40 



NEW YORK STATE MUSEUM 



base of the dolomite comes against the fault at about 800 feet ele- 

 vation which means that the Precambric rock surface on the east 

 side of the fault lies at an altitude of something like 600 feet. But 

 the Precambric just west rises to 2140 feet so that the amount of 

 displacement is here at least 1540 feet. 



JACKSON CREEK FAULT 



One and one-half miles west-northwest of Cranberry Creek a 

 fault, apparently a branch of the Noses fault, strikes southwest 

 through the Precambric and has its upthrow side on the west. It 

 has been traced for two miles as a distinct topographic feature 

 and by occasional outcrops of brecciated Grenville. Such brecciated 

 Grenville is beautifully exhibited where the fault runs parallel to 

 the private road near the map edge. This fault probably joins the 

 Noses fault to the east of Jackson summit on the Gloversville sheet. 



EZl^WCCAM BRIO ^ScRtMVlLLt. liliJ SVE N ITC. LlJ POTS DJ^M. feSjTHIUCtA 



iT^i rTTl r FALLS t^'J TR £ N TO N. I^-~1 CANAJOHAniC fV«l D « i r T. 



SCALE: 



Fig. 5 North south section from a point two miles west of Cranberry Creek to a point one-half 



of a mile southeast of Mayfield station 

 Fig. 6 Northeast-southwest section from a point one mile east-northeast of Cranberry Creek 



to a point one and one-half miles due north of Mayfield 



ROBERTS CREEK FAULT 



One and one-half miles west of Cranberry Creek another dis- 

 tinct fracture branches off the Noses fault. It strikes a little east 

 of south and can be traced for about two miles after which its 

 course is uncertain. The upthrow side is on the west which ac- 

 counts for the presence here of the tongue of Grenville gneiss 

 extending out from the main Precambric area. Potsdam sand- 



