204 D. W. Langdon — Tertiary of 



4. Highly fossilifercms decomposed greensand, the grains 



of quartz small, — fossils mainly casts and showing a 

 preponderance of bivalves — Pecten Poidsoni Mort., 

 Orbitoides Mantelli Mort., very well preserved — 

 Conus sauridens Con., Cardium Vicksburgense Con., 

 and Puccinujn Mississippiensis Con., as casts 4 feet. 



5. White limestone with Orbitoides Mantelli Mort. Show- 



ing to water's edge about 200 yards farther down 



stream where it is about 12 feet thick 8 feet. 



Talus obscuring face at this point : 6 feet. 



The appearance of the limestone at this point resembles more 

 closely that at St. Stephens in Alabama than any I have yet 

 seen in Mississippi. A half mile below we have 



Section 4. 



1. White limestone containing a few greensand grains 



and occasionally an 0. Mantelli Mort. 4 feet. 



2. Decomposed greensand indurated and breaking off in 



great blocks. Contains Orbitoides Mantelli Mort., 

 Pecten Poulsoni Mort., and numbers of casts. 

 Rather large quartz grains disseminated through the 

 bed 4 feet. 



3. Blue glauconitic, sandy marl, containing Pecten Poul- 



soni Mort., Discoflustrellaria Bouei (G. and H.), Tur- 

 binolia pharetra Lea, and two species of Madrepora. 4 feet. 



From this point down to Byram Station the strata are ex- 

 posed continuously either on one bank or the other, so that the 

 connection can be easily kept in sight. Half a mile below 

 the last section the strata are exposed in a bluff half a mile 

 long and running almost due south, thus affording an excellent 

 opportunity for estimating the dip. For this purpose two hard 

 ledges of Orbitoidal limestone five feet above the water were 

 selected, and in three hundred yards they passed below the 

 river level. Just around a bend, the river cuts across the 

 strike, and, at this point, No. 2 of my section 3 has sunk 

 nearly to the water's edge, which, as this point is three or four 

 miles west of where the section 3 was made, shows a westerly 

 inclination of six or seven feet to the mile. The resultant of 

 these two dips shows a southwesterly dip. At Byram Station 

 on the Illinois Central Eailroad, ten miles from Jackson, the 

 following section is exposed : 



Section 5. 



Surface soil 15 feet. 



1. Reddish marl, containing a few grains of glauconite 

 and numbers of Pecten Poulsoni Mort., and Orbitoides 

 Mantelli Mort. 2 feet. 



