part 3] AMMONITES FROM NEW ZEALAND. 287 



elsewhere l ; further, a Jurassic Pliylloceras and a Lytoceras be- 

 longing to Prof. Marshall. 



The Liassic ammonites in the British Museum, described below, 

 belong to the genera Pliylloceras, PJiacopJiyllites, and Lytoceras 

 (TJiysauoceras). There is no detailed information available with 

 "these specimens, the matrix of which is a hard, dark-green rock, 

 exactly like that of one of the Upper Triassic Pinacoceras recorded 

 hj Dr. Trechmann, 3 or of the Hettangi'an Psiloceras. These had 

 been bestowed among Neoconiian ammonites, perhaps on account 

 of the green matrix, the Lytoceras fragment being labelled 

 ' CriocerasS 



With them was the indeterminable impression of an ammonite 

 in an unlocalized, similarly hard, compact, dark-green rock. [Two 

 additional examples of probably the same species as the indetermin- 

 able impression have, however, been received from the New Zealand 

 Geological Survey since these notes were read, and show that 

 i^he ammonite is not Triassic or Liassic, like the other specimens 

 preserved in this greenish matrix, but probably entirely new, 

 "though in ornamentation and suture-line it resembles Arcticoceras 

 ■or Simbirskites. Four examples of Upper Liassic Lactylio- 

 ceras and four more Upper Jurassic Perisphinctids mentioned 

 below, were also at the same time forwarded by the New Zealand 

 Geological Survey, and consequently it has been possible to add 

 important fresh evidence.] 



There are also in the British Museum two Oxford Clay ammo- 

 nites {Cosmoceras duncani J. Sowerby sp., Nos. 48751 a & b) in 

 iron-pyrites, having the aspect of the typical Wolvercote-Suinmer- 

 town examples. These two specimens, labelled in Dr. Henry 

 "Woodward's handwriting ' Poverty Bay, New Zealand ', were 

 •obtained from Mr. B. Isaacson in 1873 ; but the decomposing 

 pyritic condition seems to be different from that which charac- 

 terizes anything previously recorded from New Zealand. These 

 two specimens, perhaps, had better not be accepted as evidence of 

 the presence of Oxford Clay in the typical European facies, until 

 confirmed by further collecting, especially since the locality 

 Poverty Bay, according to the geological maps, lies in much 

 younger rocks. 



(2) Specific Descriptions. 



(A) Lower Lias. 



Genus Psiloceras Hyatt. 



The inclusion, in this genus, of the poorly preserved forms 

 figured in PL XII, figs. 1-4, is tentative, and they ought perhaps to 



1 ' Cretaceous Cephalopoda from Zululand ' Ann. South Afr. Mus. vol. xii 

 (1921) p. 299. A small ammonite in the Sir James Hector Collection in the 

 British Museum (C 7618), ' probably from Waipara ', may be a young Para- 

 pachyrfiscus or Scapliites, but is rather too immature for identification. 



2 _' The Trias of New Zealand ' Q. J. G. S. vol. Ixxiii (1917-18) p. 179 

 (Kaihiku Gorge). 



