24 



DESCEIPTION OF A NEW SPECIES OF HELIX, 

 FOUND FOSSIL IN A CALCAREOUS SANDSTONE 

 DEPOSIT AT KENT'S GROUP, 



By Robt. M. Johnston, F.L.S. 



\nead nth May, 1880.] 



Helix Simsoniana, n.s. 



Shell solid, umbilicated, convexly depressed ; whorls, 3|y 

 rapidly increasing, ornamented above by somewhat coarse 

 wrinkled transverse striae, which become more regular as 

 they approach the nucleus ; base convex, and obsoletely irregu- 

 larly cancellated ; periphery sharply keeled ; umbilicus deep, 

 and narrowly perspective ; aperture oblique, lunately-ovate, 

 with a broad, shallow sinus at periphery, which latter is less 

 sharply keeled as it approaches aperture ; margins simj)le, 

 slightly converging, columellar margin curved, moderately 

 thickened, and slightly reflexed. 



Dia. max., 32 mil.; min., 25 mil.; height, 13 mil. Habitat :. 

 Fossil in calcareous sandstone (tertiary), Kent's Group. 



This interesting fossil is more closely allied to the existing 

 H. Launcestonensis than to any other Tasmanian form, and it 

 is nearly its equal in size. 



The fragments of rock, in which several specimens of this 

 interesting shell were found imbedded, were presented to me- 

 by Mr. A. Simson, who obtained them through Admiral 

 Harnard, from Kent's Group. The rock — a calcareous sand- 

 stone — is similar to the Helicidce sandstone of the Furneaux 

 Group. 



It would be a desirable thing if the lighthouse authorities 

 could be induced to interest themselves in obtaining a box 

 or two of the richly fossiliferous rock, in order that its 

 position may be more satisfactorily determined. I am as. 

 yet in doubt whether to class the rock with the tertiary 

 grouj^, of which the Geilston travertin is a member, or with 

 the Helicidce sandstone of the Flinders grou]). 



I made a similar appeal en a former occasion, but, I regret 

 to say, without any satisfactory result. 



