CORRELATION OF ALLEGHENY FORMATION 71 



The Butler sandstone of I. C. White, Upper Freeport sandstone of 

 authors, is, like most of the sandstones, somewhat indefinite; but one finds 

 very frequently in the interval between the Freeport coal beds a sand- 

 stone, sometimes very thin, at others filling the whole interval. There is 

 no regularity in the occurrence of these sandstones. 



The Lower Freeport coal bed .. . In Pennsylvania, Lower Freeport, Middle 

 J. P. Lesley, 1856. Freeport, D. D' ; in Ohio, Roger and Shaft 



of Jefferson, 6a of central counties, Black, 

 Fowler, Juniper, Frank of Hocking valley, 

 Hatcher, Waterloo of Lawrence; in Ken- 

 tucky, Coal 8; in West Virginia, Lower 

 Freeport. 



This is almost as persistent in Pennsylvania, Ohio, and Kentucky as 

 the Upper Freeport, but is less frequently of economic importance. It 

 shows abrupt and extreme variations in thickness as well as quality and 

 occasionally carries on top a thick deposit of impure cannel. It yields 

 excellent coal in Jefferson county of Ohio, but in the greater part of that 

 state it is worthless. Locally it is valuable in southern Ohio, but is in- 

 significant in both Kentucky and West Virginia. 



The Lower Freeport limestone . . In Pennsylvania, Lower and Middle Free- 

 ■ H. D. Rogers. port ; in Ohio, Norris and Snowfork of 



Hocking valley ; apparently wanting in 

 Kentucky and West Virginia. 



In general features this resembles the Upper Freeport limestone. In 

 the eastern basin of Pennsylvania it extends farther north than any other 

 limestone, but its distribution throughout is very uncertain. Like the 

 Upper Freeport, it varies in purity, yielding at times fine lime, but often 

 is wholly worthless. Fossils are rare and those which do occur are 

 thought to be of fresh-water types. 



The Freeport sandstone of IT. D. Eogers is as irregular and indefinite 

 as the Butler sandstone, but in most localities a sandy shale or sandstone 

 is present within the interval between the Lower Freeport and Upper 

 Kittanning coal beds. This interval shows some interesting variations in 

 Clarion and Armstrong counties and elsewhere in western Pennsylvania. 



The Upper Kittanning coal bed. In Pennsylvania, Currie of north Butler, 

 F. Piatt, 1877. Darlington of south Butler ; rarely present 



in Ohio and Kentucky ; indefinite in West 

 Virginia. 



This is a widely persistent though very variable bed in Pennsylvania, 

 but it disappears in the western part of that state to reappear somewhat 

 rarely in Ohio. It quickly becomes indefinite in West Virginia and can 

 not be recognized with certainty in the Kentucky sections. 



