GLACIAL WATERS IN BLACK AND MOHAWK VALLEYS 25 



the south side of the Mohawk valley as the streams there are rela- 

 tively short and weak, the slope steep and the strata chiefly shale. 



Toward the close of the stage the Herkimer waters probably 

 extended from Utica to Johnstown. Its precise limits are miknown. 

 Plate 13 gives suggestion of an early phase. 



The evidences of standing water at high levels throughout the 

 Mohawk basin are abundant and conclusive. Above about 1200 feet 

 the features are chiefly the extensive sand plains by the northern 

 drainage, but below that level the proofs are more varied and very 

 common. Delta plains usually occur, at falling levels, along the 

 stronger streams and in hundreds of localities where the detritus 

 was not so abundant as to produce definite and conspicuous plains 

 we find silted hollows and sandy stretches. 



Below about 1200 feet the valley walls exhibit the peculiar 

 smoothness or softness of outline characteristic of wave-washed 

 slopes. Distinct beach lines are not uncommon and in some localities 

 the horizontal marking of the slopes due to wave erosion are strik- 

 ing. They are specially conspicuous in the Little Falls district where 

 the soft Utica shale of the valley walls combine with other factors 

 to favor their production. Some of these beach lines require for 

 visibility a viewpoint of proper altitude and a suitable lighting. 



The best example noted by the writer of the high-level beach lines 

 lies on the south side of the valley four miles southwest of Little 

 Falls, and may be clearly seen from the New York Central and the 

 electric railroads in all lights, but are specially prominent with a 

 sunset lighting. They are shown in the accompanying figure and in 

 plate 25. 



w^i/e- cut cliff 

 /30off:± '^■' 



700 Jkd: 



Figure i Sketch of beach lines produced by high-level waters in Mohawk 

 valley, four miles southwest of Little Falls. View from river bank two 

 miles southwest of village. Compare plate 25. 



In a former paper these horizontal lines were attributed to stream 

 work of ice-border drainage, but it is now found that they are the 

 product of lake waters. The highest wave-work that is evident on 

 the ground is at about 1300 feet, a cliff and terrace at the foot of 



