155 



of separating these plates, for the purpose of increasing or dimi- 

 nishing its degree of buoyancy. The fibrous structure of the plates, 

 Fig. 1 8, appears to be rather confirmatory of its possessing this power ; 

 since, should these have been muscular fibres, their action would have 

 materially affected the size of these cavities. 



N. complanata. This fossil is smooth, round, very broad, and flat, with 

 an undulating margin. 



This species is directly known by its extreme thinness, every spiral 

 turn and every septum being perceptible even on the surface. One of 

 this species is represented Plate X. Fig. 27 ; and Plate X. Fig. 2 1 , 

 represents its longitudinal section. By an examination of this section 

 with a single lens, I could not discover any more than the upper and 

 under plate. 



Possessing a very interesting mass of nummulites, and other marine 

 bodies, which was presented by the Abbe Fortis to Mr. Strange, I made 

 it the next subject of my examination. Speaking of the fossils observed 

 whilst tracing the course of the Duare to its mouth, the Abbe says : 

 " Further on the road, in the jurisdiction of Slime, are to be seen, in great 

 quantities, various kinds of flints of different colours, and curious marbly 

 compositions of marine bodies, susceptible of a fine polish. I have some 

 specimens, that deserve a place in any museum whatever. One, in 

 particular, is an aggregate of marble, composed of lenticulares, fragments 

 of other fossil marine bodies, and white angular pebbles. Among the 

 small petrified lenticulares contained in this marble, some have their con- 

 cameratioris distinguishable on the outside. In looking, with the nakfcd 

 eye, on the superfices of this marble, one discovers a very great variety 

 of sections of the lenticulares contained in it ; and almost every particle, 

 when examined with a glass, affords something agreeable." Travels into 

 Dalmatia, by Abbe Alberto Fortis, p. 294. 



Of the flints mentioned by the Abbe, in the former part of this para- 

 graph, I possess one which is of a light yellowish colour, in which the 



