PRESIDEKt'S address — SECTION c. 67 



gieal examination of McKay's collections. This work, so rapidly and 

 accurately accomplished, must remain one of the triumphs of those 

 pioneer geologists. It has since been somewhat modified by Park 

 (1886), and applied (1904) to the succession of Triassio beds at 

 Nugget Point in south-eastern Otago. Apart from these regions 

 where a long succession of fcssilifercus zones are present, McKay 

 has recognised portions of the sequence in many parts of the two 

 main islands. Trechmann's investigations in the field and his 

 palaeontological work confinn the succession of beds in these areas, 

 and serve to define their eixact age and fauna! relationships. The 

 various ages that have been assigned to them are shown sufficiently 

 in Table II. We must consider their character and geographic 

 distribution, and note first that from lowest fossiliferous horizon 

 (top O'f the Middle Triassic) to the close of the Rhaetic, the thick- 

 ness of the series of sediment is nearly 10,000 feet. In 

 Southern Otago, the more or less schistose rocks north of the 

 Clutha River, merge southwards into a mass of greywackes and 

 conglomerates over 6,000 feet thick, containing in its upper 

 portion a small fauna, the fossiliferous zone being traceable south- 

 eastward to Nugget Point. Similarly in Northern OtagO' beyond 

 th« intervening mica-schists the semi-metamorphic Maitai or 

 Aorangi rocks ("Kurow schists"), are followed by a fossiliferous 

 zone of argillites and conglomerate with an analogous fauna which 

 also is found in Mt. Potts in the heart of the ranges of West 

 C'ant(>rbury. and again in the Nelson district, where tht/r strati-' 

 graphical relationship to adjacent formations is obscured. These 

 occurrences belong to the Kaihiku series of the early geologists. 

 Trechmann (191 7a) shows that they, are characterised by Daonella 

 indica and Spiriferina frarfilis, with forms of Halorella, Mentze- 

 liopsis, Entrochiis, and Isocrinus, indicating a horizon equivalent 

 to the top of Alpine Middle Triassic formation, i.e., they are 

 Ladino-Carnic in age. 



These are followed by Carnic beds with a prolific fauna of over 

 fifty species, which may be grouped into several sub-zones. They 

 have been recognised along the south-western side of the Hokonui 

 Hills, and its continuation in the Moonlight Ranges, and probably 

 are indicated by the fossiliferous rocks which were noted by 

 Hector (1891, p. LXL), between the head of Lake Wakatipu and 

 the plutonic rocks of the Sounds region. These pass eastward into 

 Te Anau rocks, and thence into the metamorphic rocks of Queens- 

 town and Central Otago. The same fauna is found in various 

 localities along the western mountainous portions of the Canter- 

 bury province. Halohia and Mytilvs are abundant, with Adon- 

 tophoria and Mynplmria (formerly classed as Triqonia, and thought 

 to be a Jurassic forerunner), five species of Spiriferina, Retzia, and 

 S'lnriffera, together with a group of cephalopods, including Pro- 

 dvdonantihis and Discnphyilites. This was termed the Oreti 



