170 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



Feet. Inches 



1. Shales, with 2 feet red band at 25 feet from top 62 



2. Upper Mahoning sandstone 20 feet ") 



Upper Mahoning shale 10 feet (-45 



Upper Mahoning sandstone 15 feet J 



3. Philson coal [Upper Gallitzin] 6 



4. Limestone [Upper Mahoning] 5 



5. Fireclay, sandstone, rusty shale 20 



6. Gallitzin coal [Lower Gallitzin] Trace 



7. Black shale 4 



8. Limestone [Lower Mahoning] 4 



9. Lower Mahoning, mostly sandstone 55 



giving 133 feet for the Mahoning, with both Gallitzin coal beds accom- 

 panied by limestone. The Brush Creek limestone belongs in the upper 

 half of Number 1.* 



This conclusion respecting the relations of the Black Fossiliferous 

 limestone is confirmed by Stevenson's section on the Conemaugh river in 

 Westmoreland county near the Cambria line, where that limestone is 170 

 feet above the Upper Freeport and 30 feet above the top of the Mahoning. 

 The last consists of two sandstone plates, 45 and 50 feet respectively, 

 separated by 45 feet of variegated clays, in all 140 feet, with the Upper 

 Gallitzin directly underlying the upper plate, f The interval from 

 Upper Freeport to Gallitzin is 25, and that to the Brush Creek limestone 

 is 42 feet less than at 4 miles north in Cambria county. Within a mile 

 or two farther south the Upper Gallitzin is about 50 feet above the 

 Lower Mahoning and 10 feet below the Upper, and the Upper Mahoning 

 limestone underlies it by 6 to 20 feet. The Upper Gallitzin was seen 

 again at 3 or 4 miles southeast, where the Lower Gallitzin is present 

 though only 3 inches thick. Farther south, at 12 miles from the Cone- 

 maugh river and still on the east side of the basin, the Ames and Brush 

 Creek limestones were seen, 126 feet apart by barometer, each thoroughly 

 characteristic and the latter overlying the Brush Creek coal bed, 8 inches 

 thick. A coal bed, evidently the Lower Gallitzin, is at 100 feet lower. 



An incomplete section obtained midway in the basin near Ligonier 

 shows a Little Pittsburg coal bed at 60 feet below the Pittsburg, resting 

 on its limestone, which is persistent. Another coal, at 140 feet, with an 

 uncertain limestone, may represent the Little Clarksburg horizon. The 

 Morgantown sandstone, beginning at 160 feet and 115 feet thick, ex- 

 tends downward to the Ames horizon, while at 18 feet below it is a coal 

 bed correlated by Stevenson with the Elk Lick. It is the Harlem, and 



* W. G. Piatt: (H 4), pp. 76, 100, 103, 121, 125, 128. 



t The error of correlating the Upper Gallitzin with the Philson of Somerset county 

 affects the work of both W. G. Tlatt and Stevenson throughout the Second basin. 



