34 



NEW YORK STATE MUSEUM 



Potsdam sandstone. The best exposures of this rock are to be 

 seen about 300 yards directly east of the CathoHc church and high- 

 way bridge in the southern end of the village. No one of the 

 several good outcrops shows a thickness of more than 6 or 8 feet, 



Mt. Orrey 





Sea Igvel 



Canajoharie ^^3 BlackRiVer-Trenion CZZIZ] Little Falls 



shale r ' ' I Ifmesfoncs y i fi \ dolomite 



Fttsdam- Theresa 

 sandstone A-dolomife 



rx]Syenire 





Gr« ni+i'c 

 syenite 



^ c^ lA Precambnc 

 t^ ^- rock 



HORIZONTAL SCALE 

 MILE 1 



VERTICAL SCALE 

 O Mill % 



Fig. I Detailed structure section along the line AA (see geologic map) 

 across the valley (Paleozoic rock outlier) at Wells 



though, considering the positions of the outcrops, a thickness of 

 no less than 20 feet is certainly shown here. As nearly as could 

 be determined, the I04ofoot contour marks the summit of the 

 Potsdam whose beds lie in almost horizontal position though with 

 a very slight westerly dip. Immediately above and below the 

 river bridge, granite outcrops in the river bed at altitude 980 

 feet, but no Potsdam is there visible. 



The rock is a rather pure, white to light cream-colored, thin 

 to rather thick-bedded sandstone. Cross-bedding and ripple- 

 marks are common but pebbles are scarce. The quartz grains are 

 well rounded. Upward the rock grades into the Theresa tran- 

 sition series due to the appearance of dolomite beds. 



In 1898, according to Kemp, the Potsdam was visible in a pit, 

 8 or 10 feet deep, immediately east of the hotel (Wells House) 

 at the northern end of the village. This exposure could not be 



