CORRELATION OF ALLEGHENY FORMATION 75 



above the Brookville coal bed, and at one locality it is pure enough to be 

 used as a flux. It has not been reported southward along this outcrop, 

 but in Nicholas county one finds at the same horizon the very fossiliferous 

 Black flint which in Nicholas, Fayette, and Kanawha counties is at 1 to 15 

 feet above the Brookville coal bed. This is confined to a small area and 

 disappears quickly south from the Kanawha river. The Putnam Hill 

 limestone is often cherty in Ohio. It is possible that the Kanawha flint 

 may be equivalent to the Vanport, but its relation to the Brookville and 

 the presence of a coal bed at some places just above it render the refer- 

 ence to the Putnam Hill horizon much more probable. The occurrence 

 of this marine fauna in a very restricted area within the Kanawha dis- 

 trict is as curious as that of the Campbells Creek fauna in the Pottsville 

 within a somewhat smaller area in the same district. 



The Brookville coal bed In Pennsylvania, Cook of Broad Top, Brook- 



H. D. Rogers. ville of authors, Clermont of McKean and 



Elk, Clarion of Ligonier valley, A ; in Ohio, 

 Brookville, No. 4 ; in Kentucky, Coal 5 ; in 

 West Virginia, Upper Freeport, Lower Kit- 

 tanning, Clarion, Arden, Roaring creek, 

 Stockton. 



This is by far the most persistent coal bed in the formation. It is 

 rarely of economic importance in Pennsylvania, for though often very 

 thick it is usually a mass of alternating coal and shale, its coal high in 

 ash and sulphur. In West Virginia along the eastern outcrop it becomes 

 'very important south from the Baltimore and Ohio railroad and is the 

 only coal bed of the Allegheny on which mining operations are carried 

 on over any considerable area. It is almost as important in that state as 

 the Pittsburg is in southwest Pennsylvania. In Pennsylvania and even 

 in West Virginia it is very apt to break up into many layers of coal and 

 slate or into benches somewhat widely separated. The relations of this 

 bed have been much in doubt, and in the tentative correlation used by the 

 writer in describing the Pottsville the bed was regarded as equivalent to 

 the Lower Kittanning; but since that part of this work was published 

 additional records of borings have been secured which make the matter 

 wholly clear in the critical locality within northern West Virginia, as 

 will be seen on a later page. The Brookville seems to be the only horizon 

 at which coal was formed over any considerable area in the interior of the 

 basin, its coal having been found in Tyler, Wood, Jackson, and Cabell 

 counties of West Virginia as well as in Monroe and Washington counties 

 of Ohio, where no trace of any higher Allegheny bed appears in the rec- 

 ords of oil-well borings. At the same time it does not extend across the 

 basin, being absent in several counties east from those named. It is 



