THE BYEAM CALCAREOUS MARL OF MISSISSIPPL 



81 



in a ravine 1 1 feet below the wagon bridge on 

 the east side of Waltersville. 



Section hetween Waltersville and the National Cemctc 



12. Loess 



1 1 . Coarse gravel, pebbles 2 inches in maximum 

 length, in matrix of irregularlygi-aiued sand. 

 Catahoula sandstone (?): • 



10. Fine gray laminated sand 



B)Tam marl : 



9. Lower 10 feet consists of a shell bed with 

 Scapharca lesueun, etc., at base, overlain 

 by IJ feet of brownish fossiliferous clay 

 grading upward into yellowish ferruginous, 

 glauconitic sandy marl with shells. Upper 

 part is prevailingly brown clay with 

 patches of marl, with .shells locally abun- 

 dant. Top is yellowi.sh-gray, sparingh' 

 glauconitic, ferruginous shell marl with 

 Ostren liclcsburgensis, Pecten poulsoni, etc. 



8. Gray or brown argillaceous marl and brown 

 clay with occasional plant remains asso- 

 ciated with moUusks. Shells especially 

 abundant near the top. Dentalium nns- 



sissippicnsc, recteii jiouhoni, etc 



Marianna limestone (Glendon limestone member): 



7. Grav glauconitic, somewhat indurated marl 

 with poorly preserved fossils. Nodular in 

 upper part 



6. Blue-gray or gray fossiliferous glauconitic 

 argillaceous marl with some stiff blue clay 

 at top. Lepidoqidina 



5. Gray marl, slightly indurated at top, which 

 forms a projecting ledge over Nos. 3 and '1. 

 The top is level with the floor of the bridge 

 at the south end 



4. Stiff brown clay with thin partings of marl. . 



3. Gray or yellow marl with obscure fossils; a 

 thin band of brown clay at bottom 



2. Hard pinkish-gray limestone with a little 

 glauconite and fragments of Pim\a, etc. 

 A few inches at top consists of soft lami- 

 nated gray marl with abundant Lepidn- 

 qiclina and Pecten poulsoni 



1. Gray or cream-colored sandy marl, with 

 flakes of mica and small gi'ains of glau- 

 conite. Pecten poidsoni and fragments of 

 other fossils. Thickness seen 



Feet. 

 2.5 ± 



4. .5 



4.. 5 



1..5 



The fossil species in the following list were 



obtained from the Byram marl at this locality : 



Station 7372. Road north of the National Cemetery. 



north of Vicksburg, Miss., beds 8 and 9 of section: C. W. 



Cooke, collector, Ma> 16, 1915; 



Lepidocyclina supera (Conrad). 



Archohelia mississippiensis (Conrad). 



Archohelia vicksburgensis (^'om-ad). 



ActaeocLna crassiplica (Conrad). 



Terebra tantula Conrad. 



Terebra divisura Conrad. 



Turris (Pleuroliria) cochlearis (Conrad). 



Bathytoma congesta (Conrad ). 



Surcula (Pleurofusia) Wcksburgensis (Conrad). 



Cochlespira cristata (Conrad). 



Drillia abundans (Conrad). : 



Drillia tantula (Conrad). ■ 



Scobinella caelata Conrad. 



('onus protractus Meyer. 



Conus alveatus (^oiirad. 



( )!ivella mississippiensis (Conrad"). 



Olivella aliluens Casey. 



Caricella demissa Conrad. 



Lyria mississippiensis (Conrad). 



Busycon spiniger (Com-ad). 



Latirus protractus (Conrad). 



Xancus wilsoni (Conrad). 



Phos mississippiensis (Conrad). 



Rapana n. sp. (O. B. Hopkins, collector). 



Murex mississippiensis Conrad. 



Galeodea (Sconsia) lintoa (Conrad). 



Ficus mississippiensis Conrad. 



.\porrhais lirata (Conrad). 



Architectonica trilirata (Conrad). 



Sinum mississippiense (Conrad). 



Fissuridea mississippiensis (Com'ad). 



Dentalium mi.ssissippiense Conrad. 



Scapharca lesueuri Dall. 



Ostrea vickslnu-gensis Conrad. 



Pecten poulsoni Morton. 



Corliida engonata < 'onrad . 



Protocardia diversa (Conrad). 



Pitaria (Lamelliconcha) imitabilis (Conrad). 



Macrocallista (Chionellai .sobrina (Conrad ). 



( 'rassalellites mississippiensis (Conrad i. 



Less complete exposures of the Byram marl 

 are found in the upper courses of both Mint 

 Spring Bayou and Glass Bayou at Vicksburg. 

 At Haynes Bluff, 14 miles north of Vicksburg, 

 only 8^ feet of the Byram marl is exposed. It 

 consists of yellow glauconitic sandy fossiliferous 

 marl overlain by gray calcareous clay. The 

 fossils obtained at HajTies Bluff' are listed under 

 station 7385. 



BYKAM. 



In the bank of Pearl River at Byi-am are the 

 typical expo.sures of the BjTam marl. Broad 

 ledges of indurated glauconitic marl alternat- 

 ing with softer beds of green clay rise about 10 

 feet above low-water mark. The rock is 

 abundantly fossiliferous, and most of the fossils 

 are contained in pockets of softer marl. The 

 species wliich have been obtained from these 

 beds are included in the general list. 



The marl beds and ledges of impure limestone 

 extend up and down the river from Byram for 

 several miles, but the individual exposures 

 show thicknesses so small that it is difficult to 

 determine just where to draw the line between 

 the Byram marl and the Marianna limestone. 



