part 3] THE TRIAS OF ^^EW ZEALAND. 223 



a hard pebbly sandstone, which stands out as a stack in the coast- 

 section ; but specimens are very difficult to collect, the rock being 

 so hard. The Survey, however, possesses a fairlv-good specimen 

 from this locality (PL XXIV, fig. 2). Prof. P. Marshall has 

 recently sent me a piece of felspathic sandstone from South Hillend, 

 12 miles south of Benmore railway-cutting, on the south side of 

 the Hokonui Hills, Avith several casts of this shell, from which I 

 was able to make gutta-percha squeezes (fig. 1). It seems to be 

 the same bed as that in the Benmore cutting, and contains casts of 

 a large Hectoria. Khtetic. 



Kemarks. — This is the largest and latest, as well as by far the 

 most alate, of the jN'ew Zealand Triassic Spir if evince. It differs 

 from the two previously-described species in its larger size and in 

 the wings narrowing very graduallv to the points. The folds are 

 lower and more rounded, and decrease gradualh' in size, the area 

 also is broader, the ventral beak higher, and it occurs on a higher 

 horizon than tlie two previously-described forms, which are of 

 Carnic and Noric age. 



Spiriferixa ?^ELSO]S'ENsis,.sp. nov. (PL XXIY, figs. 6-8.) 



Shell alate, valves rather inflated, the anterior margin is gently 

 rounded in outline. The ventral valve has a broad median sulcus, 

 which extends to the beak, and is bounded on each side by four 

 rounded slightly-raised ribs, which decrease gradually in size. The 

 dorsal valve has a triangular median fold, which increases rapidly 

 in Avidth, and on each side of it four fainter rounded ribs Avhich 

 are continued nearly to the beak. 



The area of the ventral valve is Avide, high, and concave ; it is 

 longitudinally striate, and represents the greatest Avidth of the shell, 

 the margin of the valves converging rapidly in front of the area. 

 The delthyrium is triangular, Avide, and open, bounded on each 

 side hj dental plates, AA^hich conA'erge together iuAvards and meet 

 the median septum : this latter is visible at the bottom of the 

 open delthyrium as a thin plate projecting slightly above the line 

 of junction of the dental plates. The surface of the dental plates 

 is faintly furroAved. On both sides of the delthA^'ium another 

 slightly-sunken triangular area is separated off, and is ornamented 

 Avith faintly-impressed A^rtical furroAvs. The dorsal area is narroAv, 

 and a ' comb-tooth ' structure is seen for a short distance on each 

 side of the dorsal beak. The groAvth-lines are fairly Avell marked. 



Length = 23 mm. ; Avidth=:45 mm. 



Locality and horizon. — I collected three or four specimens 

 in the Hcdohia Beds on the Avestern slope and crest of Mount 

 Ileslington in the Nelson district. The Ncav Zealand Geological 

 Survey possesses a specimen from the same locality. Carnic. 



Remarks. — Zugmayer divides his group of Eha^tic ' Dimidiatse ' 

 into two 'form groups' (Formenkreise) : namely, the group of 

 ^piriferina uncinaia and that of 8p. stiessi, the latter including 

 only the single species. The species here described apparently 



