§36. 



NUMMULITES OF THE PYRAMIDS. 249 



sections of the inclosed shells. The Nummulites are widely 

 diffused through the ancient tertiary deposits, and form* 

 entire chains of calcareous hills. They constitute immense 

 beds in the Alps and Pyrenees, and are not confined to the 

 tertiary, but occur also in some of the secondary formations. 

 The blue clay at Bracklesham and Stubbington, and the 

 calcareous sandstone of Emsworth and Bognor, in Sussex, 

 abound in Nummulites. 



In North America, the eocene limestone of Suggsville, 

 which forms a range of hills 300 feet in height, is entirely 

 composed of lenticular bodies, supposed to be related to 

 this genus.* In some parts of France, beds of nummulitic 

 limestone of great extent and thickness occur, and are 

 referable either to the lowermost group of the tertiary 

 formations, or the uppermost of the cretaceous. 



35. Rotalije — Many of the foraminifera have cham- 

 bered shells, so like that of the Nautilus, that but for their 

 perforated surface, they might be taken for embryotic 

 cephalopoda. The animals of these polythalamia (many- 

 chambered shells), have, however, no relation whatever to 

 the nautilus, but are of a very simple structure, as we shall 

 explain in the next lecture, when treating of the Rotaliae 

 of the chalk. These animalcules swarm in many of the 

 tertiary strata ; in the annexed sketch (Lign. 42) are 

 shown two specimens adhering to a very characteristic 

 shell (Vermetus) of the Bognor sandstone. The marine 

 sands of the Paris basin are, in some localities, so full of 

 microscopic forms, that a cubic inch of the mass contains 

 upwards of sixty thousand foraminifera. f 



36. Crustaceans and Fishes. — Of the higher order of 

 crustaceans, as the Crabs, Lobsters, &c, many species are 



* Nummulites Mantelli of Dr. Morton. I have not been able to 

 detect the nummulitic structure in these fossils. See Synopsis of 

 the Organic Eemains of the Cretaceous Group of North America. 

 Philadelphia, 1834. 



f Medals of Creation, vol. i. p. 221. 



