part 3] AMMONITES FROM NEW ZEALAND. 305 



This sequence is based on a list given by me l on a previous 

 occasion, but cannot be considered to be more than tentative ; for 

 a beginning is only now being made with the recognition of the 

 incompleteness of the Mesozoic record, and the former view still 

 holds sway that separate zoological provinces account for the 

 faunal differences between, for instance, the ' Volgian ' and the 

 Tithonian. For the ammonitiferous Upper Jurassic deposits here 

 discussed division into ' ages ' based on the dominant Ammonite 

 families, as practised by Mr. S. S. Buckman, seems to recommend 

 itself to the specialist ; but, whether we divide the Tithonian into 

 the three zones mentioned above, retaining those that are well- 

 known to the general geologist, or whether we change these into 

 three corresponding ages : Berriasellidan, Kossmatian, and Aulaco- 

 sphinctoidan, seems of little import. In the upper (privaseusis) 

 zone there is the maximum development of the family Berriasel- 

 lidse, with many new genera, including Parodontoceras, gen. nov., 

 for the group of Hoplites callistoides Behrendson, 2 and Prot- 

 acanthodiscus, gen. nov., for the group of Hoplites andreoei 

 Kilian. 3 The genus Berriasella itself, with Substeueroceras, 

 gen. nov. (group of Odontoceras Tcceneni Steuer 4 ), ranges into 

 the Spiticeratan age of the Infravalanginian or Upper Berriasian 

 of some writers. 



The succession of Kossmatia tenuistriata (Gray), Durangites 

 densestriatus Burckhardt, and Proniceras idoceroides Burckhardt, 

 in the zone below, is tentative, and based so far chiefly on the 

 •Mexican; sequences. The abundant Paraboliceras of the Spiti 

 Shales probably belong to this zone. 



The contiguus zone is characterized by its Perisphinctids. The 

 family Virgatitidse, with many Portlandian and Upper Kim- 

 meridgian genera, is replaced by the earliest Virgatosphinctidse, 

 notably Virgatospliinctes, simulating the Ataxioceratid genus 

 Lithacoceras of the ulmensis zone below, and the genus Aiilaco- 

 spliinctoides, which has great similarity to Torquatisphinctes of 

 the . gig as ('beckeri' and ' acantJiicus'' zones) of the Middle 

 Kimmeridgian. Toucas's 5 Diphgakalk may correspond to this 

 Aulacosphinctoidan age. 



As regards the Portlandian, Salfeld 6 quotes Pavlow's beds with 

 Ammonites bononieiisis, blalcei, devillei, and triplicatus as 

 equivalents of the Portlandian, but the identifications are probably 

 at fault. What beds of this age there may be in the Alpine- 

 Mediterranean area have not been recognized, and may contain 



1 Op. cit. (Pal. Indica, 1923). 



2 in A* Steuer, ' Argentinische Jura-Ablagerungen ' Pal. Abhandl. vol. vii 

 (1897) p; 41 (167) & pi. svii, figs. 13-15. 



3 ' Etudes Paleontologiques, &c.' in Mission d'Andalousie, Mem. Acad. Sci. 

 Paris, vol. xxx, ser. 2 (1889) p. 670 & pi. xxxii, figs. 1 «-l b. 



4 O25. supra cit. (1897) p. 45 (171) & pi. xvii, figs. 1-3. 



5 'Etude de la Faune des Couches Titnoniques de l'Ardt'che' Bull. Soc. 

 G< ; ol. France, ser. 3, vol. xviii (1890) table to p. 625. 



fl ' Die Gliederung des Oberen Jura in Nordwesteuropa ' Neues Jalirb. 

 Beilage-Band xxxvii (1914) table ii to p. 174. 



