54 . president's address — section c. 



deep-seated intrusion of dioritic magmas during regioaial pressure. 

 The similarity between seme of tlie gabbroid rocks in tlie eastern 

 portion of the crystalline complex, and those ot Orepuki, (Far- 

 quhareon 1911) and the Bluff (Wild 1912), suggest these outlying 

 igneous masses are coeval with the more basic intrusive rocks of 

 Fiordland. The norite of the Bluff is intrusive into a series of 

 homblendic rocks, the highly altered product of ancient basic 

 igneous rocks which have been referred to the Te Anau series, or 

 the lower portion of the Maitai series, and probably of later Palaeo- 

 zoic age. This correlation is strengthened though not proved by the 

 occurrence of gabbroid masses intrusive into the Permian ( ?) 

 Maitai rocks of the neighbouring Longwood and Takatimu Ranges 

 and in north- west Southland. Wei thus conclude that while so>me 

 of the crystalline complex may be^ prei-Ordovician, the bulk of it is 

 probably p'Ost-Ordovician, and some may even be Mesozcic* 



Perhaps we may class with the same series of igneous intrusions 

 the gneisses of the north-west coast of the South Island, especially 

 ill the Hokitika, Mikonui and perhaps the Reefton District studied 

 by Bell (1906), Morgan (1908, 1915) and Henderson (1917). The 

 rocks collected by these writers, which the present author -has 

 seen, consist of granites of various types and syenites, all showing 

 markedly the effects of strain, especially in the most basic hom- 

 blendic types. Bartrnm (1917) has found jDiimary epidote in a 

 granodicrite of this series. Crumpled mica-gneisses aleo' occur. 

 These apparently invade the ancient (pre-Ordovician ?) sediments 

 and basic lavas, producing amphibole and mica-schist, grading out- 

 ward into less metamorphosed types of rock. 



Bartrum (1920) has described a number of pebbles of plutonic 

 rocks in a Tertiary conglomerate near Auckland. They comprise 

 banded diorite-gneisses, cataclastic granodiorites, and dio^'ites in 

 which the amphibole is often uralitic, and also an anorthosite. 

 After examining the slides kindly sent him by Mr. Bartrum, the 

 writer was struck by the similarity between these rocks and those 

 described above from the South Island, and would tentatively class 

 the two into the same series of Palceozoic intrusions. Bartrum 

 recalls the reported occurrence of dioritic pebbles in Tertiary rocks 

 at Whangaroa, North Auckland, in the region immediately east 

 of Kawhia and again in the Gisborne district. Marshall (1918) 

 repoTts finding a diorite pebble in similar circumstances near 

 Kaipara. Pebbles of plutonic rocks have been found in the 

 " Maitai " (Permian ? or Triassic) rocks of the Wellington Pro- 

 vince, and in these sediments, also, in Great Barrier Island, Bar- 

 trum has found granites, pegmatites, gamet-granulites, etc., in 



* Since this was writ-ten, Mr. Moir, a former student of tlie author, has observed 

 that the diorite in the Hollyford Valley invade; the (Triassic ?) annelid -bearing areywacke, 

 and Professor P.ark has confirmed this observation in many exposures in the Dairan 

 Mountains, further to the south. (Private communication.) 



t Private communication. 



