Faulted Kegion of the Mohawk. 



35 



of the relations, and find that no fault exists. The overlying 

 formations are continuous around the valley, and they are 

 exposed in many outcrops. The supposition that there is a fault 

 at this point may be due to the fact that in the bank along the 

 east side of the stream there are clays containing a very large 

 amount of Utica slate debris which might be mi&taken, on casual 

 observation, for Utica formation in place. At a short distance 

 east, however, there are continuous vertical outcrops from the 

 Calciferous to Utica beds, matching those on the west side of the 

 valley. The presence of the small inclnsed area of crystalline 

 rocks is due to a slight anticlinal in this vicinity, which has 

 brouofht the crvstalline rocks within reach of the creek for a few 

 hundred yards. Down stream the southwesterly dips carry 

 the formations beneath the surface in regular succession. To 

 the northwestward there is first a slight downward slope in the 

 strata and in the underlyin:;C surface of the crystalline rocks, 

 beyond which the stream runs along the strike, so that in 

 ascending the valley we finally rise high into the Trenton 

 formation at Trenton Falls. 



Faults. 

 The Little Falls Faults. — The nature of the uplift at Little 

 Falls is shown in the following figure. 



Figure 1.— Cross section of faults at Little Falls, N. Y., north side of the Mohawk, looking north. 

 v. Utica slate. T. Trenton and Birdseye limestones. C. Calciferous sandrock. A. Archean. Verti- 

 cal scale somewhat exaggerated. 



This uplift gives rise to the most conspicuous topographic 

 feature of the Mohawk Yalley. Approaching Little Falls from 

 the east the long gentle slopes of the hills of Utica slate are 

 abruptly terminated by a high ridge crossing the valley from 

 south to north. The river cuts through this ridge in a deep, 

 relatively narrow^ goi'g^j lined with high cliffs of Calciferous 

 sandrock and crystalline rocks. In the eastern end of the gorge 

 the crystalline rocks rise in cliffs 100 feet high, to a high terrace 

 surmounted a short distance back bv cliffs of Calciferous sand- 



