22 NEW YORK STATE MUSEUM 



Vernon shale. The thickest member of the SaHna beds is the 

 Vernon shale* It is a soft shale which by its usual deep red color 

 can be distinguished more or less readily from the shales above the 

 salt horizon. The strong ferric-oxid color is particularly prevalent 

 in the eastern section where the beds can be traced across the 

 country by the red, greasy clays that result from their decompO'Si- 

 tion. In the western part they are banded with greenish and gray- 

 ish layers and bear some resemblance to the Medina shales. They 

 are exposed from Herkimer coimty westward across Oneida, Mad- 

 ison, Onondaga and Cayuga counties, but beyond the Genesee river 

 are generally buried under the drift, and as their color is no longer 

 uniform, their line of outcrop is not so readily determined in that 

 part. Thin layers of limestone also appear in the western counties, 

 as shown in well sections. 



The thickness of the A^ernon shale reaches a maximum in Onon- 

 daga and Cayuga counties, where it probably averages about 500 

 feet. At Syriacuse the salt well section shows 525 feet. Toward 

 the east the shale thins rather rapidly and apparently disappears 

 entirely in Herkimer county. Westward its thickness also- dimin- 

 ishes, but from the information afforded by the few wells that have 

 penetrated the wSalina the shale seems to persist as far as Erie 

 county at least. At Gardenville, in that county, a well record shows 

 200 feet of shale below the salt horizon. Most of the salt wells 

 and shafts do not go below the lowest salt, though in one well at 

 Warsaw the shale has been penetrated for a little over too feet. 



The absence of any extensive deposits of gypsum in the Vernon 

 shale is a noticeable feature, and one which seems to detract from 

 the vahdity of the usually accepted view that the salt and gypsum 

 beds are due to evaporation of sea water. If the sea during Siluric 

 times approximated in composition the ocean of the present day as 

 regards saline constituents — and the evidences strongly indicate a 

 similarity of conditions — there should be a considerable deposit of 

 gypsum below the salt beds. It is fairly certain, however, that the 

 salt and gypsum do occur in their normal order. In some of the 

 deep wells, as for instance at Attica and Aurora, gypsum was foinid 

 below the salt, while there may be a large amount of gypsum in 

 the aggregate disseminated through the mass of the Vernon shale, 

 as has been suggested by Hartnagel.^ It can only be said that the 

 conditions generally were less favorable for the deposition of large 

 and continuous beds of gypsum in the Vernon shale than later in 



' Geologic Map of Rochester and Ontario Beach Quadrangles. N. Y. 

 State Mus. Bui. 114. 1907. p. 30. 



