74 



PRESIDENT S ADDRESS — SECTION C. 



oi the Otago schists, since they pass upward (without any distinct 

 break, not into early Palaeoizoic fossiliferous beds, but into upper 

 Triassic sediments. Moreover, the miscrosccpic evidence shows 

 that great shearing and crushing has taken place in these rocks, 

 more soi than seems consistent with the idea of static meta- 

 morphism. It is very difficult, in the absence of recognisable 

 horizons, to' determine the true structure of this regio'n. The 

 overfclding of the Maitai rocks of the Nelson Province, and near 

 Mount Cook (figured by Park, 1910), and occasional over thrust- 

 faulting, (fide Morgan), suggest that recumbent folds may be •ex 

 pected in the more strongly compressed regions. While not over- 

 looking Daly's objection to the hypothesis of recumbent folding, 

 wo may indicate as worthy of testing, the concept of the Otago 



Fig. 3. Section through Mounts Haast and Haidinger, near Mt. Cook. (After Park 1910). 



schists as a series of sheet-folds, occasionally upturned and crushed, 

 and composed for the most part of the metamorphic equivalents 

 of Middle aiid Lower Triassic and Pei-miaii formations, the 

 chloritic and amphibole schists representing the Te Anau igneous 

 rocks, and the few lenses of limestone those of the Maitai series. 

 There are undeniably many difficulties in the way of accepting this 

 hypothesis, notable perhaps being the paucity of evidence of 

 asymmetry in the folding of Otago, but the difficulties in the way 

 of other interpretations seem to be at least as great. Here, also, 

 very extensive field and petrological investigation is essential to 

 progress in the study of these rocks. 



Mention should also be made here of the small area of schist 

 near the Pelorus River in the north-east of the South Island. 

 The Geological Survey considers these to. be probably of late 

 Palaeozoic agei, grouping them with the Te Anau series, and the 

 rocks of the Kakanui range in North Otago. This grouping is 

 also followed by Marshall, who, however, referred all these forma- 

 tions to his comprehensive Trias- Jura " Maitai System." Very 

 little is known of the Pelorus rocks. 



