Stevenson. 17 
Chemung and Catskill. 
to the Lackawaxen is 568 feet; in the deep boring at Pittsburg 
it is given as 519 feet. 
Mr. J. H. Carll has tabulated the oil-well records in the west- 
ern oil-bearing counties of Pennsylvania, and we must depend 
largely upon his work as we follow the series northward in west- 
ern Pennsylvania; though one may sometimes fail to accept his 
identifications, yet all must acknowledge the patience with which 
he has worked and the excellence of his results. 
At Washington, about thirty miles southwest from Pittsburg, 
the interval to the Lackawaxen is from the top of the Pocono is 
518 feet, and the rock is termed by Mr. Carll, the ‘‘gas sand.’* 
The section there is 
Pocono (Shenango sandstone of White) 152’ 
Interval 366 
Lackawaxen conglomerate 20’ 
Interval 87’ 
Gantz oil sand 40’ 
The Pocono has become less coarse. At Pittsburg it contains 
much shale, while in Washington county its sandstone is often 
less than 150 feet thick. 
Mr. Carll recognizes in the Gantz sand, the upper or first of the 
Venango group of oil-sands, which consists of three well marked 
sandstones separated by shales and showing few variations in 
Venango county. It is not easy, however, to accept this identifi- 
cation after a careful study of his sections as tabulated in the 
Annual Report for 1886, and I am compelled to regard the upper 
gas sand of Weirick’s well as the first oil sand of Venango, and 
as the Lackawazxen.t The distribution and variations of the 
“Venango group are shown in the very numerous records of oil- 
wells which Mr. Carll has preserved and published in his volumes 
on the western counties of Pennsylvania. <A section on Thorn 
creek{f in Butler county, at about thirty miles northward from 
Pittsburg gives 
Shenango sandstone (of White) 
Interval 395 ' 
(Lackawaxen) first Venango oil sand 45' 
Interval 420’ 
(Allegrippus) third Venango oil sand 46' 
*Carll in Ann. Report of 2d Geo]. Survey of Pennsylvania for 1886, p. 
656. See plate Plate 5 figs. 20 and 21. 
+See fig. 21 of Plate 5. 
{Carll in Report for 1886, p. 650. See Fig. 19 of Pl. 4. 1 have con- 
densed the section and inserted the names of the sands. 
