208 GEOLOGY OF ILLINOIS. 



under them, at most places examined, a bed of the usual coarse fire 

 clay. The roof of the upper seam is composed of the usual dark- 

 colored shales, clay shales, aud soapstone. The latter was noticed only 

 at certain localities, was of a clay color, greasy feel, and rather massive 

 in appearance. Between the two seams of coal outcropping about Spar- 

 land and northwest of that place, is a massive, light-colored, coarse, 

 gritty, and very soft sandstone, about thirteen feet thick. On being- 

 quarried and dried, it seasons and becomes sufficiently hard for econo- 

 mical purposes. A similar bed of sandstone outcrops higher up on the 

 hill sides, especially at some points on Tinsley's Hollow. This is above 

 the upper coal, and, in some instances, it almost forms the roof of that 

 seam. Higher still, and almost crowning these Sparland bluffs, a thin 

 outcrop of a white, hard limestone seems to lie immediately below the 

 small amount of loess and drift clays and gravels, making the bald tops 

 of the hills. It is only three or four feet in thickness, but affords a good 

 quarry rock, and is used in a few places for burning into lime, of which 

 more will be said by and by. 



The following section gives approximately the Coal Measure deposits 

 of Marshall county. The measurements were not accurately taken, and 

 all the strata mentioned will not be found at any particular locality. 

 The section is a general average of these Sparland Coal Measure out- 

 crops and bluffs. 



Section of Sparland Bluffs. 



*No. 1. Loess and drift-clay capping the bluff, not measured. 



No. 2. Thin band of -whitish limestone 4 feet. 



No. 3. Clay shale exposures partial about 50 



No. 4. Shale and sandstone 13 



No. 5. Coal. (No.7?) 3i 



No. 6. Fire clay, shales, etc., about 11 



No. 7. Light-colored, coarse-grained sandstone ] 4 



No. 8. Clay shales 5 



No. 9. Coal, with clay partings, (No. 6 ?) 3 



No. 10. Fire clay and shales, about 20 



All the coal-bearing hills west and north-west of Sparland are of ex- 

 actly similar formation, aud would present similar sections. On leaving 

 the river hills and ascending to the high upland prairies, all evidences 

 of these sections disappear, but a deep shaft in most parts of the county 

 over the upland prairies, would disclose traces of many of the strata in 

 in the above section, and in some places might develop coal seams of 

 workable thickness. 



*NoTE. From our examinations in the vicinity of Chillicothe, in Peoria county, and extending north- 

 ward to the south line of Marshall county, we have no doubt but the coal seams represented in the 

 above section are Nos. 6 and 7 of our general section of the coal seams in the Illinois Valley. A. H. W. 



