lO NEW YORK STATE MUSEUM 



quadrangle. There is a small abandoned quarry near Clay station 

 and a small outcrop at Bridgeport on the Chittenango quadrangle. 



The outcrop of the comparatively hard Lockport limestone under 

 the less resistant Vernon shale with both strata dipping south caused 

 an obstruction to the north flowing streams. In the base leveling of 

 the region the limestone would remain as a ridge after the over- 

 lying softer shales were worn down to a plain which on subsequent 

 uplift would cause a damming of the streams and overflow over 

 the area of the softer rocks. During the glacial period the erosion 

 by the ice and the glacial waters further lowered the shale areas 

 south of the limestone outcrop, causing a depression in which the 

 water stood after the melting of the glacier, thus producing the 

 flooded area of Cicero swamp and the westward extension of the 

 flooded area in the Montezuma swamp district. 



CAYUGAN GROUP 



Saltna Beds 

 pittsford shale 



The Pittsford shale has not as yet been recognized in the Syra- 

 cuse area but this may be due to the fact that this horizon is con- 

 cealed by the heavy mantle rock rather than to the absence of the 

 shale. The first rock that has been observed outcropping above the 

 Lockport limestone is the Vernon shale. 



VERNON RED SHALE 



Overlying the Lockport limestone is a great thickness of argil- 

 laceous shales, red and variegated at the base, gray to drab colored 

 toward the top. Mingled with the upper gray shales are beds of 

 calcareous and magnesian limestones, gypsum and rock salt, merg- 

 ing at the top into argillaceous dolomites or waterlime beds. In 

 many of the older reports which followed Dana's classification, this 

 whole series of beds is called the Onondaga Salt group and the argil- 

 laceous division at the bottom is called the Salina group, in distinc- 

 tion from the overlying waterlime beds. The Onondaga Salt group 

 was divided into four divisions, the lower being the red shale, now 

 called the Vernon shale, from the village of Vernon, in Oneida 

 county. 



It is difficult to determine accurately the exact thickness of the 

 Vernon shales in this area. According to Prosser and Englehardt's 

 interpretation of the Gale's well record made in 1884, there are 392 

 feet in that well boring; the well started in the shale, but how far 



