481 
[.Marbut. 
supposes that the Mississippi River formerly flowed around to the 
west of the ridge, excavating the lowland now lying on that side 
of it, and that the Ohio River at the same time flowed along the 
eastern side of the ridge excavating a part of the present valley 
of the Mississippi, and that the two rivers united somewhere 
south of where Helena, Arkansas, now stands. Subsequently 
the Mississippi River cut through the ridge where the St. 
Fig. 1. Northern part of the Mississippi embaymeiit. 
Francois now crosses it and also where Little and Castor Rivers 
traverse it in southeastern Missom-i. Finally the Mississippi 
River abandoned this channel altogether and adopted its present 
1 Ann. i-ept. jieol. surv. Ark. for ISSit, v. 'i, p. xiv. Introduction. 
PROCEEDUNGS l;. S. N. H. VOL. XXVI. 31 M.VY, 1895. 
