PRESTWICH BRITISH AND FOREIGN TERTIARIES. 245 



feet. 

 Greenish marl with Ostrea Bellovacina, Melanin inquinata, Cerithvum acutum, 



Cyrena cuneiformis, Slc 1 



Green clay 4 



Earthy lignite mixed with some red clay and flat pieces of iron pyrites 3^ 



Green clay 2 



White sand." 



At Pronleroy, a short distance south of Coivrel, is this section (p. 244). 

 The lower sands here commence to exhibit the marine fossils of Bracheux. 



feet. 



" Mottled grey and buff stiff clay containing petrified wood 2 



Hard greyish fissile limestone full of Chara seeds , 3^ 



Greenish marl with Ostrea Bellovacina in abundance 1 



Green sand with the same oysters 2^ 



Whitish-grey sand, with Cueullace, Crassatella sulcata, Venericardia mutti' 



costata, Turritella edita, &c 5 



Yellow sands with the same shells more numerous 8 



Chloritic sands without fossils, — the Chalk at a slight but variable depth." 



This series is extremely variable. The following is the section (p. 234) 

 at St. Sauveur, near Pont St. Maxence, one of the places where the beds 



over the lignite (but belonging to that series) contain marine shells. 



feet. 



" Superficial soil 1^ 



Yellow sand, containing an immense quantity of Ostrea Bellovacina, Ceri- 



thium mutabile, Cyrena cuneiformis, Pectunculus terebratularis, &c. ... 8^ 



Grey glauconiferous sand 3^ 



Bluish marl with lacustrine shells 3^ 



Earthy hgnite 2 



Greenish and bluish FuUer's-earth 4 



Lignite, soft Of 



Blackish shelly marl 1^ 



Lignite, harder 0§ 



Marly yellowish-white limestone, hard, fissile, and shelly 1 



Hard compact hgnite, with plants, and bones of Lophiodon, Crocodile, &c.... 4 



Blue marl with selenite 3^ 



White clay 5 



Grey glauconiferous sands, to the water-level ^^ 



These beds dip beneath the Glauconie moyenne (Graves)." 

 A well at Clermont gave the following section (p. 288) : — 



feet. 



" Sands belonging to the Glauconie moyenne 19^ 



Brown clay 6| 



Sandy marl with Cyrena, Ostrea, Cerithium, Slc H 



Earthy lignite ■, 1 



Blackish clay 1^ 



Earthy lignite 1^ 



Greenish-yellow glauconiferous sands." 



At Boulincourt, near Agnetz, the thickness and number of the beds 

 forming the lignite series varies very greatly. At Froidmont, between Cler- 

 mont and Beauvais, is this section (p. 249) : — 



feet. 

 " Yellowish clayey sand with flint-pebbles, Ostrea Bellovacina, and veins of 



white marl, — very variable 11 



Several beds of earthy lignite, separated by greyish clayey marl — very variable 3 



Bluish-grey clay 6^ 



Fine grey sand, compact — maximum thickness 13 



Earthy hgnite, containing pyritous wood and nodules of iron pyrites 2 



Marly hmestone with lacustrine fossils 0^ 



