18 Tuscaloosa Formation [216 



THE DELTA CHARACTER OF THE TUSCALOOSA 

 FORMATION 



BY EDWARD W. BERRY 



During the enormous interval of time represented by ma- 

 rine sediments in other parts of the world of late Carboni- 

 ferous, Permian, Triassic, Jurassic and Lower Cretaceous 

 ages the southern Appalachian region was above sea level. 

 Physiographically the southern half of this region is segre- 

 gated at the present time into the Piedmont Plateau, the 

 Appalachian Mountains (which die out in northwestern 

 Georgia), the Appalachian Valley, the Cumberland Plateau, 

 and the Interior Lowlands. Its area south of the Ohio Eiver 

 is over 160,000 square miles, and the actual area of this land 

 mass during the interval from the Carboniferous to the Upper 

 Cretaceous must have been very much greater than this, since 

 nowhere along the margins of this massif have marine sedi- 

 ments of these ages been deposited near enough to its present 

 limits to be reached by deep borings near the margin of the 

 present Coastal plain. 



The region of the southern Appalachians is one that has 

 long interested physiographers. Hayes and Campbell, the 

 chief contributors, 1 have recognized three base levels or 

 peneplains which they term in the order of their ages the 

 Cumberland, the Highland Rim and the Coosa. They con- 

 sider that the original Tennesee River, which they term the 

 Appalachian Eiver, flowed southwestward by way of the valley 

 of the Coosa Eiver throughout the Upper Cretaceous and the 

 major portion of the Tertiary until it was diverted by stream 

 capture due to the working back across Walden Eidge of a 

 stream in the Sequatchie valley to the west of that ridge. 



1 Hayes, C. W. and Campbell, M. R., "The Geomorphology of the 

 Southern Appalachians," Natl. Geographic Magazine, vol. 6, pp. 63- 

 126, 1894; Hayes, C. W., "The Physiography of the Chattanooga 

 District," U. S. Geol. Survey, 19th Ann. Rept., Ft. 2, pp. 1-58. 1899. 



