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NEW YORK STATE MUSEUM 



its throw is reduced to zero. Followed northward from its first 

 point of appearance, its throw increases with unusual rapidity, 

 as noted by Barton. 1 The last point of identification is at the 

 High falls, below Dolgeville, beyond which it can not be traced 

 because *of utter lack of outcrops for several miles. 



Where the fault crosses the creek, its most southerly point of 

 exposure, the creek has a rock bottom, and the section furnishes 

 interesting evidence of the manner in which the fault is dying out. 

 The dips are rather high, from 30 to 60 on the downthrow side, 

 and the layers have been beveled to an even surface by the cutting 

 action of the stream, so that at low water the section shows mag- 



Fig. 7 Plan and section to illustrate the conditions where the Dolgeville fault 

 crosses East Canada creek. Trenton limestone is at the surface on the east side, and 

 the alternate shales and limestones of the passage beds on the west. The divergent 

 strike brings lower beds in succession to the surface on the west, or downthrow side, 

 and higher beds on the east side, with consequent diminution of throw. 



nificently. Figure 7, though not an accurate scale drawing, repro- 

 duces the observed conditions quite faithfully. There is a breccia 

 zone a few inches wide along the fault line. The spreading pro- 

 duced by swerving of the strike is most marked on the west side, 

 which coupled with the high dip there, brings successively lower 

 layers to the surface with some rapidity. The fault seems to pass 

 into a monoclinal fold southward, which fades out in its turn, 

 and this seems a step in the transition. 



Some 50 rods north of this point another smaller fault 

 appears in the east bank of the creek. It shows Utica shale on 

 both sides and has but an insignificant throw. Judging by the 



1 Darton gives four sections across this fault, op. tit. p.41. 



