380 BRUCE WADE 



northward, where it was completed in Henderson and Carroll 

 counties and in a portion of Henry County. In 1920 or the imme- 

 diate future the Tennessee Geological Survey plaps to complete 

 Henry, Benton, and Hardin counties and map the outliers of 

 Cretaceous gravels on the uplands of Stewart, Houston, Humphreys, 

 and Dickson counties. With the field work of all these counties 

 completed information will be in hand for a complete report on the 

 Upper Cretaceous of Tennessee. 



GENERAL GEOLOGICAL RELATIONS 



The Upper Cretaceous deposits of Tennessee outcrop in a 

 wedge-shaped area which crosses the state in a nearly north and 

 south direction, and lies largely west of the Tennessee River in 

 the west-central part of the state (Fig. i). This area is about 

 sixty-seven miles wide along the southern boundary of the state, 

 but narrows to the northward until at the Kentucky line it is only 

 about fifteen miles in width. Along the southern border in Wayne, 

 Hardin, McNairy, and Hardman counties these deposits have 

 been segregated into the following lithologic units: 



f Owl Creek horizon or member 



Ripley formation McNairy sand member 



I Ferruginous clay horizon or member 

 I Coon Creek horizon or member 



Selma chalk or formation ' 



f Coffee sand and clay member 

 Eutaw formation -^ rr. , . , , 1 



\ Tombigbee sand member 



Tuscaloosa formation 



In the northern part of the state these sediments diminish very 

 greatly in thickness. The four major formational divisions may 

 be recognized but the members or subformations lose their identity 



(Fig- 2). 



THE TUSCALOOSA FORMATION 



The Tuscaloosa formation is the basal member of the Upper 

 Cretaceous series in the eastern gulf region of the Mississippi 

 embayment. In western Alabama and eastern Mississippi this 

 formation consists of irregularly bedded sands, clays, and gravels 

 having an estimated total thickness of 1,000 feet. In Professional 



