CARBONIFEROUS SYSTEM. 279 



be seen in the exposures on the Middle Raccoon on the 

 eastern borders of Guthrie county. These layers are inter- 

 bedded with shales ; also, sometimes, fossiliferous, giving to 

 the bed a local thickness of four to six feet. The following is 

 a list of the species known from this horizon : Crinoidal 



remains, spines of Echinoids, Discina , Productus 



cequicostatus, abundant, P. muricatus also abounds in thin local 

 bands, P. costatus, rare, P. semireticulatus, rare, Chonetes meso- 

 loba, C. mucronata, Hemipronites crassus (?) Orthis carbonaria, rare, 

 Athyris subtilita, Spirifer cameratus, rare, Spiriferina Kentuck- 

 ensis, Martinia lineatus, rare, M. planoco?ivexa, Rhynchonella 



, AUorisma , — Pleuroto mana 



Phillipsia . 



No. 32. Blue and light-colored shales, with nodular 

 bands, and sometimes slightly arenaceous; four to twelve 

 feet. The upper portion of the bed has afforded a few plant 

 remains, consisting of slender linear leaves and ferns — 

 Pecopteris, , Sphenopteris. 



No. 33. Marshall coal, two inches to two and a half feet. 

 Notwithstanding the variable thickness of this bed, some- 

 times being represented by a seam of rotten coal not more 

 than two inches thick, (Miller's branch, near Adel), it forms a 

 persistent horizon throughout the extent of the formation 

 in the State. However, the usual thickness of the bed ranges 

 from six to twelve inches, and it is only at a single locality, 

 at Marshall's coal mine, on Long branch, in Guthrie county, 

 where it attains the maximum thickness given above. The 

 quality of the coal is superior, generally being quite free 

 from jpyrite and other impurities, and wherever it is of 

 sufficient thickness and accessible, it has to great extent 

 supplied the local demand for blacksmithing purposes. 



No. 34. Blue and yellow, more or less arenaceous shales, 

 with thin indurated ferruginous bands, locally developed; 

 two to twenty feet. Its greatest development is seen on Long 

 branch, Guthrie county. In an exposure on the Middle 

 Eaccoon, at Duck's mills, Guthrie county, it replaces the 

 overlying sandstone, No. 35. At the exposures on Beaver 



