Faulted Region of the Mohawk. 



43 



beds of clay and boulders. This exposure is now covered and is 

 no longer accessible. The course of this main fault is very clear 

 nearly to the point at which it bends to the southeast to cross the 

 Mohawk, where it is covered by drift. The relations in this 

 vicinity, so far as known, are shown in the following section 

 which crosses the loop in the main fault. 



^^^.^^ 





t^'r:-. 











!I9 



Figure 7.— Section aci-oss the Mohawk just above St. Johnsville, N. Y., looking west, 

 slate, r. Trenton and Birdseye limestones. C. Calciferous. 



U. Utica 



The relations of the recurved portion of the fault on the south 

 side of the river are clearly exhibited in every detail. The fault 

 plane is not exposed, but the Utica slate and Calciferous are 

 seen within a few feet of each other in the west bank of a small 

 brook, and the course of the fault is seen to be due north-northeast 

 down to the mouth of this brooklet. The slate is tilted back to 

 the eastward in the usual manner, for several rods from the 

 fault. The Trenton and Birdseye limestones on the uplifted side 

 dip to the southwest, which carries them from an altitude of 150 

 feet above the river near the fault to below the river a short 

 distance east of the East Canada creek fault. Both the main and 

 branch faults are lost in the high region of Utica slate a short 

 distance south of the crest of the southern bank of the Mohawk 



To the northward, the principal fault increases in amount and 

 brings up the crystalline rocks in an area which widens and rises 

 rapidly in the next few miles. Along by Garoga the scarp of 

 crystalline rocks is very high and precipitous. The Utica slate 

 east of the fault underlies the depression eastward. IS^orth of 

 Rock wood the crystalline rocks come up on the east side of the 

 fault. North of this vicinity the fault was not traced, but it 

 probably extends far into the Adirondacks. 



The ^^Noses " Fault. — This great uplift crosses the Mohawk 

 river five miles below Canajoharie. It is very similar to that of 

 Little Falls, giving rise to a great ridge of Calciferous, rising ab- 

 ruptly from the moderately elevated Utica slate region eastward. 



