196 GEOLOGY OF ILLINOIS. 



The bluff at this place is about thirty feet high and composed of browu 

 saud and small rounded pebbles. Three-quarters of a mile up the 

 Sangamon river there is a similar marsh. 



Wells. — In the timbered land wells have to be dug deeper than on the 

 prairies and on the higher rolling prairie deeper than on the flat prairie. 

 Iu the northern part of the county plenty of water is reached at twelve 

 to twenty feet ; on high prairie north-east of Bement, fifteen to thirty 

 feet; on high prairie, near Monticello, twenty to thirty feet; in the 

 south-west, eighteen to thirty feet. 



In sec. 26, T. 16 N., It. 5 E., Mr. Love has a well ten feet deep, passing- 

 through clay to sand, but the water sunk in the sand ; a half mile west, 

 plenty of water is obtained at five feet depth. At the Monticello hotel 

 the well is fifty-five feet deep, the water generally standing at twelve 

 feet from the surface, but in the summer of 1S67 it sunk to forty seven 

 feet from the top. At Centreville a well was dug on the hillside thirty- 

 six feet deep, passing through six feet of yellow clay and sand at the 

 top, then blue clay with occasional streaks of sand and some pebbles; 

 a little quicksand near the bottom, and at the bottom a stratum of dark 

 clay and sand, with a weak stream of water. The bottom of this well 

 is near the horizon of the bottom of Sangamon river. One hundred 

 feet distant, and at an elevation of twenty feet higher, a well was dug 

 twenty-six feet deep and a good stream of water procured. 



Soil and Agriculture. — The soil may be divided into two classes, the 

 prairie and the timber. The timber is a loose, mulatto soil, producing 

 good vegetables, and for fruit and vines is said to be quicker and better 

 than the prairie, and is evidently dryer. 



The prairie consists of dark, rich, loose loam, sometimes containing a 

 little gravel; after the first sod plowing, if left thus for one season, a 

 species of Helianthus grows up very thick over it to the almost entire 

 exclusion of all other plants. 



The southern prairies, I was informed, could be plowed within two 

 days after very heavy rains. 



The prairie soil seems admirably adapted to the growth of corn, the 

 yield averaging fifty bushels and often more per acre. This is not a 

 good wheat growing county ; crops of spring wheat have been generally 

 good, but this year (1868) the yield was not a half crop. Fall wheat is 

 uncertain, but sometimes yields well, better than the spring wheat. 



