64 president's address — section c. 



ment and plutoiiic intrusion.* McKay (1879, p. Iu5) was also 

 of the opinion, that an unconformity existed in North Canterbury, 

 and showed Triassic volcanic rocks lying unconformably on Maitai 

 rocks in one region, and unconformably underlain by a great 

 thickness of fossiliferous and luif ossilif erous Triassic rocks in an 

 adjacent region (suggesting faulting rather than unconformity). 

 The lower Triassic unfossiliferous greywackes are almost indis- 

 tinguishable from Maitai rocks, and are apparently the same as 

 those Park (1910) has termed the Aoraugi series, recognising them 

 as the lowest member of the Hokonui system. McKay has shown 

 that much in the Wellington Province formerly relegated to the 

 Maitai system must be placed in the lower portion of the Hokonui 

 system, and indicated that the Maitai and Hokonui rocks are in- 

 timately associated in the neighborhood of Wellington itself, but 

 described no unconformity here. Park in 1910 stated that the 

 relations between the two series were indefinite, but has recently 

 reverted to his former (1904) acceptance of Hutton's view.f 

 Marshall (1912) insisted on the complete conformity of the 

 two series, a view to which Trechmann inclines. Speightf believes 

 that there is an unconformity between the two systems, and notices 

 the inclusions of pebbles of greywacke, probably derived from the 

 Maitai rocks in the Triassic conglomerates. The writer has not 

 yet seen sufficient grounds other than the absence of the Lower 

 and Middle Triassic fauna, to support the contention that any 

 break which may be present is a very great one, though crust- 

 warping may well have occurred between Permian and Upper 

 Triassic times. That such happened during Upper Triassic times, 

 is obvious from the occurrence of a. marked zone of conglomerate, 

 and the local absence of one of the fossiliferous zones of this por- 

 tion of the succession. In the cast of New Caledonia. Piroutet 

 (1917) has grouped the Permian and Triassic rocks as a single and 

 very thick sedimentary series, without any nctewcrthy angular 

 vmconformity, but has shown that in the Middle Triassic there 

 was a regressive movement of the strand, followed by the trans- 

 gression in Upper Middle and Upper Triassic times, which is also 

 represented by a faunal transgression in New Zealand. Upper 

 Triassic strata generally lie directly upon fossilifei'ous lower Triassic 

 beds in New Caledonia. It may eventually appear that somewhat 

 similar conditions obtain in New Zealand, though the supposedly 

 Lower Triassic rocks seiem unfortunately to be all iinfos!?iliferous 

 unless the Annelid beds be cousidered Triassic, as Jaworsky urges. 



The zonal subdivision of the Lower Mesozoic rocks of the Hoko- 

 nui ranges was made by Co'X in 1877, and was extended immediate- 

 ly afterwards by McKay, and applied to the interpretation of 

 the complex Nelson district on the grounds of Hector's palseontolo- 



? It must not be overlooked that Hutton considered as in tlie Maitai Series, many 

 formations now relegated 1 1 the Aoren svstem. 



t Private communication. 



