102 Tuscaloosa Formation [300 



THE OCCURRENCE OF THE TUSCALOOSA FORMATION 

 AS FAR NORTH AS KENTUCKY 1 



By BRUCE WADE 



The Tuscaloosa formation is the basal member of the Upper 

 Cretaceous series in the Eastern Gulf Region of the Missis- 

 sippi Embayment. In Western Alabama and Eastern Mis- 

 sissippi this formation consists of irregularly bedded sands, 

 clays, and gravels having an estimated total thickness of 1,000 

 feet. In Professional Paper 81 of the U. S. Geological Sur- 

 vey L. W. Stephenson has readjusted the nomenclature of the 

 Upper Cretaceous in this region and has defined the Tusca- 

 loosa with reference to the other formations of this series. 

 , Toward thejntorth the Tuscaloosa deposits become much 

 ,thinnef "&&& We- 'made up almost entirely of conglomerates 

 ,w<hjc.h, contain Httle*sand and clay. Professor E. W. Berry 

 hgis ; made a 'sturdy b r f this series and has found evidence in the 

 fossil plants that the clays, in the basal part of the formation 

 in the region of maximum thickness, are more ancient than 

 plant-bearing clays that occur in the conglomerates about 

 luka, in northeastern Mississippi where the formation becomes 

 much thinner. He shows that an Upper Cretaceous estuary 

 existed for a long time in Western Alabama before it trans- 

 gressed into the northern part of Mississippi and Alabama. 



Until recently the Tuscaloosa formation was thought to 

 thin out entirely in the vicinity of the Tennessee-Alabama 

 line. In 1913 H. D. Miser mapped the areal geology of the 

 Waynesboro Quadrangle of Tennessee and found that the Tus- 

 caloosa was 150 feet 2 thick and extended over a large part of 

 Wayne County. Subsequent work by the Tennessee Geologi- 



1 Published with the permission of Dr. A. H. Purdue, State Geolo- 

 gist of Tennessee. 



2 Miser, H. D., " Economic Geology of the Waynesboro Quadrangle," 

 Resources of Tennessee, 1913, vol. iv, no. 3, p. 107. 



