10 UNIVERSITY OF MISSOURI STUDIES 



that it affected the Ozark region also is shown by the rejuve- 

 nated streams and the presence of a few patches of the Lafayette 

 gravels (a late Tertiary residual deposit). 



SOILS 



The soils are mainly residual, with smaller areas of alluvial 

 soils along the streams. Residual soils predominate thruout the 

 area, but they are especially well developed in the Richwoods 

 area, the area from Old Mines to Fertile and Blackwell, and that 

 to the east of Potosi. In these regions the relief is less than else- 

 where and it is here that most of the farming land is found. It 

 is not intended to convey the idea that residual soils are found in 

 these areas only, but that they are deeper here than elsewhere. 

 All the hills have a cover of residual soil, but much of it contains 

 so much chert and quartz that it is of little value for agricultural 

 purposes. 



Alluvial soils 



In some places the larger streams have laid down thick de- 

 posits of alluvium, altho in many places the finer silts and clays 

 form only a thin veneer over the cherty gravels below. In many 

 sections seen along Mineral Fork, Mine a Breton, Bates, and Lit- 

 tle Indian creeks there was less than a foot of soil over the 

 gravels. The alluvial soils on Big River are much thicker, and 

 are, or were, very fertile. This river flows thru the southeastern 

 Missouri lead belt, and formerly the sludge waters from the con- 

 centrating mills were allowed to flow directly into the stream. In 

 times of high water this material was deposited on the flood- 

 plain and proved to be very deleterious to the crops. A court 

 order finally forced the mining companies to stop the practice. 



The bringing of the large loads of coarse gravel down to 

 the larger streams and the consequent filling up of their channels 

 is bringing about a situation which is becoming a serious matter 

 for those who own the bottom lands. In many places stone re- 

 taining walls built 15 to 25 years ago are nearly buried in stream 

 gravels. Frequently the front of the advancing gravel bed is two 

 feet high and every flood moves it farther out on the bottom 

 lands. The advance of the gravels is not unlike tlie advance of 



