Bartrum. — The Distribution of Igneous Bocks in New Zealand. 419 



The norms and classifications 

 method are also appended. 



BiOg 

 AI2O3 



FeO 

 MgO 

 CaO 

 ■NaaO 

 K2O 

 H2O 

 TiOg 

 GO2 



P2O5 

 MnO 



99-93 



100-56 



99-5 



Norms and Classification. 



Quartz 



Orthoclase 



Albite .. 



Anorthite 



Diopside 



Hypersthene 



Magnetite 



Ilnienite 



Apatite 



(Water) 



99-96 



100-2 



99-3 



Classification .. II.5.3(4).4 'II.5.'4.'5 ir.5.4.'5 



(Andose.) 



A. Quartz-norite, Cleddau-HoUyford Saddle, New Zealand. (Dominion 



Analyst.) 



B. Quartz-gabbro, Carrok Fell, England. 



C. Gabbro, Druim an Eidhne, Isle of Skye. 



The norm agrees well with the observed mineral composition, although 

 it is difiicult to account for the apatite shown by the norm and indicated 

 by the chemical analysis : apatite appears to be practically absent from 

 the section examined. 



Another more typical coarse norite was amongst the material collected 

 by Mr. Holmes from the Cleddau-Hollyford Saddle. The plagioclase 

 (labradorite) and ferro-magnesian minerals are subequal ; of the ferro- 

 magnesians, hypersthene and augite are both plentiful, the former the more 

 so ; it is often finely lamellar ag in the quartz-norite, but the extinction 

 appears here to be straight. A brownish-green hornblende clouded by 

 dust-like iron-ore occurs in large crystals which poecilitically enclose the 

 pyroxenes and some feldspar. Some of the augite is intergrown with the 

 amphibole ; it is occasionally lamellar, passing to diallage. The hypersthene 

 14* 



