40 TRANSACTIONS OF THE [NOV. 18, 



In a large number of the deeper wells bored for oil in western 

 Pennsylvania and Ohio, salt water was obtained. The produc- 

 tion of salt from the brines of wells bored as salt-wells on the 

 upper Alleghany, had become an important industry long before 

 petroleum was sought for by boring; indeed, the quantity of 

 petroleum in the wells at Tarentum first suggested to Mr. J. 

 M. Townsend and Col. Drake the possibility of procuring pe- 

 troleum in large quantities by sinking wells where the '•' surface 

 indications" were strongest on Oil Creek. But none of these 

 "wells went deep enough to reach the salt-horizon, which we now 

 know is the Salina group of the Upper Silurian system. 



When, however, the oil-field of Pennsylvania was shown to 

 extend into New York, many wells were bored in the upper val- 

 ley of the Genesee. Little or no oil was obtained from these 

 wells, however, for they were sunk below the oil-horizon ; yet 

 some of them reached down to the Salina group and very unex- 

 pectedly revealed the presence in it of heavy beds of rock-salt. 

 In the upper part of the valley the salt-horizon was found to be 

 2,500 feet below the surface, but in the wells bored about Gene- 

 seo, the rocks all rising toward the north, the salt-beds were 

 reached at from 800 to 1,500 feet. At one of these wells, the 

 *'Eetsof," situated near Piffard, N. Y., a siiaft was sunk to ths 

 salt, and it is now extensively mined. It proved to be of great 

 purity, similar indeed to that of Goderich, and by simple grind- 

 ing furnishes a table salt of a quality superior to that produced 

 at Syracuse or Grand Rapids. 



The extent of the rock-salt beds of the Salina group is not yet 

 known. The point furthest north where they have been reached 

 is at East Aurora, seventeen miles from Buffalo, where they lie 

 1,350 feet below the surface. West of this point, the rocks all 

 dip westerly and the Salina group is deeply buried under the 

 basin of Lake Erie, until we approach the Cincinnati arch, where 

 it rises to the surface near Sandusky. It here contains no salt, 

 but heavy beds of gypsum which are profitably worked. 



Along the south shore of Lake Erie many wells have recently 

 been bored for gas, and in one of these, at Cleveland, Ohio, a bed 

 of rock-salt 164 feet in thickness was reached about 2,000 feet be- 

 low the surface. Another well bored long ago for oil, near Ash- 

 tabula, Ohio, yielded a very strong and bitter brine. This has 

 I'ecently attracted attention and has been analyzed with unexpected 

 results. The analysis was made by Stillwell & Gladding, chem- 

 ists, No. 55 Fulton street. New York. The water filtered from 

 the sediment contains in one U. S.-wine gallon the following : — 



Silica , 2.91 grs. 



Oxide of iron and alumina 8.73 " 



