MOOEE ABNOE-AIAL SECO>'DAET DEPOSITS. 



549 



show that their presence under such cii'cumstances is not an isolated 

 case, and that in some other districts freshwater remains occur 

 abundantly in some of our mineral veins. 



43. Proseepln'a Lyelli, spec. nov. PI. XT. figs. 3, 4. 



Shell small, smooth, discoidal, depressed : spire rather depressed ; 

 volutions about four ; the upper whorls rather convex, the body- 

 whorl flattened and more rapidly increasing ; margin obtusely an- 

 gulated ; base shghtly convex ; umbilicus large, deep, and rounded ; 

 aperture large, ciix-ular; peristome rather thick, the inner margin 

 of the outer lip with three obHque projecting teeth. 



Owing to a fragment of some foreign substance covering a part 

 of the mouth of the shell towards the umbilicus, it is not completely 

 exposed. 



Of this very interesting terrestrial shell I have discovered but a 

 single specimen. 



PiEROCHEiLOs, gen. nov. 



44. PiERocHEiLos PRiiirs, spcc. nov. PI. XIV. figs. 4, 5. 



Shell very thick, small, general contour angulated or rhomboidal; 

 spire short, depressed, and angulated ; surface of the shell smooth; 

 whorls 4-5 ; the body- whorl centrally carinated, dividing its uj)per 

 surface from a very angulated base. The carina terminates in a 

 small, triangular, wing-like boss or projection on the centre of the 

 outer lip. Aperture round ; peristome thick, circular, and entire, 

 bounded towards the columella by a shghtly raised rim ; columella 

 very thick, folded, subumbihcated, greatly extending beyond the 

 peristome, and possessing a wide but shallow sulcus towards its base. 



Of this very peculiar shell, for which I propose the above generic de- 

 signation, I possess but a single specimen. It is from the Brocastle 

 Liassic conglomerate, and is associated with the numerous species 

 of corals from my collection, described by Dr. Duncan, and the many 

 other beautiful gasteropods for which this deposit is so remarkable. 



Pleuratella, gen. nov. 



45. Pleuratella prema, spec. nov. PL XIV. figs. 1, 2, & 3. 



Shell rather small, thick, rotelHform, discoidal ; spire much de- 

 pressed; apex subacute; volutions 4-5, increasing rapidly and 

 encircling; surface of the shell C[uite smooth and without ornamen- 

 tation ; margin of the whorls convex ; aperture very large, rounded 

 or shghtly ovate ; outer hp crescent-shaped, thinnest in the centre, 

 but thickening as it passes do^vn and meets the base of the colu- 

 mella: columella short, thick, terminating below in a folding or 

 incurved boss, in the centre of which there is a distinct siilcus or 

 excavation. 



The upper surface of this shell so much resembles some of the ro- 

 telliform species of Pleurotomaria that it might readily be mistaken, 

 were its base concealed, for that genus. I possess five examples 

 of this shell, four of which are from Brocastle, the other from the 



