294 
ELEMENTS OF GEOLOGY. 
are associated some forms of oyster (see Fig. 251), and other 
bivalves (Figs. 249, 250). 
Fig. 240. Fig. 241. 
Micraster cor-angumum, Galerites albogalerus, Lam. 
Leske. White chalk. White chalk. 
Fig. 242. 
Marsupites Milleri, 
Mailt. White chalk. 
Among the bivalve mollusca, no form marks the Creta¬ 
ceous era in Europe, America, and India in a more striking 
Fig. 243. 
TerebratuUna striata, 
Wahleiib. Upper 
white chalk. 
Fig. 244. 
Rhynchonella oc~ 
toplicata, Sow. 
(Var. of B. pli- 
catilis). Upper 
white chalk. 
Fig. 245. 
Magas pumila, 
Sow. Upper 
white chalk 
Fig. 246. 
Terebratula carnea, 
Sow. Upper white 
chalk. 
manner than the extinct genus Inocermnus {Catilhis of Lam.; 
see Fig. 252), the shells of which are distinguished by a 
Fig. 24T. Fig. 248. Fig. 249. Fig. 250. 
ceous. valve. Upper Lower white chalk Lima spinosa, Sow. Syii. 
white chalk. and chalk marl. Spondylus spinosus. Up- 
Maidstone. per white chalk. 
fibrous texture, and are often met with in fragments, having 
probably been extremely friable. 
Of the singular family called Hudistes by Lamarck, here¬ 
after to be mentioned as extremely characteristic of the chalk 
