38 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I49 



was kept fresh or only slightly brackish by the great volume of river 

 water flowing into the bays. 



Even the largest bay must have been nearly fresh, for it received all 

 the drainage from the midcontinent. Into the head of the bay flowed 

 the Tennessee, the Ohio, and the Mississippi. No large streams came 

 in from the east, but the western side received the St. Francis, 

 Spring River, Strawberry River, the White, the Little Red, and the 

 Arkansas. These large streams must have kept the Morley bay nearly 

 fresh as far down as Little Rock. Later, smaller bays were only 

 slightly brackish as far south as Natchez, at which latitude the pre- 

 Pleistocene valleys were narrowed by uplands west of Harrisonburg, 

 La. South of Harrisonburg the sea water was diluted by the Ouachita, 

 Little, and Red Rivers. Clearly, lack of sea shells is no evidence that 

 the Quaternary deposits of the Mississippi Embayment did not accu- 

 mulate in tidal waters. 



