32 BULLETIN OF THE NEW YORK STATE MUSEUM 



underground contours of the salt measures, which accom- 

 panies this report. 



. In constructing this map the contours have been located 

 610 feet below the upper surface of the corniferous lime- 

 stone ; for the salt beds vary greatly in their thickness and 

 position in the Salina group, and it is necessary to assume 

 an horizon at which the occurrence of salt can be expected. 

 The contour line at the altitude chosen intersects the princi- 

 pal salt bed in nearly every well and shaft. 



Throughout the Oatka-Genesee district, salt is usually 

 found at levels varying from 550 to 750 feet below the 

 upper surface of the corniferous limestone. The exceptions 

 to this are very few ; the only ones which have come to the 

 notice of the writer being the wells at Nunda and Bliss, in 

 the former of which, salt was found between 450 and 500 

 feet below the corniferous, and in the latter it was first met 

 at a depth of 900 feet. In the Ithaca well the lowest bed 

 of rock salt was over 1000 feet below the upper surface of 

 the corniferous. The testimony of the two latter wells 

 would suggest that as a rule the wells and shafts of western 

 New York have penetrated little more than half way through 

 the salt measures. The upper surface of the corniferous 

 limestone has been taken as the datum plane from which 

 to determine the relative positions of the salt beds, because 

 it is invariably recognized by the driller as soon as reached. 

 Its persistent character and the abundance of chert distrib- 

 uted through it, form a marked contrast with the com- 

 paratively soft shales and thin limestones which overlie it. 

 From the underground contours as shown on the map, it 

 will be seen that the dip of the strata in western New York 

 is not directly to the south, but nearly south-east at the rate 

 of about 60 feet to the mile. The section as plotted be- 

 tween Le Roy and Gainesville Creek shows that the beds 

 do not slope uniformly to the south east but undulate in 

 that direction. 



