TO GEOLOGY. 191 
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 Lanu- 
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, “‘ce nom ayant été déja donné par M. de Lamarck 
4 une coquille de la famille des ammonites, il m’a paru convenable de 
restituer 4 ce polypier celui d’orbitolites que ce méme naturaliste lui 
avoit donné précédemment, et qui aura été probablement altéré par 
mégarde.” Desc. Geolo. des Environs de Paris, p. 398. 
