76 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



quite persistent in Kentucky, though almost always very thin in that part 

 of the state where correlation is possible. The distribution of these coals 

 seems to make clear, as suggested by the writer upward of thirty years 

 ago, that the coal beds were formed as fringes around the basin, some ex- 

 tending farther toward the center than the others, but all ending at a 

 comparatively short distance from the shores. Coal or carbonaceous 

 shale is reported at various depths within the central part of the basin, 

 but these deposits bear no definite relation to each other or to the recog- 

 nized horizons of the section, and in all probability they are mere accumu- 

 lations of vegetable matter drifted upon mud lumps. 



A matter of some interest which should not be overlooked is the occur- 

 rence of red shale in the upper part of the Allegheny within a little area 

 in Eitchie, Wood, and Calhoun counties of West Virginia, and Washing- 

 ton of Ohio. No trace of red shale appears elsewhere within the Alle- 

 gheny, so far as definite information is available, until one passes south- 

 westward about 100 miles into Boyd county of Kentucky, where, near 

 Cannonsburg, 18 feet of green and red shale appear between the Freeport 

 coal beds. Green shales, however, seem to be characteristic of the Cone- 

 maugh in the southern areas and in the region beyond the Kanawha. 

 Mr Campbell refers to his Braxton formation, including all deposits 

 above his Charleston sandstone, as consisting chiefly of green and red 

 shales and sandstones. In Boyd, Lawrence, and Carter counties of 

 Kentucky green shales accompany the Freeport coal beds, while in south- 

 ern Carter these green beds overlie the Lower Kittanning and in southern 

 Lawrence they overlie the Middle Kittanning. 



EAST FROM THE ALLEGHENIES 



The insignificant area known as the Broad Top coal field, embracing 

 parts of Bedford, Fulton, and Huntingdon counties of Pennsylvania, is 

 of especial interest because of variations in the coal beds and in the in- 

 tervals separating them. The following succession is a compilation of 

 measurements made by Doctor White in Huntingdon and by Stevenson 

 in Bedford and Fulton counties : 



Feet. Inches. Feet 



1. Kelly coal bed to 14 



2. Shales and sandstone 05 to 120 



. 3. Twin coal bed 1 to 6 



4. Shale and sandstone 2 to 30 



5. Barnett coal bed 1 9 to 5 



6. Shale and sandstone 8 to 50 



7. Cook coal bed 2 to 6 



8. Clay and shale 2 to 20 



to the Pottsville. 



