250 GEOLOGY OF ILLINOIS. 



mentioned, which is evidently local. In the outcrop of about two hundred 

 yards, there are great variations, from the very compact clinking stone, with 

 fish remains and large valves of Productus costatus, to an impure, concretionary, 

 almost granular limestone, crowded with generally quite small fossils. Among 

 these we find Spirifer cameratus, S. Uneatus, Spiriferina Kentuckensis, Athyris sub- 

 tilita, Terebraiula bovidens, Orthis carbonaria, Productus longisplnus, Waldheimia 

 (OryptacantMa) compacta, Retzia punctilifera? Nucula, Bellerophon, Loxonema, Ifa- 

 ticopsis, Fusulna cylindirica, etc. 



At Rock Ford, as previously stated, this bed was found to be about ninety- 

 five feet above the Danville coal seam, No. 27 of the general section. But this 

 distance is far from constant. My estimate of it on the Little Vermilion, where 

 the broken condition of the section rendered connected measurements impossi- 

 ble, was not far from eighty feet; while, in the shaft at Catlin, as I am informed 

 by Mr. John Faulds, of that place, one hundred and thirty feet of sandy and 

 argillaceous shale were passed through above the coal, without any intercalated 

 bed of limestone. 



This coal-seam appears above the level of the river, near the east line of 

 township 19 north, range 13 west ; but owing to the local undulations before 

 mentioned, it dips, rises and dips again, two or three times before making its 

 final emergence a short distance below the mouth of Middle Fork. Up that 

 stream, also, we find the coal in or not far below the bed for about two miles, 

 to near the north line of section 8, township 19 north, range 12 west, where a 

 sudden dip carries it below the level, and brings in the upper beds to the top 

 of No. 16, which, on Makemson's branch, in the west half of section 5, con- 

 tains a heavy bed of very solid ferruginous sandstone, which appears well fitted 

 for building purposes, though no quarry has been opened. Still ascending the 

 stream, we find the rocks rising, somewhat; but, at the last rock exposure, on 

 Mr. Cox's land, in section 32, township 20 north, range 12 west, the coal is 

 probably still from forty to fifty feet below the water level. Above this point, 

 we come upon the heavy beds of Drift clay and gravel which cover the north 

 part of the county so deeply as to render the exact location of the underlying 

 rocks impossible, except by boring. 



The so-called " Danville " seam of coal, No. 27 of the section, is apparently 

 equivalent to that which is numbered " 6 " in the general section of the coals 

 of the Illinois valley (see 111. Rep., iii., p. 6) ; but, as the numbering there 

 adopted will not accommodate all of the seams which have a well-defined level 

 in the field now under consideration, I am compelled to adopt, provisionally, 

 another set of numbers for the coals of the Wabash valley. I regret that the 

 impossibility of determining, at the present time, the number and constancy of 

 the seams near the base of the series, east of the Wabash, has thus far pre- 

 vented the adoption of a numbering which may be considered permanent. The 



