PETROLEUM AND NATURAL GAS. 
53 
The interval from the Gantz sand to the Pittsburg coal seems to 
be more variable than that of any other persistent sand. Within the 
quadrangle it varies from 1,790 feet in the Ross well in Chartiers 
Township to 1,985 feet in one of the J. L. Thompson wells in the 
Zollarsville field. As with the upper sands, there is a gradual thick- 
ening of the interval from northweso to southeast, as shown by figures 
in the various districts. In Chartiers Township the variation is from 
1,790 to 1,821 feet; at Washington, 1,805 to 1,827 feet; in North and 
Fig. 3. — Sketch map showing the diminution of interval between the Pittsburg coal and the Gantz 
sand, corresponding to the unconformity at the top of the Mauch Chunk formation. A, Amity; B, 
Beallsville; E, Ellsworth; H, Houston; L, Linden; T, Tenmile; V, Venetia; W, Washington; Z, 
Zollarsville. 
South Strabane townships, 1,815 to 1,870; in North and South Frank- 
lin townships, 1,820 to 1,880; in the northwestern part of West 
Bethlehem Township, 1,877 to 1,883; in the Fonner field and vicinity, 
1,900 to 1,929; near Zollarsville, 1,890 to 1,955; west of Deemston, 
1,910 to 1,985, with two wells as low as 1,820 and 1,845; at Deems- 
ton and farther east, 1,910 to 1,970; southwest of Beallsville, 1,886 
to 1,933; south of Ellsworth, 1,910; northeast of Vanceville, 1,940; 
