42 NEW YORK STATE MUSEUM 



field than on the map. The upthrow side is on the north and con- 

 sists of Little Falls dolomite which, near the fault, contains white 

 chert and is more or less broken. Dolomite also makes up the 

 downthrow side except for a long narrow wedge of Trenton lime- 

 stone with more or less Lowville limestone. This limestone wedge, 

 which is never over seventy-five yards wide, is badly broken and 

 shows varying dips. The Little Falls dolomite here shows a thick- 

 ness of about one hundred and fifty feet and, at the map edge, the 

 Trenton is sharply faulted against its base so that the displacement 

 is approximately one hundred and fifty feet. This fault seems to 

 cross the Roberts creek fault at right angles near the railroad but 

 the relations are here wholly uncertain because of heavy drift. 



CRANBERRY CREEK FAULT 



This interesting dislocation runs nearly parallel to the Noses 

 fault, the writer having traced it with considerable certainty along 

 a north-northeast strike from a point about one mile north-north- 

 east of Mayfield, past the village of Cranberry Creek, to a point 

 about one and one-half miles south of Sacandaga Park. Its 

 northern extremity is obscured by drift. Between Cranberry Creek 

 and Mayfield the relations are somewhat complicated because of 

 the Roberts creek cross fault which causes the upthrow side to 

 be now on one side and now on the other, due to tilting of the 

 strata during the adjustment of the earth blocks and we have here 

 a fine illustration of pivotal faulting. 



One mile north-northeast of Mayfield the upthrow is on the east 

 with lower Little Falls dolomite (containing chert) faulted against 

 upper dolomite. Fault breccia is here shown and the throw of the 

 fault must be something over one hundred feet. A mile farther 

 northwestward the dolomite comes against the Grenville so that 

 here the upthrow side is on the west with an amount of throw prob- 

 ably in the neighborhood of two hundred feet. Just after cross- 

 ing the Roberts creek fault the relation is again changed and the 

 upthrow is on the east because of the wedge of Black River-Trenton 

 on the west side. Where the fault crosses Jackson creek the rela- 

 tion changes again so that the upthrow side is on the west. This 

 is shown by the small area of the Theresa formation. From here 

 northward the upthrow continues on the west. Where the fault 

 crosses Cranberry creek the strata are disturbed and good ex- 

 posures of the cherty beds of the lower Little Falls dolomite are 

 seen on the upthrow side. From a point about a mile north of 



