The Nautilus 



Vol. XXXI. APRIL, 1918. No. 4 



THE MOLLUSCA OF CLARK COUNTY, ARKANSAS. 



BY REV. H. E. WHEELER, CONWAY, ARK. 



Clark County lies in the south-central portion of the state of 

 Arkansas and has an area of 875 square miles and a popula- 

 tion of about 25,000. About one-third of the county — the 

 southeastern section — is of tertiary and quartern ary age. The 

 northwestern third of the county forms a part of the southern 

 exposure of a vast carboniferous area in the state which is gen- 

 erally referred to the Mississippian sub-division, and consists of 

 non-coalbearing sandstones and shales lying above the Bates- 

 ville sandstones. Between these formations lies a wedge-shaped 

 section of cretaceous marls and clays, which form the eastern 

 boundary of these limited rocks in the state. The alluvial 

 lowlands of southeastern Arkansas are developing a prosperous 

 agriculture, cotton and corn being naturally the most prolific 

 crops, but rice is now being successfully cultivated. The 

 county does not extend into the mountainous paleozoic region, 

 and hence cannot boast any elevations of consequence. 



The general course of the streams in the county is from 

 northwest to southeast. The Antoine and Little Missouri rivers 

 form the western and southern boundaries of the county, while 

 the Caddo river crosses the county along its northern boundary, 

 emptying into the Ouachita river some five miles above Arka- 

 delphia. The latter river rises in the mountains of Polk County 

 and throughout its tortuous course of several hundred miles is 

 one of the most beautiful watercourses in the entire southwest. 

 It passes through the eastern extension of the county, but con- 



