206 



Repokt of the State Geologist. 



The greatest thickness of the Red shales on the line of the northern out- 

 crop of the beds, is in Onondaga and Cayuga counties. In the Gale well at 

 Syracuse, which was begun near the top of the formation, they are 525 feet 

 thick. 



The area of surface exposure and the thickness of the beds diminishes 

 rapidly towards the east across Madison county and the southern part of 

 Oneida county, and they do not outcrop east of Herkimer county. 



They also apparently become much thinner toward the west, but to what 

 extent the difference is to be attributed to a lessened degree of sedimentation, 

 and how much to changes in the character of the deposits, is not known. 

 The changes are so gradual that in the absence of opportunities for care- 

 ful examination of cross sections the thickness of the strata belonging to this 

 division can only be estimated. 



In the Le Roy well, the record of which has been published by I. P. 

 Bishop, they are more than 300 feet thick ; at Batavia about 250 feet and in 

 the "well at Gardenville, Erie county, not much more than 200 feet thick. 



The deep wells drilled for salt usually end in, or at the bottom of the 

 rock salt bed, but in one of the wells of the Standard Company, at Warsaw, 

 the red shale below the salt was penetrated to the depth of 10-1 feet, and in 

 the test well at the Livonia salt mine, 115 feet. 



In the Ithaca test well, drilling ceased in shales of this formation 471 

 feet below the lowest bed of salt, and in the Morrisville well, 519 feet of 

 these red and green shales were found overlying the Lockport limestone. 



Next above the red shales as described are the rock salt beds of the 

 state. 



Although these ' beds are known to extend from the Oatka valley in 

 Wyoming county to Morrisville, Madison county, and as far south, with in- 

 creasing thickness, as wells have been drilled to their horizon, they nowhere 

 come to the surface, and our knowledge of their condition and magnitude 

 has been obtained entirely from the deep Avells and mine shafts. 



The wells to the number of nearly 200 are distributed over almost the 

 entire area in which the salt beds are sufficiently near the surface to make 

 it practicable to reach them by drilling, but opportunities for examination 

 of the suit beds and adjacent rock strata in place are confined to a very small 

 portion of the district. 



Five vertical shafts about twelve by eighteen feet have been sunk as 

 mine entrances, two of which are at the Retsof mine in the town of York, 

 Livingston count)', and one at the Greigsville mine, less than a mile distant. 



