190 GEOLOGY OF ILLINOIS. 



Ft. 



1. Clay SJ* 



2. Dry saud 10 



3 . Yel low and mottled clay 3 



4. Quicksand with, "water 



Two hundred yards distant another well was dug with somewhat 

 different results, passing through 27 feet of clay to clay and gravel, 

 with a flue stream of water at the bottom. 



Near Decatur, and for three miles west and eastwardly on Sangamon 

 hills, the soil is of a light mulatto color, reddish-brown clay with a few 

 pebbles appearing near the surface. Near Decatur the growth is black 

 oak, white oak, hickory, hazel and some walnut. Near the edge of the 

 prairie the growth is principally bur oak, laurel oak, hickory, hazel, 

 plum and cherry; passing from the timber to the prairie the change is 

 rapid from the light colored and yellowish soil of the timber to the deep 

 rich black prairie soil. 



Two miles south of Decatur the soil and growth changes from that 

 of the black oak land to richer, with groves of elm, white oak, walnut, 

 hickory, sassafras, vines, chestnut oak, laurel oak and mulberry. 



Near Mfc. Zion are tracts of good land, with white oak, walnut, chest- 

 nut oak, hazel, sugar tree aud buckeye ;. the washings disclose some 

 gravel. On the hillsides are goose grass and pennyroyal. On the 

 bottoms of Big creek blue ash, white walnut, sugar tree, elm, linden, 

 with large buckeye aud bur oak trees are found. 



Pin oak and laurel oak are generally found at the edge of the prairies. 



Ou sangamou bottoms there is plenty of good timber, including bur 

 oak, red oak, black walnut, elm, linden, hackberry, buckeye, hickory, 



etc. 



Prairies. — In many places the prairies still preserve their native 

 beauty, covered with tall grass aud adorned with Flora's bright gifts, 

 among which are found the delicately beautiful Physostegia Virginiana, 

 Gerardia tenuifolia, Gentiana puberula, with the coarser plants Silphium 

 laciniatuni and S. terebinthinaceum, Liatris (2 or 3 species) Helianthus, 

 Solidago, etc. 



Stratigraphi'cal Geology. 



The geology of this county is only "surface." Except in one well, no 

 older formations than the Drift have been discovered ; at about 100 feet 

 in a well at Macon it is said solid rock was struck, which may be 

 doubted, inasmuch as large bowlders are often fouud' in the clays of 

 that vicinity. 



Alluvium. — This includes the soils and recent formations along the 

 streams. The Sangamon banks are 8 or 9 feet high and composed of 



