340 GEOLOGY OF ILLINOIS. 



No. 2. This is the thickest bed of limestone that was found in sinking the 

 shaft. In it were, Productus lonfftspintu, P. Prattcnianus, Athyris subtilita, 

 and Platyostoma Peoricnsis. 



No. 7 contained Productus lonyispinus, Syntrielasma hemiplicata, and a coral, 

 probably a Cyathaxonia. 



No. 19. This coal corresponds with that worked at the Metamora shaft, 

 No. 14 of that section, and like that, the upper and lower portions are impure, 

 only about nine inches of the middle being good. After working this seam for 

 a short time it was abandoned, being unable to compete in the market with the 

 superior Vermilion coal brought here by the railroad. Ttiis seam is, probably, 

 No 6 of the Illinois section. A boring having been made to No. 27, and a 

 portion of it mistaken for coal, the shaft was sunk through it into No. 28. 



No. 22. This is the only limestone penetrated by the shaft below the coal. 

 Only a small piece of this limestone was obtained, but in it we recognized 

 two species of Productus, and a Chonetes. The remainder of the section, from 

 No. 28, was obtained from the journal of a boring. 



No. 24, is probably the representative of coal No. 5 of the Illinois section, 

 though this is by no means certain. No. 38 was called by the miners " Sulphur 

 rock." I was unable to learn anything further about it. 



No. 42. Coal. This is supposed to be coal No. 2 of the Illinois section, and 

 corresponds with the lower LaSalle coal. This has only been reached by 

 boring. Work has ceased at this shaft for the present, but it is reported that 

 it is to be resumed hereafter. 



Economical Geology. 



Stone for Building. The supply of this material is very limited, there being 

 but very few outcrops of rock within the limits of the county. Southwest of 

 Secor, in sections 23 and 24, township 26, range 1 west, there is an outcrop of 

 limestone. The lower part of the quarry was filled with water, so that I was 

 unable to learn upon what the limestone rests, or how thick it is, but it ap- 

 pears to be somewhere from eight to twelve feet. It is of a bluish-gray color, 

 streaked with white, and for the most part, compact. It appears to have been 

 at one time celular, and the white portions have resulted from the infiltration 

 of colorless carbonate of lime. In some portions of the strata the cavities still 

 remain, and are coated with crystals of calcite, with, occasionally, pyrite. The 

 rock contains a few fossils, among the most common of which are the following: 

 Productus longispinus, Athyris subtilita, and Cyathaxonia prolifera? These 

 quarries furnish a considerable quantity of good building stone, which, from 

 its scarcity in this vicinity, is quite valuable. The rock makes good lime, and 

 the fragments from the quarries might be utilized in this way. 



