278 GEOLOGY OP ILLINOIS. 



son and Honey creeks. Elsewhere it was not noticed, though it is probable 

 that it may be found in other parts. 



The Drift comprises a series of brown, yellow and blue clays, locally inter- 

 mingled with sand and gravel, with, in some places, thin beds of cemented 

 gravel. These deposits are spread over the entire surface of the uplands, and 

 when the Loess is present, underlie it. Bituminous coal in rounded fragments, 

 is frequently found in the Drift, and has been derived from the coal strata in 

 the adjoining region. Prom these fragments, many have been led to suppose 

 that valuable beds of coal might be found where they occur, and much time 

 and money have been wasted in searching for them. They do not furnish any 

 evidence, however, of deposits of coal in the immediate vicinity in. which they 

 occur. In section 23, township 8, range 6 west, just above the bridge, where 

 the bluff road crosses Dugout creek, considerable quantities of .drift coal has 

 been observed. It is reported that, at one time, a sufficient quantity was ob- 

 tained here to be used for blacksmithing purposes. 



The other geological formations that occur in Henderson county are the Coal 

 Measures, St. Louis group, Keokuk Limestone, Burlington Limestone, and 

 Kinderhook group. 



The Coal Measures are found only in the southeastern part of the county 

 They are represented by a few thin beds of sandstone, shales, clays, and a single 

 seam of coal, which has been found only in sections 23 and 26, township 9, 

 range 4 west. It probably belongs to coal No. 2 ? of the Illinois river section, 

 and at this point varies from one foot eight inches to two feet ten inches in 

 thickness. In the south part of section 23 it is overlaid by a yellow sandstone 

 mottled with whitish spots, which appears to be unfossiliferous. At the other 

 mine, in the northeast quarter of section 26, this sandstone contains pebbles 

 and fragments of carbonized coal plants, while in some parts of it there are 

 nodules of fossiliferous limestone. Among the fossils obtained here are Spiri- 

 fer planoconvexa, Athyris subtilita, A. Royissii, Rhynchonella Osagensis, Retzia 

 punctilifera and Terebratula bovidens. The coal rests upon a bed of fire-clay, the 

 thickness of which has not been ascertained. At this point the strata dip, at a 

 slight angle, to the southwest, while in section 23 they dip to the northeast. 



Sandstones resembling those of the Coal Measures have been found in various 

 parts of townships 8 and 9, range 4 west, also near Biggsville. Thin outliers 

 of the Coal Measure strata may also be present in other parts of the county, 

 but deeply buried beneath the Drift, and would probably afford no coal of any 

 value, if found. Where the Drift is known to rest on the Sub-carboniferous 

 limestone, the search for coal would be useless. 



St. Louis Group. Beds belonging to this group have been recognized with 

 certainty only along South Henderson creek, near Biggsville. At the time I 

 visited this place (in the spring of 1868), the creek was so high that many of 



