . "sN-* 





vhiSfr 







:-- ■'*" ." , ■ '■' 









tf^2*w^BH 



















Figure 5. Summit of Sutton Mountain. A V-notcli ten feet in depth 

 with, smooth sides, cut in gneiss, looking northwest. 



a direction about S. 25 E. The sides of these small notches 

 are planed off very smoothly, the west sides being the smoother 

 of the two, in each case examined. The depth of these notches 

 varies from four to about ten feet. The west side of one had 

 a dip of 50° and the east side of the same notch was only a 

 little less steep. This notch, whose form may be taken as 

 typical of the form of all of them, was about ten feet deep and 

 the ridges between it and the adjacent notches on either side 

 had sharp crests as well defined as the ridge of the roof of a 

 house. On the striated sides of these notches the large quartz 

 masses in the gneiss were found planed off even with the rest 

 of the surface. In all, twelve of these remarkable gullies were 



