TO GEOLOGY. 101 



urceolata (Lamarck). The genus has not been before 

 observed in this country, to my knowledge. 



GENUS ORBITOLITES. Lamarck. 



O. interstitia. Plate 6. Fig. 204. 



Description. Orbitolites convex and cellular above, con 

 cave, papillary and minutely porous below ; cells ovate ; 

 pores above interstitial ; pores below very numerous and 

 very minute. 



Diam. 3-20ths, Height nearly .1, of an inch. 



The segment is a magnified view. 



Observations. This is a beautiful little species, and re 

 sembles somewhat in form the Orbulites lenticulata* (Lam 

 arck). It is not, however, flat beneath. There being 

 no description of the pores, I cannot say if they differ in 

 this character. In the two specimens which I have of 

 this species, the grain of sand which occurs in the Lunu- 

 lites is not observable. They were not, however, taken to 

 pieces for examination. 



* Brogniart makes the following observations in referring to the 

 figure of this shell, &quot; ce nom ayant etc deja domie par M. de Lamarck 

 a une coquille de la famillc des ammonites, il m a paru convenable de 

 restituer a ce polypier celui d orbitolites que cc memo naturaliste lui 

 avoit donne precedemment, et qni anra ete probablement altere par 

 megarde.&quot; Desc, Geolo. des Environs de Paris, p. 398. 



