SANGAMON COUNTY. 315 



Feet. In. 



Fire clay 4 



Blue shale 16 



Saudstnue 10 



Gray shale* 14 



Hard limestone 15 



Black slate j 4 



Coal No. 5 6 1 



Fire-clay '4 



Hard, gray rock 8 



267 



( '>al No. 0, which is usually from thirty-five to forty feet above Xo. 5, 

 and is generally well developed in Fultoii and Peoiia counties, has not 

 yet been found in this county of sufficient thickness to be of any eco- 

 nomic value. At Beard & Sanderson's it was found to be three feet 

 thick, on sinking: the shaft, but on drifting; on it, it soon thinned out; 

 and at the other shafts it was only a few inches in thickness. When 

 well developed, it a fiords a tine, soft, bright coal, free from pyrite, and 

 an excellent blacksmiths' coal. By referring to the report on Fultoii 

 county, in Vol. IV, p. 93, of these reports, the reader may see the con- 

 tinuation of the section from coal No. 5 to -the base of the Coal Meas- 

 ures, and the relative position and thickness of the coal seams that 

 probably underlay the main coal now worked in this county. The 

 limestone found in tumbling masses at the base of the drift clays in 

 Claiborne & Fink's shaft, near Pleasant Plains, seemed to be the same 

 rock as that outcropping on Rock creek, in Menard county, at Cogdale's 

 quarries. This limestone is a fine-grained, compact, bluish-gray rock, 

 susceptible of a fine polish, and makes a beautiful marble, of a mottled- 

 -ray color. It burns into an excellent white quicklime, and the quar- 

 ries furnish an abundant supply of material for lime-burning and for 

 building stone. This limestone is usually from 100 to 115 feet above No. 5 

 coal, though in Menard county it is only about So feet. I regard it as 

 the stratigraphical equivalent of the limestone at Lousdale's quarries, 

 in Peoria county, and the Collins viUe limestone, near Collinsville, in 

 Madison county, where it lies about 115 feet above the coal seam mined 

 at that point, which is probably Xo. 5. This limestone varies in thick- 

 in -s from five to fifteen feet, is generally even-bedded and in tolerably 

 thick layers in the lower part of the bed, and thin-bedded and nodular 

 in the upper part, where the bed is fully developed. At the outcrop of 

 this limestone about a mile south of the Xew Salem mills, in Menard 

 county, a huge cyathophylloid coral, sometimes two feet or more in 

 length, and from two to three inches in diameter, is quite common. At 

 the quarries near Collinsville. we have obtained numerous specimens of 

 the Aj-ophyllum nidis, of White and St. John, and this is the only locality 

 in the State, so far as I am aware, where this fine species has been 



