44 GEOLOGY OF ILLINOIS. 



miles in ■width. Some portions of the latter are quite sandy, and consti 

 tute the terrace prairies between the Purgatory swamp and the Wabash. 

 The bottoms along the Embarras are heavily timbered "with all the com- 

 mon varieties of oak, hickory, ash, elm, maple, black and white walnut, 

 coffeenut, persimmon, cottonwood, sycamore, hackberry, red birch, 

 honey-locust, wild cherry, black gum, dogwood, etc. The uplands are 

 generally rolling, and were mostly originally covered with a heavy 

 growth of timber, though much of the surface has been cleared and 

 brought under cultivation since the first settlement of the county. The 

 soil on the rolling uplands is a chocolate-colored clay loam, usually very 

 productive, bringing good crops of corn, wheat, oats and grass annually. 

 With a judicious system of cultivation, and a proper rotation of crops, 

 these uplands can be easily kept up to a high standard, of fertility. 

 There are some small upland prairies along the western borders of the 

 county, the soil of which does not differ very much from that of the 

 timbered lauds adjacent thereto. 



Eichlain'D County embraces a superficial area of about three hun- 

 dred and fifty square miles, aud is bounded on the north by Jasper and 

 Crawford counties, on the east by Lawrence, on the south by Wabash, 

 Edwards and Wayne, and on the west by Wayne and Clay counties. 

 There are no large streams in the county, but some of the northern 

 affluents of the Little Wabash drain the western, and the western 

 branch of the Bon pass creek the south-eastern portion of the county. 

 The main stream of the Little Wabash also skirts the south-western 

 border of the county for the distance of about eight miles. The surface 

 of the county is generally rolling, and its area is nearly equally divided 

 into prairie and timbered land, the latter forming belts along the courses 

 of the streams from one to three miles in width, and the prairies occu- 

 pying the higher or table lands between the main water courses. The 

 elevation of the prairies above the beds of the principal streams ranges 

 from fifty to about a hundred feet. The south-eastern portion of the 

 county on the head waters of the Bonpass is quite broken, and is under- 

 laid by the heavy beds of sandstone and sandy shales intervening 

 between coals 12 and 13, which attain here a thickness of seventy to 

 eighty feet, or more. In the central and western portions the surface 

 is seldom so broken as to render it unfit for cultivation. 



The geological formations of this county comprise a moderate thick- 

 ness of drift clay, sand and gravel, that is everywhere found immedi- 

 ately beneath the soil, except in the creek valleys, where this superficial 

 material has been removed by eroding agencies ; and a series of sand- 

 stones, shales, etc., embracing an aggregate thickness of 250 to 300 feet, 

 which belongs to the upper Coal Measures, and include the horizon" of 

 three or four thin seams of coal. 



