MACOUriX COUNTY. 305 



rbed by the soil and held by the impervious clays of the subsoils 

 beneath until dissipated by surface evaporation. 



The bottom lauds in this county are restricted to a narrow belt along 

 the lower course of the Alacoupiu, and some portion of this has been 

 cleared of the heavy growth of timber with which it was originally 

 covered, and brought under cultivation, and in its productive qualities 

 it ranks with the best prairie soils, especially in the growth of corn. 

 We did not find a single tract of laud of a hundred acres in extent, 

 during our explorations in this county, that would not well reward the 

 labor of the industrious husbandman, if brought under cultivation, with 

 an ample crop of some of the fruits or cereals usually cultivated in this 

 climate. 



Xatunil Mound*. There are some natural mounds in the eastern por- 

 tion of the county, among the most conspicuous of which is Coop's 

 Mound, eight miles north-east of Carlinville. This mound covers an 

 area- of several square acres, and is about sixty feet in hight above 

 the level of the adjacent prairie. It was originally covered with a 

 heavy growth of oak and hickory, and from its summit a beautiful 

 view of the surrounding country may be seen. So far as could be seen 

 from the shallow cuts made by the surface drainage, it seems to be 

 composed entirely of the common yellow gravelly clays that form the 

 upper portion of the drift in this region, and its formation is probably 

 due to the erosion of the surrounding surface after the accumulation of 

 the drift deposits. 



In closing my report on this county, I take pleasure in expressing 

 my obligations to GEO. H. HOLLIDAY, Esq., and Judge T. L. Looins, 

 for valuable information and personal assistance, and to the former 

 gentleman for several rare and valuable fossils collected by himself 

 from the Coal Measure limestone and shales of this county. Also to 

 M. UTT, of Virden, and Mr. WEIR, of Carliuville, for correct sections 

 of the coal shafts at those points. 



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