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



farther west. It contains the same laminated clays with cross- 

 bedding and at the bottom the gray clayey sands of the pre- 

 ceding cut are seen. They were here examined and found to 

 contain extremely friable casts of small bivalves, apparently 

 marine. Near the top of the laminated clays there is a streak 

 of kaolin. — This whole material of about twenty feet thickness is 

 overlaid by a strip of limestone containing Pecten Poulsoni, Or- 

 bitoides, etc. A dip in this cut is not apparent. Going farther 

 toward Brandon no sure Grand Gulf strata were seen, but out- 

 crops of limestone occur at two or three points at the same 

 height with, or somewhat higher than the railroad track. Ap- 

 proaching Brandon and about half a mile from the station ma- 

 rine strata of about fifteen feet thickness are seen. They consist 

 of sands overlaid and underlaid by ledges of limestone, all the 

 beds containing Pecten Poulsoni and Orbitoides. The sands are 

 sometimes clayey and at one place there are among them strati- 

 fied clays of a few feet thickness which are . not laminated, 

 and contain on the planes of stratification shells and shell detri- 

 tus. At Brandon station the limestone and patches of the 

 sands are seen ; and going west of the station hard limestone 

 ledges, alternating with softer material, containing Pecten and 

 Orbitoides occur as far as two miles west from Brandon. 



The relation of the heights of all the above-mentioned cuts 

 is as follows: The railroad track rises from the point two miles 

 west of Brandon toward Brandon, continues to rise to the point 

 where the contact of the Grand Gulf and marine limestone cmu 

 be seen (about four miles east of Brandon); continues farther 

 to rise for some distance in the Grand Gulf region and then 

 falls down toward Pelahatchee. 



Eecapitulating these observations : Between Pelahatchee 

 and Brandon the railroad cuts through, for a length of five 

 miles, a belt of Grand Gulf strata, which are situated at a higher 

 level than the marine strata west of it and which are either 

 nearly horizontal or strongly dipping west. The Marine Ter- 

 tiary of Brandon rises toward these Grand Gulf strata, and at 

 the point where the two formations meet the marine limestone 

 has a thickness of only two feet and overlies the Grand Gulf 

 clays. 



Those geologists who object to the conclusion from this that 

 the Grand Gulf is older than the Marine Tertiary have the 

 choice between two hypotheses. They can either consider this 

 whole region of laminated clays, lignite, etc., with this peculiar 

 dip, as not belonging to the Grand Gnlf formation, or they can 

 consider all these exposures as Grand Gulf with the only ex- 

 ception of that one where the orbitoidic limestone is seen on 

 the top. After a careful examination of this region I am una- 

 ble to share in either of these hypotheses. 



