Notes ok the Geology of Yates County, N". Y. 201 



Genesee Slate. . 



The next formation m the natural order downward is the Genesee 

 slate. This extends the entire length of the county from north to 

 south, and there are many fine exhibitions of the entire thickness of 

 the dark, fissile carbonaceous shales, but the fossil remains are but 

 sparingly distributed. In a ravine near Shingle point, on Seneca lake, 

 there is a stratum about two feet thick, and near the middle of the 

 formation, which abounds in fossils, among which are the following : 



Lepidodendron, sp. ? Very large and fine. 



Goniatites, sp. f Very large and fine. 



Leiorliynchus quad?Hcostata,Y'dnuxem. 



Lingula spatulata, Vanuxem. 



Discina Lodensis, Vanuxem. 



Distinct, iruncata, Hall. 



Also a large number of small gasteropods. 



'Septaria of all sizes from a few inches to two feet in diameter and 

 of many curious shapes occur plentifully. The major part of them 

 are over ten inches in diameter and flattened. They usually contain 

 cavities which are lined with crystals. Usually the calcareous filling 

 in the septse and the body are worn away unequally, producing many 

 curious forms, and many of the people along the exposure of these 

 shales possess their " petrified turtles." 



This is the first formation encountered in passing down the outlet 

 of Lake Keuka (Crooked lake). At Kandall's Mills these shales form 

 an abrupt cliff seventy feet high and intensely black. They extend to 

 the Oil mill, a mile below where the water tumbles over a cascade of 

 fourteen feet, formed by the Tully limestone. 



Fault ik the Outlet of Lake Keuka. 



©SSsSllfc^ 



Fig. 3. — Section in outlet of Lake Keuka, showing a fault of forty feet which occurs near 



the Oil mill. 



It seems proper at this point to describe what we believe to be a 

 fault which occurs in strata at the outlet. 



At the Oil mill the Tully limestone and Genesee slate are almost level 

 [Sen. Doc. No. 38.] 26 



