130 GEOLOGY OF ILLINOIS. 



Shoal creek the soil is rather thin, with a growth of black-jack and 

 post oak ; but further out on the prairie it becomes better. On the 

 east side of Shoal creek, between the forks, near the edge of the prairie, 

 there are some wet pin-oak flats blending into flat prairies. 



Near East Fork the hills are lower than those of Shoal creek. Near 

 the stream there is generally a good growth of white oak, black oak, 

 hazel, hickory and sassafras. This is good wheat land. Eastwardly 

 the country changes, and occasionally there are high sandy mounds, 

 often a hundred feet above the creek bottoms, which, when not too 

 sandy, are quite productive, supporting a natural growth of dog-wood, 

 sassafras, white oak, white walnut, hickory, black oak and ash, and on 

 the shaded hillsides there are many ferns. Near the east county line a 

 series of these mounds extend from the southern to the northern part, 

 generally risiug to about 50 feet above the surrounding plains, with 

 which they almost imperceptibly connect by exceedingly gentle slopes. 

 Sometimes these mounds extend into connected ridges, where we may 

 find a luxuriant growth of vines, red and white elm, cherry, hickory, 

 sassafras, ash, hazel, mulberry, black oak, red oak and local groves of 

 sugar trees. Occasionally they present a beautiful and picturesque 

 view, gently rising and falling in the distance, resembling a low range 

 of mountains. The plains are often four or five miles wide, generally 

 with a very sandy soil, inferior to that of the mounds. 



The banks of Beaver creek are low, not often more than 10 to 15 feet 

 high, and the adjacent country is generally flat. Along its margin may 

 be found pin-oak, laurel oak, persimmon, crab-apple, hazel, plum and 

 elm. 



The smaller creeks generally go dry during the summer. The beds 

 of all the streams are very sandy ; their bottoms are wide, rich and 

 heavily timbered, among which may be found, bur oak, red oak, sugar 

 tree, black walnut, white walnut, hackberry, elm, honey locust, hickory, 

 sycamore, birch and mulberry. On the hills there is an abundant 

 supply of white and black oak timber. 



Drift. — The bowlders seen in this county were all small, but among 

 them were granite, quartzite, greenstone sienite, fragments of coal and 

 fossils from the Devonian. In the western part of the county the drift 

 is not well developed, but is best seen near Greenville. At the bridge 

 on East Fork, three miles north-east of Greenville, fragments of coal 

 were found, which was a sufficient bait to the inexperienced to induce 

 searching for more coal in the drift deposits. A shaft was sunk 87 feet 

 to rock, when the water broke in and checked ^auy further work. The 

 upper ten feet passed through was yellow clay ; below it blue clay 

 extending to the bottom, becoming darker as they descended; at 25 feet 

 a large lump of coal was found, and wood at 20 feet from the surface. 

 The creek bank here shows : 



