54 J. J. STEVENSON CAEBONIFEROUS OF APPALACHIAN BASIN 



lies its coal bed. • The Benwood is represented by several thin beds. 

 Farther south the Lower Sewickley becomes variable, 1 to 5 feet, the 

 Bedstone coal is but one foot 6 inches and its limestone disappears.* 



The Greensburg hasin. — This is a canoe within central Westmoreland 

 in which the Monongahela passes out southwardly at a few miles south 

 from the Pennsylvania railroad. The strong Blairsville and Saltsburg 

 anticlines separate it from basins at the east and west. It retains two 

 small but important areas of Monongahela. The section reaches to fully 

 400 feet above the Pittsburg coal bed, but the shales and limestones 

 break up under the weather so readily that there are no natural ex- 

 posures. Long, deep cuts on the railroad east and west from Greens- 

 burg give this section: 



Feet Inches 



1. Limestone 2 6 



2. Shale and limestone 119 



3. Shale , 40 



4. Coal bed 3 4 



5. Shale and flaggy sandstone 48 



6. Limestone and shale 26 



7. Shale 48 



8. Pittsburg coal bed: 



Feet Inches Feet Inchei 



Coal and shale 2 6 to 5 4 



Shale 9 to 18 



Clay and coal, roof 3 to 5 8 



Clay 6 to 3 



Coal 6 6 to 7 8 



The main division of the Pittsburg shows comparatively little variation 

 on the west side, being usually 8 feet, but the changes in the roof are 

 abrupt. The little coal above at the top of the horizon is thoroughly 

 persistent, its blossom having been observed at many places within the 

 basin. There seems to be no trace of the Eedstone, for its place is well 

 exposed. The coal bed, Number 4, is equally persistent, but is fully 

 shown only along the railroad, where it is a double bed with from 16 to 

 30 inches of coal. It may be at the Upper Sewickley horizon, but its 

 place is uncertain. Limestone is present in large proportion and in this 

 respect the section differs greatly from that at a few miles east in the 

 Blairsville- Connellsville and west in the Lisbon Irwin basin. f 



The Lisbon-Irwin iasin. — This lies west from the Saltsburg-Fayette 

 anticline and extends westwardly to the Waynesburg fold. A small area 



•J. J. Stevenson: (K 2), pp. 134, 135, 136, 144, 146, 147, 153, 154, 155, 156, 179, 

 180, 191. The writer Is under obligation to Messrs W. Beeson, A. D. Bwlng, and J. V. 

 Thompson of Uniontown, Pennsylvania, for records of shafts and borings. 



tJ. J. Stevenson: (K 2), 272, 298, 299, 300. 



