STRATIGRAPHICAL ORDER. 3 
to. Neither this stratum nor the one below it is characteristically a con- 
glomerate in Western Pennsylvania, but both are best described as con- 
glomeritic sandstones. To this upper stratum, various names have been 
assigned. In the reports of the First Survey it was frequently called 
the Tionesta Sandstone. In the reports of the Second Survey it is 
designated not only by the old name, but by two additional names, viz., 
the Piedmont Sandstone and the Homewood Sandstone, the latter of 
these being most frequently used. 
These several elements constitute the Conglomerate Group, accord- 
ing to the most recent statements. A few feet above the Homewood 
Sandstone in riormal sections, the Brookville coal, or Coal A of Les- 
ley’s earlier series, is found. The composition of the group is more 
clearly shown in the following diagram, Fig. 1, which is copied from 
Professor I. C. White’s Report on Mercer county, Q 3, Second Pennsyl- 
vania Survey, page 33. The diagram is designed to give the typical 
section of the Conglomerate or Inter-conglomerate measures in Mercer 
county. The average actual thickness of this division in the counties 
bordering on the Ohio line is about 250 feet. 
Tt will be observed that four regular coal seams, viz., the Sharon 
coal, the Quakertown coal, the Lower Mercer and the Upper Mercer 
coals, have a place in this series, three of them being widely known and 
worked, and one of them, the Sharon coal, being of great economic im- 
portance. 
