214 GASTEROPODA OF THE INFERIOR OOLITE 



N. Guisei was first described from the Chjpeus-grit of Rodborougli Hill, where 

 fragments are numerous, though well-preserved specimens are rare. North of 

 these quarries no specimens have hitherto been discovered, but south of Rodborough 

 it has been found at several localities, and always in the same part of the Ghjpeus- 

 grit, e.tj. (1) Road-side between Symonds Hall Hill and Wootton-under-Edge; 

 (2) Horton Hill (Sodbury) ; (3) Freshford, in the Avon Valley; (4) Twerton Hill, 

 near Bath ; and (5) iu the quarries about Radstock. At this latter locahty, 

 especially on Clan Down, N. Guisei occurs somewhat abundantly in the form of 

 external casts. In this case the spiral lines have been well preserved, and we thus 

 obtain an insight into the apical conditions of the shell. 



It has already been indicated in the Introduction that Clan Down is the most 

 southerly point whence specimens of the genus Nerinsea have hitherto been obtained 

 from the Inferior Oolite, and it is worthy of remark that a form in many respects 

 exceptional should be the first to reward the collector coming from the south. 



Section F. — Folds numerous, complex. 



150, NERiNiEA (Ptijgmatis) campana, sp. nov. Plate XV, figs. 2 a, 2 h. 



Description : 



Spiral angle (regular) .... 10°. 

 Height of whorl to width . . .1:1-8. 



Approximate length . . . .65 mm. 



Shell cylindro-conical, strongly turrited. Number of whorls about twenty-two, 

 very short and deeply excavated anteriorly. The sutural carina, thick and promi- 

 nent in the early stages, is sharp and even more prominent in the later ones, 

 almost overhanging the preceding whorl. Ornaments unknown. 



The section (fig. 2 b) is not perfectly clear, but the indications are those of a 

 Ptygmatis, especially the large square-headed fold in the anterior portion of the 

 outer wall. 



Relations and Distribution. — Belongs to the more conical forms of the sub- 

 genus Ptygmatis, but easily separated from all by the salience of the sutural 

 carinse. It is just possible that a specimen figured by me from the Millepore-oolite 

 of Whitwell, in Yorkshire (' Geol. Mag.,' dec. iii, vol. i, pi. iv, fig. 7), is a flattened 

 representative of this species. 



Rare in the Lincolnshire Limestone at Belmisthorpe, in company with Ptyg- 

 matis Gotteswoldias. 



