and Superior Formations of West Tennessee. 365 
met with, strewed over which, individuals of the species men- 
tioned, and of others, are abundant, the large shells being very 
conspicuous. ‘This formation is preéminently the shell-bed of the 
Post-paleozoic beds of West ‘Tennessee. A list of species col- 
lected is given below. It -_ contains wood and leaves, but not 
as abundantly as the Coffee 
This bed is the sortie ektindlioh of the Rotten limestone 
d Mississippi and Alabama. Its outcrop in Tennessee occupies 
the surface averaging about eight miles in width for at 
hast half way through the State. (2,2, map and section.) Fur- 
ther north it soon becomes inconspicuous, Its limits in this di- 
rection have not been satisfactorily made out. The broken lines 
mark its probable extension and termination. Its thickness is 
' known from data supplied by the well-borers. Along the west- 
ern margin of its outcrop it varies from 200 t 350 feet, the 
maximum being in the southern part of the Sta 
The list below contains the species collected io myself from 
this nie These, together with the species collected from the 
g group, were submitted to the examination of Messrs. 
Sea a Gabb. The eo — were described by them in 
the Jour. Acad. Nat. Sei., v, 2d series. In their descrip- 
tions some are referred to aoe ‘localities. The principal and 
correct localities are indicated upon the: map by small crosses, 
and will be designated in the list by letters. They are as che 
(a.) The first, at the wrt tele of the bed, in a cut of the Mem 
an 
(0.) The “Bald Hills,” ee or i miles north o i in Tennessee, 
miles northwest of Monterey, in MoNairy cou 
(¢.) A bank about 2 24 miles east of Purdy, (Pu) Tena and very near 
the top of the bed. 
es A cut in the Memphis and Charleston Railroad very _ the point 
where the railroad crosses the Mississippi and Tennessee lin 
: Platytrochus iahabtae ae and Bets, - -- - d, 
2. Corbula crassiplica, G - d, 
3, Crassatella vadosa, Ans ‘(Syn. c Ripleyana, Con. te tee a, ¢. 
4, Astarte crinulirata, ore 
5. Venilia Conradi, Mort. 4 . 
9. Arca Saffordi,Gabb, - : + * d. 
10, Nucula Cee Gabb,  - . ‘ t : d, 
1h. Cuculle Tippana, Con., - : : r ¢. 
12, Clenoides (Lima) pelagica, Mort., - * 5 a. 
4 C. reticulata, Lyell and acicrs - . 4 sé a. 
4. Pecten virgatus, Ni ilsson, - - - = a. 
15, Neithea occidentalis, Con y Cm 
- - - a,b, 
(Syn. P. quadricostata, Radiol 7a perhaps quinguecostata of Mort.) 
