THE GEOLOGY OF NEW ZEALAND 5 



more recently to the Australian Permian form Aphanaia, though 

 probably both comparisons are erroneous. Fragments of this 

 shell, however, are widespread throughout the South Island of New 

 Zealand, and in default of better evidence may be used to indicate 

 the extent of Permian rocks. These are succeeded by a great 

 thickness of graywackes in which an annelid tube is almost the 

 sole indication of organic life. Jaworski considers this form indica- 

 tive of a Triassic age. It is perhaps remarkable that there are 

 no traces of plant beds known among these rocks. Glossopteris 

 does not occur in New Zealand, though a form occurring in Upper 

 Triassic and Jurassic beds was for a time doubtfully referred to 

 this genus. 



Triassic. — There is no clear evidence (beyond that mentioned 

 above) of a great break, accompanied by plu tonic intrusions, 

 between the Permian and Triassic fossiliferous strata, though this 

 has been assumed by some authorities. Probably, however, a 

 regression of the sea occurred during Middle or Lower Triassic 

 times, as in New Caledonia. The oldest fossiliferous Mesozoic 

 sediments are referred to the close of the Middle Triassic, and are 

 succeeded by fossiliferous Upper Triassic rocks, representatives 

 of the three divisions of the Alpine-Himalayan Upper Trias, 

 Carnic, Noric, and Rhaetic being recognizable, and each divisible 

 into subzones. The fauna is Tethyan, with the interesting addi- 

 tion of the circum-Pacific form P seudomonotis ochotica. In general 

 the succession of Upper Triassic faunal zones is very similar to 

 that of New Caledonia. The local absence of well-marked horizons 

 gives evidence of crust-warping during Upper Triassic times, and 

 there is a notable development of basaltic tuffs and lavas among 

 the Noric rocks. The alternation of graywackes and argilhtes, and 

 intercalation therewith of plant beds or conglomerates, indicate 

 that these sediments were formed on a continental shelf. The 

 flora of the region, which has been studied by Arber, was similar 

 to the contemporaneous Australian flora, but the total number of 

 species known in the Mesozoic rocks of New Zealand is only about 

 a quarter of those known in Australia. 



Jurassic and Early Cretaceous .—These general conditions of 

 sedimentation were maintained during the Jurassic period, in 



