312 GEOLOGY OF ILLINOIS. 



probably on or near the most westerly outcrop of the seam on the north 

 side of the river. 



Among the fossils common in the limestone and shales over tliis coal 

 the LophophyUum proliferum is very abundant, and is associated with 

 Astartella vera, Pleurotomaria spluvrulata, P. Grayvillemis, P. carbona-ria, 

 Bellerophon carbonaria, B. Montfortianus, B. percarinatus, B. Stevens !<i- 

 nus, Leda bella-rugosa, Nucula ventricoso, Polyphemopsis per-acuta, P. 

 nitidula, Soleniscus typicus, Loxonema rugosa, L. cerithiformis, Macro- 

 cheilus inhabilis, M. ponderosus, M. medialis, M. intercalaris, Jf. pulchella, 

 M. ventricosus, Euomphalus rugosm, Productus longispinm, P. Nebrttx- 

 censis, P. Prattenianus, Spirlfer cameratus, S. Kentuckensis, Athyris sub- 

 tilita, etc. 



The Rock creek limestone of Menard county, if it extends this lar to 

 the eastward, should outcrop on the Saugainon not very far bi low Car- 

 penter's mill, as its place in the vertical section is between coals Nos. 7 

 and 8 ; but all these Coal Measure limestones are somewhat local in 

 their development, and this bed has not been met with, so far as I 

 know, in any of the coal shafts that have been sunk in this vicinity. 



The main coal, No. 5 of the general section of the Coal Measures in 

 the central and western portions of the State, lies about one hundred 

 and seventy-five feet below coal No. 8 in the vicinity of Springfield, and 

 from two hundred to two hundred and ten feet below the general sur- 

 face level. A boring for artesian water was made at Springfield in 

 1858, and was carried down to the depth of nearly twelve hundred feet 

 without finding water that would rise to the surface, and the parties 

 having the work in charge reported no coal below the small seam thirty 

 or iorty feet below the surface, though it was evident, from the character 

 of the material brought up with the sand-pump, that they must have 

 passed through from four to five hundred feet of Coal Measure strata. 

 Subsequently, in a boring at Hewlett, a six foot seam of coal was found 

 at a depth of about two hundred feet. A shatt was immediately sunk, 

 and extensive mining operations have been carried on there to the pres- 

 ent time. The boring at Springfield not only passed through this seam, 

 but all those underlaying it, of which two or three will probably be 

 found of workable thickness, the men in charge of the work being 

 apparently entirely unconscious of the true character of the strata 

 through which their drill passed. If this work had been placed in the 

 hands of competent men, and an accurate journal of the boring kept, 

 we should now know exactly what our coal resources are, whereas 

 nothing was known in regard to the development of the lower coals, 

 except from the examinations of their outcrops along the Illinois river 

 bluffs, until borings at Jacksonville and Chapin showed the existence of 

 a seam at those points between three and four feet in thickness, which 



