part 3] THE TRIAS OF IS^EW ZEALA^'D. 181 



and the veiy alate Spiriferina diomedea. The section was de- 

 scribed by McKay, and later b}^ Park. I confirmed the litho- 

 logical sequence as Prof. Park ^ re^^resents it, and have added in 

 JBg. 2 (p. 180) my interpretation of the zones represented after 

 ■examining the fossils collected there. 



Moor light Range. 



This • lies more or less on the westward continuation of the 

 Hokonui Hills, but the geology of the district is very little known. 

 A considerable series of Triassic rocks is probably present there. 

 In the Greological Surve}^ Collection from this locality I identified the 

 following forms: Pseudomonotis riclimondiana Zittel, and a large 

 flat form like Ps. ocliotica Teller, var. densistriata, HaloreUa sp., 

 and a small bivalve. 



y. Pal^eon^tology. 



CEPHALOPODA. 



The Cephalopods of the New Zealand Trias belong to the genera 

 Orthoceras, Clydonautilus, and Grypoceras among the Nautilids ; 

 Aulacoceras, among the Belemnoids ; and among the Ammonites, 

 Arcestes^ Cladiscites, Plnacoceras, and Discopliylliies. The last 

 is the only ammonite sufficient^ well preserved to afford any 

 Teal zonal information. No cephalopods have been found in the 

 Kaihiku Beds, and the Trias of New Zealand shares with that 

 of New Caledonia and the Malay Archipelago the absence of 

 .ammonites of the Ceratitic type, or of the profuse Upper Triassic 

 iimmonite fauna which occurs in Western America and in the 

 Himalayas. 



Orthoceras sp. (PL XYII, fig. 6.) 



Surface of the shell smooth ; growth-lines straight, not sinuous. 

 The septa are rather strongly convex towards the apex, and the 

 «iphuncle is slightly excentric. Length originally i= about 40 mm. ; 

 •diameter of aperture=:6 mm. ; and length of living chambers about 

 11 mm. The aperture of the latter is preserved, and is circular in 

 outline, quite horizontal ; the rim is slightly thickened. In the 

 angle of emergence and other features it resembles O. friodicum 

 Mojsisovics. 



Locality and horizon. — The only locality that I know where 

 this dwarfed Orthoceras occurs is Bed c, Otamita, Hokonui Hills, 

 Oarnic. Previous records of Orflwceras seem to have been based 

 on parts of the phragmocones of large Atractitid belemnites. 



■Grtpoceras of. MESODTSCUM Hauer. 



1902 E. von Mojsisovics, ' Cephalopoden dev Hallstatter Kalke ' vol. i, Supplein. 



p. 229. 

 1910. G, B(i3hm, Ceiitralblatt f. Min. &c. p. 635. 



The name of Nautilus mesodiscus appears in Hector's list of 



1 Bibliography, 39, p. 382 & pi. xxix. 

 <^. J. a. S. No. 291. Q 



