Section C— GEOLOGY. 



1.— DISTEIBUTION OF THE IGNEOUS EOCKS OF 

 NEW ZEALAND. 



By P. MARSHALL, M.A., D.Sc. 



[With Map.] 



Although Captain Hutton published descriptions of many types of 

 igneous rocks of New Zealand, and stated the localities from which his 

 specimens were obtained, he made little or no attempt to define the 

 areas over which such rocks might be found. Other authors have 

 from time to time published descriptions of rocks of small areas, or have 

 given generalised accounts of the occurrence of certain kinds of rock. 



Of these authors, Hochstetter, in 1866, laid the foundations of our 

 knowledge of the distribution of igneous rocks of the Auckland and 

 Nelson provinces, and in his account Avere included detailed descriptions 

 of some of the Taupo rocks by Zirkel. 



Sir James Hector, in his " Handbook of New Zealand Geology," 

 distinguishes only between basic and acidic igneous rocks. 



In Otago, Hutton, in his " Geology of Otago and Southland," 

 gives a general idea of the distribution of the rocks that he had found 

 within the limits of those provinces. Haast, in his " Geology of 

 Canterbury and Westland," has done similar work for these more 

 northern provinces, while descriptions of many of the volcanic rocks of 

 Banks' Peninsula are to be found in Filhol's " Voyage au Pol Sud." 



More recently Rutley has described some of the rocks of the Thames 

 area, and Sollas has added greatly to these in two volumes of rock 

 descriptions lately published by the New Zealand Government. 



The important alkaline area of the Otago Peninsula was first 

 recognised by Ulrich, for Hutton had previously described these phono- 

 lites as andesites and trachytes. This area has lately been more fully 

 described by the present author (Q.J.G.S., 1906). 



In addition to these larger memoirs, other descriptive papers are 

 to be found in some number in the volumes of the " Transactions of 

 the New Zealand Institute." The more important of these are : — 

 Hutton on the Andesites of Coromandel ; Cox on the Rhyolites of 

 Mount Somers ; Thomas — Rocks of Tongariro and Taupo ; Speight 

 — Rocks of Kermadecs and Banks' Peninsula ; Marshall — Peridolites 

 of Milford Sound ; Park — Andesites of Thames Goldfields ; Shrewsbury 

 — The Auckland Volcanoes. 



The titles of many others will be found in a list of papers on the 

 Geology of New Zealand that was compiled by Mr. A. Hamilton. 

 (T.N.Z.I., 1902.) 



