THE NAUTILUS. 



VOL. XXVIII. NOVEMBER, 1914. Is'o. 7 



THE UNIONE FAUNA OF CACHE RIVEB, WITH DESCRIPTION OF A NEW 

 FUSCONAIA FEOM ARKANSAS. 



BY H. E. WHEELER. 



Conchologists have seldom visited the "Sunken Lands" of 

 Northeastern Arkansas, and little is known of their molluscan 

 fauna. Through these vast flood-plains flow long sluggish 

 " bayous" which for most of the year develop into respectable 

 streams, but in long-continued droughts dwindle to a chain of 

 muddy hollows. Such a river is the Cache. It is formed b}' 

 the confluence of several small creeks which rise in the swamps 

 of southeastern Missouri and on the western slopes of Crowley's 

 Ridge in the upper part of Clark County, Arkansas. It flows 

 through, or forms the boundary of, eight counties in this state. 

 The only settlement on its banks is a small saw-mill hamlet, 

 and the two nearest towns along its course have less than 500 

 inhabitants each. For more than one-half of its course of more 

 than one hundred and eighty miles it parallels Black River, 

 then, maintaining a more southerly direction, it continually 

 approaches the easterly bearing course of White River, into 

 which it empties near Clarendon in Monroe County. 



Since Crowley's Ridge is the great divide between the St. 

 Francis basin and the Sunken Lands on the east, and the wide 

 valleys of the Cache and other (and more important) rivers on 

 the west, a few notes on its geologic origin and history may be 

 of interest. 



Crowley's Ridge extends from southeast Missouri in a some- 



