160 
FOSSILS OF THE MARL. 
bank on the estate of the Rev. J. Constable, at 
Middleham, near Lewes, and is figured by Mr. 
Sowerby, Min. Conch, tab. 74. 
FOSSILS FROM HAMSEY. 
1. Baculites obliquatus. 2. Scaphites striatus. 3. Karaites intermedius. 
The bivalves of the chalk marl need not detain 
us long: a very characteristic shell is a large pecten, 
P. Beaveri. There are also species of plicatula 
and carditay which do not occur in the other divi- 
sions of the chalk. 
4 . FIRESTONE, OR MERSTHAM BEDS. 
The chalk marl rests upon an arenaceo-argilla- 
ceous deposit of a greyish green colour, composed 
of marl and grains of silicate of iron* ; in some 
* The green particles of the firestone (^Glauconie crayeuse) of Havre 
have been analysed by M. Berthier, who found them to consist of 
Silica 
- 50 
Protoxide of iron 
- 21 
Alumine 
- 7 
Potash 
- 10 
Water 
- 11 
M. Brongniart names these grains, a granular chlorite of iron. — 
Gcog. Min. p. 249. 
