pari 3] THE TEIAS OF XEW ZEALAND. 171 



Prof. Marshall estimates the thickness of the rocks from the 

 top of the Baton-Eiver Series to the top of the Jurassic, his 

 Maitai S3^stem, at 53,200 feet. This includes the Upper Palseo- 

 zoic, Triassic, and Jurassic strata. Prof. Park reckons the thickness 

 of the Trias and Jura at 18,000 feet. When I was at Nugget 

 Point I stepped out the series of the fossiliferous Trias exposed 

 there, from the Phsetic beds northwards to the road leading to 

 the lighthouse where the Kaihiku fauna is said to occur. The 

 beds are tilted on end, and the section is clear ; but the Noric 

 Pseiidomonofis Beds are missing. I estimated the thickness at 

 well over 3000 feet. Prof. Park's diagram of the Nugget-Point 

 section includes a part of the unfossiliferous Kaihiku and all the 

 fossiliferous Trias, and the thickness is about a mile. At Kawhia 

 the Phastic alone is over 3000 feet thick. 



All rocks in New Zealand older than the Cretaceous are affected 

 by the great orogenic pressure which occurred between the upper- 

 most Jurassic and the Middle Cretaceous.^ The Trias, except on 

 tlie west side of the Hokonui Hills and immediately south of 

 Kawhia, stands everywhere nearly or quite vertical. The Jurassic 

 beds, as a rule, dip much less steeply. The schistosity of much 

 of the metamorphic rock of the Southern Alps appears to have been 

 produced during this period. Some of these metamorphic and semi- 

 metamorphic rocks are undoubtedly Mesozoic, others are Maitai or 

 pre-Maitai. Greywackes associated with the Trias pass gradually 

 into phyllites and schists. The change has been described by 

 Prof. Marshall,^ who states further that the schists pass gradual^ 

 into the gneisses of Westland. The semi-metamorphic slaty 

 argillites at Mount St. Mary, which are full of crushed and dis- 

 torted Triassic fossils of Kaihiku or Ladino-Carnic age, contain 

 secondar}^ macroscopic flakes of white mica parallel to the 

 foliation. 



^ The history of New Zealand as a land- surface dates from about the time 

 of the final break-up of Gondwanaland, and its iiphft may be connected with 

 that event. In connexion -with the age of the Maitai Series, I have shown 

 that the New Zealand area was under water during- the Permo- Carboniferous 

 Period. The Jura-Cretaceous uplift is not connected Avith the present con- 

 figuration of New Zealand, except that the rocks then hardened and meta- 

 morphosed resist weathering better, and now form the Alpine Ranges. It was 

 probably reduced to a low elevation before late Cretaceous times. No part of 

 the present New Zealand can be said with certainty to have remained land 

 during Tertiary times. The present uplift dates from the Middle or late 

 Tertiary, and was more of an epeirogenic nature accompanied by block-fracture. 

 Tertiary strata are deeply involved in faults, overthrusts, and downthrows in 

 the Alpine and other areas, but in no case are they much crushed or meta- 

 morphosed. 



2 Bibliography, 21, p. 21. 



