982 NEW YORK STATE MUSEUM 



Olean conglomerate lie at a lower elevation than these underly- 

 ing beds do just to the south and east. 



The best development of this formation in the Salamanca 

 quadrangle is found on the ridge southwest of Limestone near 

 the Pennsylvania line. These two thin conglomerates again 

 occur just beneath the Olean. They are very well exposed along 

 the pipe line crossing this ridge. Each is more massive and 

 more conglomeritic than in the Knapp's creek area. The upper 

 one at least is fossiliferous. They are each 10 to 15 feet thick. 

 The shale interval between varies from 30 to 40 feet in thick- 

 ness and is fossiliferous, containing among other forms Syringo- 

 thyris again. There are about 25 or 30 feet of shale between 

 the upper conglomerate and the base of the Olean. Farther 

 south and west only one conglomerate known as the Subolean 

 has been seen by the writer beneath the Olean and the shale 

 interval is usually great enough to make it seem most probable 

 that this one conglomerate is the lower of the two in the above 

 mentioned localities, if both have not united westward. 



In some other places also these beds seem to have been 

 cut out by erosion before the deposition of the Olean conglom- 

 erate, as, for instance, on the ridge north of the head of Irish 

 brook, where Olean caps the hill but with no sign of an under- 

 lying conglomerate beneath. The same thing is true at Miller's 

 cliff in Warren county, Pa., where the Olean occurs, but 

 beneath it the Subolean is wanting. There is consequently 

 believed to be an unconformity between the Olean and the 

 underlying formations in this region and from differences of 

 level in the base of the Olean as exposed in outcrops often but 

 short distances apart, the floor upon which the Olean was 

 deposited must have been a very irregular one. 



Pottsville beds 

 Olean conglomerate. Next comes a massive round pebbled 

 conglomerate widely known as the Olean conglomerate. In 

 texture the Olean often varies quite rapidly both horizontally 

 and vertically. In some places or in some beds it is scarcely 

 more than a coarse sandstone with a sparing development of 

 pebbles, while at other places or in other layers at the same 

 place, it is almost entirely composed of rounded quartz pebbles. 

 If any rule holds good the lower part is more frequently con- 



