58 UNIVERSITY OF MISSOURI STUDIES 



ily remove it from the barite. After removal from the pits the 

 barite is spread out on boards or on the ground and allowed to 

 lie there in the sun for a day or so, to thoroly dry it. It is then 

 cleaned by putting it in a "rattler," a small box on rockers with a 

 perforated bottom, and by rocking it the clay is slowly knocked 

 off. The very high degree of plasticity is significant as indicat- 

 ing the presence of colloids. A part of the colloids might be fer- 

 ric oxide, judging by the color. The following are several typi- 

 cal sections taken in different parts of the area. They illustrate 

 the structure of this material very well. 



On road east of Potosi 



1. Light to dark gray soil 5 to 10 in. 



2. Buff to tan clay 6 to 18 in. 



3. Pink to light red clay 6 to 12 in. 



4. Deep, dark red clay (may contain quartz or chert) 1 to 12 ft. 



One and one-half miles north of Mineral Point 



1. Yellow soil 1 ft. 



2. Light reddish clay 1 ft. 



3. Red clay with mingled fragments of barite and 



quartz 3 ft. 



Race track diggings, one and one-half miles northwest of Potosi 



1. Gray soil 1 ft. 



2. Red clay 2 ft. 



3. Red clay and gravel (quartz and chert) 8 in. 



4. Red clay and barite 2 ft. 6 in. 



Section two m.iles northeast of Richwoods 



1. Black soil 1 ft. 



2. Yellowish clay ("mulatto") 1 ft. 



3. Red clay and gravel 1 ft. 



4. Dark red clay and barite 2 to 3 ft. 



Section in Mud Town diggings, east of Old Mines 



1. Yellowish soil 6 in. 



2. Yellow to red clay 1 ft. 



3. Dark red clay and barite 2 to 4 ft. 



