88 KEMP'S ORE DEPOSITS. 



sistent is the Johnstown ore bed, near the base of the series. There 

 are two additional beds just over the Mahoning sandstone. 



The Lower Coal Measures are the chief ore producers in all the 

 States. They furnish balls of clay ironstone in very many localities 

 in western Pennsylvania, which will be found recorded with many 

 additional references in Report MM, p. 1*74, Penn. GeoL Survey. 

 The nodules are scattered through clay and shales. The so-called 

 Ferriferous Limestone, which lies a few feet below the Lower Kit- 

 taning Coal Seam, affords in its upper portion varying thicknesses 

 of carbonate ore, known as " buhrstone ore," which is altered in 

 large part to limonite. Some little carbonate ore was found in 

 the early days in the anthracite measures of eastern Pennsylvania. 

 Several beds of the same occur in the Great Conglomerate and 

 its underlying (Mauch Chunk) shales. They are chiefly developed 

 in southwestern Pennsylvania (Report KK), and may form either 

 entire beds or disseminated nodules. The limonites of the Mar- 

 cellus stage that pass into carbonate in depth in Perry and the 

 neighboring counties have already been mentioned under Example 

 2. In West Virginia both Upper and Lower Measures afford the 

 ore. From the latter black-band is extensively mined on Davis 

 Creek, near Charleston. 1 



2.01.31. In Ohio a number of nodular deposits are known, but 

 practically no ore is produced above the Mahoning sandstone of 

 the Lower Coal Measures. Below this sandstone the ores are ex- 

 tensively developed. They extend up and down the eastern part 

 of the State and are both black-band and clay ironstone. Orton 

 identifies twelve different and well-marked horizons distributed 

 through the Lower Measures. He distinguishes the stratified ores 

 mostly black-band, and the concretionary ores, including kidney 

 ores, block ores, and limestone ores. 2 



2.01.32. The general distribution of the iron ores of Kentucky 

 has already been outlined under Example 2. The Hanging Rock 

 region is a southern prolongation of the Ohio district of the same 

 geological horizon. P. X. Moore has classified the local ores as 

 limestone ores which are associated with limestone, block ores, and 

 kidney ores. The last two names refer to the fracture or shape of 



1 M. F. Maury and W. M. Fontaine, Resources of West Virginia, 1876, 

 p. 247. 



8 Geol. of Ohio, V, p. 378, and supplemental report on the Hanging 

 Rock region in Vol. III. 



