﻿24 0. Meyer — Tertiary and Grand Gulf of Mississippi. 



cally immediately below the Claiborne profile and the paleon* 

 tological evidence points to the same result and shows it to be 

 parallel with the strata in Lisbon, Ala. After this position is 

 determined it will be of interest in regard to the age of the 

 Jacksonian to notice that the following species of this fauna 

 occur in Jackson and are not known from the Claiborne sand : 

 Area aspera C, Leda multilineata C, Pecten scintillatus C, 

 Mitra pactilis C. var. dumosa C, Distortrix septemdentata Gabb, 

 Solarium bellaslriatum C, Flabellum Wailesii C. ; and the fol- 

 lowing species are known only from the Vicksburgian : Corbula 

 engonata C, Chama Mississippiensis C, Caricella reticulata Aldr. 



Profile of the strata in Jackson. 



The profile of the strata near Jackson, taken by Mr. Aldrich 

 and myself at various points, is as follows: 



(f) Clay ; blue below, lighter above, containing a large 

 number of small bivalves, Kelliella f, Corbula, Leda 

 and crab-claws. The shells are either very thin and 

 soft or entirely dissolved, leaving only a few impres- 

 sions _ 20-25 feet 



(e) Glauconitic marl, varying in distinctness, containing 

 Pecten, various Bryozoa and corals, concretion-like 

 Madrepora (nigger-heads), all in abundance, and in 

 addition to them some Jacksonian fossils, about 2 feet 



(d) Jacksonian shell marl. Yellowish; or yellowish above 

 and blue below. At one point this subdivision of this 

 stratum is marked by a layer of Rostellaria in great 

 quantity 10-15 feet 



(e) Dark lignitic clay, without fossils at some points, but 

 at others containing pockets of green sand full of 

 Jacksonian fossils, bivalves numerous about 5 feet 



(b) Earthy lignite 20 inches 



(a) Gray sandy micaceous clay . ... 



It will be seen that this profile differs from a profile given 

 by Mr. D. W. Langdon* in that he puts strata "e" and "/" 

 together. About a mile south of Jackson clays occur, which 

 may be or may not be identical with the clays in u f." Mr. 

 Langdon observes clays on the river south of Jackson only a 

 few feet above the water, but not far from the river clays are 

 to be found at heights of more than fifty feet above the river 

 level. I have little doubt that the lignitic, non-fossiliferous 

 stratum with very strong dip between Jackson and Byram will 

 be found on examination underlying the Jacksonian as well as 

 the Vicksburgian. 



* This Journal, xxxi, p. 202, 1886. 



