18 GEOLOGY OF ILLINOIS. 



At Mr. Murphy's place, near the mouth of Ash more creek, on sec. 

 20, T. 11, E. 10, a bed of shelly, chocolate-colored, impure limestone, is 

 found outcropping by the roadside at the base of the Wabash river 

 bluffs. The section seen here is as follows : 



Ft. In. 



Massive brown sandstone 30 to 40 



Brown earthy limestone 3 to 4 



Bituminous shale 4 to 6 



Coal 1 6 



Fire-clay and shale 4 



These beds are equivalent to Nos. 29 to 31 inclusive of the county 

 section, and the coal at this point is coal No. 10 of the Illinois section. 

 The limestone above the coal here contains a fine Katicopsis and a 

 Macrodon. It weathers to a rusty-brown color on exposure, but when 

 first broken the color is a chocolate-brown, mottled with dark bluish- 

 gray spots. This limestone resembles the brown arenaceous limestone 

 subsequently found two and one-half miles north of New Haven, near 

 the south line of "White county, and also in the bed of the creek at 

 Carmi, and I am inclined to believe it belongs to the same horizon, 

 though fossils are by no means as numerous in it in Clark county as at 

 the localities mentioned iu White county. If this conclusion is correct, 

 it would bring the New Haven limestone on a parallel with that num- 

 bered 33, and forming the base of the Clark county section, and they 

 agree very well both in their lithological and paleontological characters. 



Trie coal seam at Murphy's averages about 18 inches in thickness, 

 and affords a coal of fair quality. 



Tracing the bluff northeastwardly from this point, the beds rise 

 rapidly, and about half a mile from Murphy's place there is about 30 

 feet of drab-colored shales exposed beneath the limestone which is here 

 found well up iu the hill. 



At the foot of the bluff on Clear creek, near the State line, a mottled 

 brown and gray limestone 1 to 5 feet in thickuess is found, underlaid by 

 10 or 12 feet of variegated shales, which are the lowest beds seen in 

 Clark county. Extensive quarries wore opened in this limestone to 

 supply material for building the old National road, and in the debris of 

 these old quarries we obtained numerous fossils from the marly layers 

 thrown off in stripping the solid limestone beds that lay below. The 

 fossils found here comprise the following species : Athyris subtittta, 

 Retzia punctulifera, Spirifer lineatus, S. plano-convexxs, Terebratula 

 bovidens, Platyostoma Peoriense, and two or three undetermined corals. 

 The limestone is a tough, fine-grained, mottled, brown and gray rock, iu 

 tolerably heavy beds, which makes an excellent macadamizing material, 

 aud also affords a durable stone for culverts, bridge abutments and 

 foundation walls. 



