r 



144 MISSOURI BOTANICAL GARDEN. 



and there tlie first workable coal is found comparatively 

 near the surface, as at Edwardaville, where the arrange- 

 ment is as follows: 



Loess and drift clay, about 60 ft 



Broken shale 2 ft. 



Limestone 5 ft. 



Coal 2 ft. 



Hard, blue, argillaceous limestone alternating with bands 



of calcareous shale 16 ft. 



Coal (Belleville No. 1 c) 6 ft. 



In other places the coal lies 250 feet deep, Worthen,* 



describing the coal measures, says in substance: 



The coal measures in St. Clair county comprise a thick- 

 ness of about 300 feet of the lower part of the coal series^ 

 embracing the horizon of five coal seams only two of which ap- 

 pear to be of economic value at the present time. . . The 

 western boundary of the coal measures intersects the river 

 bluffs about two miles below Ccnterville station . . . and 



from 



trend 



the Okaw near Tamaroa. Northward from 

 the boundary fine intersects the bluffs, it f( 



bluffs 



Madison 

 and in i 



s. Dip is moderate 

 These beds form a 



continuous outcrop from their first appearance in the river 



* 



bluffs about IJ mile below Centerville station to the north 

 line of the county, about 1 J mile north of Caseyville. . 

 Belleville coal scam No. 1 C is the principal one worked, 

 Above this coal there is sometimes a foot or more of bitum- 

 inous shale but more friH^uently the coal is directly overlaid 

 by the limestone and also underlaid by limestone. Above 

 the limestone which forms the roof of the Belleville coal 

 we usually find bands of calcareous and sandy shales, vary- 

 ing in thickness from 10 to 20 feet and on the small creek 



terminate upward 



bed of light gray clay shalcj resembliii 

 shale contains fossils . . . and 



This clay 



♦ Worthen, loc. ciL 



