A Strati graphical Study 139 
Pottsville may be found practically on every hill rising from 150 
to 170 feet above the flood-plain of the major drainage lines (fig. 
i), while the upper part of the Pottsville shows conspicuously only 
in the southeast third of the township. At no point was I able to 
find the contact between the Pottsville and subjacent Logan. A 
probable reason for this condition has been given above. The 
thickness of the coarse phase of the Sharon member can be estab- 
Fig. 5. The coarse phase of the Sharon, showing cherty fragments and quartzite 
pebbles. 
lished with some degree of satisfaction by locating the fire-clay 
beds along the highway crossing the hill from Mary Ann Furnace 
to Wilkins’ Corners; several aneroid readings make this measure- 
ment approximately 38 feet. 
The Sharon wherever studied, is rather coarse, sometimes a 
conglomerate, locally showing vigorous stream work in the hetero- 
geneous mingling of materials; in a few outcrops the fragments 
weigh one to four pounds, and are subangular, but mingled with 
