CRETACEOUS FORMATION. Ill 



LAUDERDALE COUNTY. 



The Tuscaloosa formation, which carries the clay 

 deposit^, covers only the western half of Lauderdale, 

 the Subcarboniferous rocks forming the surface over 

 the eastern half. The clays are white, red and mot- 

 tled, and generally quite plastic. Mr. McCalley gives 

 some notes concerning them. 



At the Tan- Yard Spring, in the N. E. J of the 

 N. W. J of S. 24, T. 1, E. 14 W., there is the following 

 section : 



Section at Tan Yard Spring, Lauderdale Co. 



Ferruginous crusts 1 foot 



Clay, somewhat stained with iron, unctious and 



plastic when wet 5 feet 



This clay has been analyzed by Dr. Pickel, of the 

 University of Alabama, wit'h the following results : 



Analysis of Clay, Tan Yard Spring, Lauderdale Co. 



Silica 59.65 



Aumina 27.04 



Ferric oxide 4.75 



In the gullies, near the top of the divide between 

 Brush and Bluff creeks, in the southwest of the 

 northeast of S. 30, T. 1, E. 13 W., there are deposits 

 of white unctuous clay from seven to eight feet thick.* 



Dr. Little's notes supply some additional informa- 

 tion about! the clays of this county. Mr. Wm. J. 

 Beckwith has a clay deposit four and one-half miles 

 from Wright's postoffice, on Brush Creek. It is 

 upon a high hill, and is five or six feet in thickness. 

 The clay is of a light yellow color, and is firm, fine 

 grained and smooth. It has been shipped north and 



*Valley Regions, Part I, page 105. 



