OIL IN THE REELFOOT AREA. 29 



gray, or in places almost black, when wet, but which becomes 

 a light gray on drying". He gives its thickness at Jackson, 

 Tennessee, as about 175 feet, and considers this the best meas- 

 urement available. This formation shows at the surface in 

 Tennessee, in a belt from 4 to 8 miles wide, just west of the 

 Ripley area. Paris and Huntingdon stand near the western 

 border, and Henderson is on the line between this formation 

 and the Ripley. Northward, it passes on into Kentucky, and 

 southward into Mississippi. 



The Porters Creek formation is covered by the Lagrange 

 formation. According to Dr. Glenn's description, "The forma- 

 tion consists of interbedded sands, clays, and lignitic material. 

 Much the larger part is sand, which is mostly fine-grained, 

 though here and there throughout the formation beds of me- 

 dium or coarse sand or even gravel may be found. Such coarse 

 beds do not seem to be continuous over any large area". 



Regarding its thickness, Dr. Glenn says, "In the deep well 

 at Memphis, the Lagrange is 963 feet thick. The well at Dyers- 

 burg penetrated 678 feet of it and one at Hickman 750 feet 

 without in either case reaching its base. In the Jackson well, 

 near the top of the formation, its base was reached at a depth 

 of 160 feet. At Wickliffe it is 430 feet thick and at Cairo 325 

 feet." It appears that the thickness of the formation, as shown 

 in the, Memphis well, may safely be relied upon for that part 

 of the state near the Mississippi River. 



If we disregard the loess, which, with the exception of the 

 alluvial bottoms, covers an area about 30 miles wide east of 

 the Mississippi River, and the thin surface mantle known as 

 the Lafayette formation, the Lagrange formation covers the 

 surface of all that part of Tennessee west of the Porters Creek; 

 and like the Porters Creek and Ripley, it extends northward 

 into Kentucky and southward across Mississippi. 



AGGREGATE THICKNESS OF THE WEST TENNESSEE 

 EMBAYMENT FORMATIONS. 



Taking the thickness of the Eutaw sand as 275 feet; of the 

 Selma clay as 375 feet ; of the Ripley as 500 feet ; of the Porters 

 Creek as 175 feet ; and of the Lagrange as 963 feet, the total 

 thickness below the Lafayette is 2288 feet. This estimate, of 



