690 



Repoet of the State Geologist. 



The Clinton group is shale bearing in its lower members in eastern 

 Wayne comity. It is a bright green shale and is about thirty feet thick. At 

 Sod us Point the shale is purplish. It occurs at other localities, but is very 

 thin, not more than two to four feet {Ibid., p. 59.) The second green shale 

 of the Clinton group is less brilliant in color and everywhere full of fossils. 

 It is well exposed at Rochester and at Wolcott furnace, in the banks of the 

 creek, where it is over twenty-four feet thick. The shale is probably fre- 

 quently calcareous. 



Niagara. Although a prolific shale formation in New York state, 

 the writer has not seen any exposures of it which were not either very sili- 

 ceous or calcareous, so that it would probably not work well for the manu- 

 facture of clay products. When ground and mixed with water it possesses 

 no plasticity. 



According to Professor Hall (Geology of the Fourth District of New 

 York, p. 80), the Niagara shale forms a member of great development in the 

 lower part of the Niagara group. It is a dark bluish shale which, on expos- 

 ure, forms a bluish grey, marly clay. It is well shown at Lockport, in the 

 sides of the gorge at Rochester, just below the railroad bridge, and at many 

 localities in Wayne and Monroe counties. The lower layers of the shale are 

 less calcareous than the upper ones. 



The following is an analysis of this shale, the sample taken from the 

 gorge at Rochester (Sixteenth Annual Report United States Geological 

 Survey, part IV, p. 569). 



Silica, 28.35 



Alumina, 10.47 



Ferric oxide, 1.90 



Lime, 21.47 



Magnesia, 8.24 



Alkalies • 5.73 



76.16 



H. T. Vulte, Analyst, 



The shale is also to be found in many of the ravines and gorges, from 

 Rochester to the Niagara river. 



SaMna. The shales of this formation are contained in a belt extending 

 from Syracuse westward along the line of the New York Central railroad to 



