70 GEOLOGY OF ILLINOIS. 



identical with those found in the clay iron band at the base of No. 5. 

 Local patches of sandstone and conglomerate in lenticular masses a 

 foot or more in thickness couie in at two or three points immediately 

 above the black shales, and where this occurs the shales are compressed 

 into something less than one-half their normal thickuess. At the upper 

 end of this exposure the calcareo-bituminous shale No. 7 is replaced by 

 three or four inches of blue clay shale. The thin-bedded sandstones 

 and sandy shales in the river bed contain Catamites, and fragments of 

 other coal plants, sometimes inclosed in iron concretions similar to 

 those noticed in the river bed at Mt. Carmel. The'ferruginous band at 

 the base of the blue shale No. 5 of the foregoing section contains many 

 fine fossil shells in a good state of preservation, and the locality has 

 become somewhat noted on this account. The species to be found here 

 include the following: Nautilus occidentalism If. globatus ? Cyrtoceras cur- 

 tum, Dentalium obsoletum, Pleurotomaria tabulata, P. splicerulata, P. 

 GrayviUensis, Macrocheilus inhabilis, Ianthinqpsis tumida, Euomphalus 

 subrugosus, Nucula ventricosa, AstarteUa vera, Leda bella rugosa, Lima 

 retifera, Orthis carbonaria, and Lophophyllum proliferum. This is the 

 same group of fossils found on Raccoon creek near the north line of 

 Edwards county, at Lawrenceville in Lawrence county, and on Lamotte 

 creek near Palestine landing, showing that the Wabash river, from the 

 latter point to Grayville, continues on nearly the same geological level. 



The exposure in the Gray vjlle bluff affords an interesting exhibition 

 of the variable character of the beds occurring at this horizon, and if 

 the upper and lower extremities of this outcrop were only to be seen as 

 separate exposures their identity might not be suspected. At the upper 

 end of the hill a seam of pyritifei'ous shale from one to three inches 

 thick is all that separates the black laminated shales, while at the lower 

 end they are separated by about three feet of calcareous shale aud shaly 

 bituminous limestone. Fossils are abundant at the upper end of the 

 exposure in clay iron ore in the lower part of No. 5 of the section, while 

 three hundred yards below neither the iron stones nor the fossils they 

 inclose cau be found. Hence the difficulty of constructing a connected 

 section in the Upper Coal Measures from the examination of isolated 

 outcrops, which are the only exposures of the strata to be found in this 

 portion of the State. 



On the Little TVabash at the ford six miles west of Grayville, on sec. 

 21,-T. 3 S., E. 10 E., the bluff consists of sandstone and sandy shale, 

 inclosing a bituminous shale and thin coal. The section here is as fol- 

 lows : 



Feet. In. 



Evenly "bedded sandstone and sandy shale 30 to 40 



Bituminous shale and thin coal 1 ti 



Clay shale 5 to 8 



ilassive sandstone, partly concretionary 10 to 15 



