426 



ON SPECIES OF FOSSIL PLANTS 



Beginning at its top, it has :* 



No. 10. The Grand Gulf stage, with lignitic beds, tree palms, exogenous trees, 



" 9. The Vicksburg stage, with crystalline limestone and fossil shells, 



" 8. The ferruginous rock of lied Bluff, with fossil shells, 



" 7. The Lignitic clay and Lignite of Vicksburg and N. Brandon, 



" 6. The Jackson stage, with blue marls and fossils, .... 



" 5. The Lignitic clay and Lignite of Jackson. 



" 4. The Claiborne stage in three divisions, A. calcareous with fossils. 



" 3. Lignitic clay of Clark County. 



" 2. B. Silicious Claiborne, sandstone, &c., with fossils. 



" 1. Northern Lignitic, where our fossil plants have been found, and whoso divisions are in- 

 dicated above. Thickness, ........... 







80 feet 







80 



u 







12 



a 







20 



a 







80 



u 



425 feet. 



This section is most satisfactorily completed by another given by Prof. J. Safford, in a 

 very interesting paper on the Cretaceous and Superior Formations of West Tennessee.f 

 This section, abridged like the former, indicates from the lower strata upwards. 



1st. The Coffee Sand, the inferior group of the Cretaceous in Tennessee. Under gravel and 

 ferruginous conglomerate, it has, at its base, slaty clay and yellow sand, with fragments of 

 fossil wood and leaves, 200 feet. 



2d. The Green Sand group or shell bed. The author enumerates 34 species of shells from 



this group, which contains also, though more rarely, loaves and wood, . . . . 200 to 350 feet, 



3d. The Ripley group, mostly made up of stratified sands. Twenty species are named from 



local fossiliferous beds in the upper part of the series, 400 to 500 feet. 



4th. The Porter's group, formerly included in the following, from which it is distinct only 



by its proportionally more laminated or slaty beds of clay, 2 to 300 feet. 



5th. The La Grange group, rightly considered by the author as the equivalent of Ililgard's 

 Northern Lignitic, for it contains the same species of fossil plants in strata of exactly the 

 same compound. This group occupies a belt 40 miles wide, along the State line of Ten- 

 nessee and Mississippi, between the Tennessee and the Mississippi River. Its thickness 

 is about . G00 feet. 



Oth. The Bluff lignite, apparently the equivalent of the chalk-banks of Columbus, Kentucky, 

 which I have considered, with Dr. I). Owen, as Pliocene. 



7th. The Bluff gravel, which, in Tennessee as well as at Columbus, Ky., overlies the above 

 group. It is a ferruginous chert or coarse orange sand, mixed with shells, mostly identical 

 with species of our time, and where also have been found the bones of Megahnix Jeffersonii. 



8th. The Bluff loam, a soft buff-colored clay, whose animal remains are all, but one, repre- 

 sented by species living in the water of the Mississippi Valley. 



The localities where our fossil plants have been collected, Tippah, Mississippi, La 

 Grange and Sommerville, Tennessee, are about in the middle of the belt occupied by the 



This section is abridged. The author names the essential species of fossil shells found in connection with 

 each division. 



f American Journal of Science, § 2, vol. xxxvii, page 360. 



