DEVONIAN SYSTEM. 
81 
Two of the best sections of the Devonian are furnished by the J. L. 
Thompson No. 3 well (46) and the Luse well (15), and these are given 
for comparison. 
Section of Chemung formation in the J. L. Thompson No. 3 well, borough of Deemston. 
Red rock ..... 
Sand 
Slate and shells 
Red rock 
Slate and shells 
Red rock 
Dark slate 
Red rock 
Sand 
Slate and shells. 
Sand, Bayard . . 
Slate and shells . 
Sand, Elizabeth 
Slate 
Cat skill beds 
Feet. 
20 
20 
30 
10 
55 
55 
10 
20 
25 
52 
15 
69 
12 
10 
Section of Chemung formation in the Luse well, near Beallsville. 
Red rock 
Slate and shells 
Red rock 
Slate and shells 
Red rock 
Slate and shells 
Sand, Fifth . . . 
Red rock 
Sand 
Catskill beds 
Slate 
Sand, Bayard. 
Slate 
Sand 
Slate 
403 
Feet. 
15 
40 
30 
51 
39 
65 
20 
28 
17 
85 
6 
28 
6 
73 
503 
Catskill (or sub-Blairsville) beds. — In all the complete records which 
penetrate the Chemung formation in this quadrangle an interval of 
100 to 300 feet near the top of the formation is occupied by two to five 
beds of red shale, separated by sandstone, shale, and shelly layers. 
Similar red beds, somewhat thicker but at approximately the same 
interval (900 to 1,100 feet below the top of the Big Injun) have been 
noted by M. R. Campbell in many wells in the Latrobe quadrangle 
and vicinity, and have been named the sub-Blairsville member, for the 
reason that the wells in which they were reported lie near the town of 
Blairsville, Indiana County. They are believed to be the westward 
feathering out of the Catskill formation, which, in eastern Pennsyl- 
