PENNSYLVANIA^ SERIES. 23 
The original Gantz well at Washington shows a fair section of the 
Conemaugh, although in this well the base of the formation is rather 
indefinite. 
Section of Conemaugh formation in the Gantz well, Washington. 
Feet. 
Coal, Pittsburg. 
Sandstone, soft 10 
Slate 12 
Shells, hard 2 
Slate 10 
Sandstone, hard, gray 11 
Slate 30 
Sandstone, white, soft : 10 
Slate 51 
Sandstone, very hard . 80 
Slate 10 
Limestone . 5 
Slate 15 
Red rock 60 
Slate and shells 40 
Red rock 25 
Slate 32 
Red rock 25 
Sandstone, white 20 
Slate and shells 100 
Sandstone, hard, gray H)0 
648 
Coal and slate. 
As this total is greater than the usual thickness of the Conemaugh 
formation there is some doubt whether the "coal and slate" occupies 
exactly the Upper Freeport horizon ; but the lower limit of the forma- 
tion is approximately correct. 
In PL II are given records of eleven typical wells in the quadrangle, 
and by comparison of these records the relations of the various beds 
described and the limits of the formation can be seen. The coals 
denoting the upper and lower limits of the Conemaugh formation are 
shown in solid black sandstone by dotted S3mibols, slate or shale by 
continuous or broken parallel lines, limestone by the block symbol, and 
sandy shale by a combination of lines and dots. The correlation 
lines other than for coals are represented by dotted lines. 
ROCKS BETWEEN THE TOP OF THE UPPER FREEPORT COAL AND THE TOP OF THE 
POTTSVILLE SANDSTONE (ALLEGHENY FORMATION). 
Definition. — Underlying the Conemaugh is the Allegheny forma- 
tion, which may be defined as extending downward from the top of 
the Upper Freeport coal to the top of the Pottsville sandstone. This 
is the formation in which nearly all the workable coal beds in the lower 
part of the Pcnnsylvanian series occur. It was for a long time known 
