104 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



in this portion of the county, it is replaced by sandstone which is con- 

 tinuous below with the Pottsville. The Lower Kittanning coal bed, at 

 50 to 80 feet above the Vanport, is persistent throughout the county and 

 rests on a thick bed of clay which is of great economic importance. The 

 Middle Kittanning (Darlington) coal bed is at 50 to 20 feet above the 

 Lower Kittanning, the least interval being on the river one mile from the 

 state line. Near the river this bed is unimportant, but northward it 

 shows some changes which make it locally important. At one locality it 

 shows : 



Feet. Inches 



Cannel slate 6 



Cannel 12 



Coal 3 6 



The slate is rich in carbonaceous matter, one ton yielding on distillation 

 one barrel of oil ; but an enlargement of this kind is very local, thinning 

 out in each direction until only the coal is left, and possibly within a 

 short distance the whole deposit was cut away by the overlying sandstone. 

 The interval to the Lower Freeport coal bed is occupied mostly by sand- 

 stone, the continuation downward of the Freeport. Occasionally this 

 mass is interrupted by shale, and then a coal bed is shown at 15 to 20 

 feet above the Middle Kittanning, which may mark the Upper Kittan- 

 ning, which otherwise is without representative in this region. The 

 Lower Freeport coal bed is insignificant; the Upper Freeport is usually 

 double or triple, with thin partings and a thickness of about 4 feet; but 

 at one place it resembles the Middle Kittanning, having a roof of coal 

 and cannel 5 feet thick. The Freeport and Kittanning sandstones are 

 usually massive.* 



Southward from the line of Beaver, Butler, Armstrong, and Indiana 

 counties the Allegheny formation is nowhere completely above drainage 

 except along the westerly slope of Chestnut hill, in Westmoreland and. 

 Fayette and perhaps under the Fayette anticline on the Youghiogheny 

 river in Fayette ;f elsewhere to the West Virginia line it is for the most 

 part buried under the Conemaugh, and dependence must be placed upon 

 the records of oil borings. 



In Westmoreland and Fayette the Allegheny coals have been mined to 

 very slight extent, owing to proximity of the great Pittsburg coal bed, 

 and exposures in the mountain gorges are usually too indefinite to make 

 accurate measurements possible. The information contained in Steven- 

 son's reports is fragmentary and of little value. The LTpper Freeport coal 



* I. C. White: Beaver (Q), pp. 40, 42, 47, 48, 50, 110, 194, 209, 225, 233-234, 249, 

 253, 260, 265; Ohio line (Q 2), 254, 258, 260, 263. 



f M. R. Campbell : U. S. Geol. Survey folio, Masontown-Uniontown, 1903. 



