THE BARITE DEPOSITS OF MISSOURI 7 



Standing upon a bluff, or any other high point in the east- 

 ern part of the area, one can readily see the Salem Platform and 

 the Potosi Escarpment. The even crests of the ridges are a 

 feature which is striking from almost any high point in the re- 

 gion, except where the Potosi Escarpment comes into view. As 

 the surface represented by the crests of the ridges bevels the 

 edges of the slightly dipping beds, it seems clear that the present 

 drainage system has developed the mature topography from a 

 former peneplain or base-leveled surface. Evidence from other 

 parts of the state supports this view. This point will be more 

 fully discussed later. 



Drainage. — The entire area is drained by Big River except 

 a few square miles in the vicinity of Rich woods which are drain- 

 ed by Little Indian Creek. Big River forms a part of the east- 

 ern boundary of the area and also flows across it for a few miles. 

 The streams of the southern part of the region flow southeast 

 into Big River, which flows in a northeasterly direction south of 

 the area, coming just to the southern boundary near the southeast- 

 ern corner. The east-central part of the area is drained by Mill 

 Creek and its various tributaries. Mill Creek flows northeast 

 and joins Big River just south of Blackwell. The western part 

 of the area is drained by several creeks which finally unite near 

 the western border to form Mineral Fork, a large stream that 

 flows northeast across the area and joins Big River. The ex- 

 treme southwestern part is drained by the North Fork, a branch 

 of the Fourche a Renault Creek; while Mine a Breton Creek 

 with its branches, Bates Creek and Swan (locally called Swine) 

 Branch drain the west-central part of the area. Amaux Creek, 

 Mill Creek, and Old Mines Creek flow into Mineral Fork from 

 the south and Clear Creek and Rocky Branch from the north. 

 Calico Creek and Ditch Creek drain the northeastern part of the 

 area. 



While several of the streams are large, they have not devel- 

 oped flood plains of any extent. Small strips of alluvium are 

 found along only the larger streams. Rarely is the valley of the 

 Mineral Fork, for instance, more than a quarter of a mile wide, 

 and its average width is from 300 to 500 feet. Patches of allu- 

 vial plains are found on the inside of the larger bends of Big 



