The Rev. S. Haughton's Notes on Mineralogy. 



221 



No. XIV. Analysis of Green Orthoclase from Greenland. 



4 

 1 





Per cent. 



Atomic constitution. 



Silica . . . 



, 64-40 



1-431 



1-431 < 



Alumina . . 



18-96 



0-364 1 



> 0-377 



Peroxide of iron 



. 1-04 



0-013J 



Lime » . . 



0-45 



0016 ] 





Magnesia . 



014 



0007 



> 0-377 



Soda . . . 



2-35 



0-076 



Potash „ . . 



1307 



0-278 J 





100-41 



This orthoclase was brought to Dublin from Greenland by Sir 

 Charles Giesecke, and is beautifully crystallized in flat tabular 

 masses. It gives the usual formula, 



RO, Si0 3 + Al 2 3 ,3Si0 3 . 



No. XV. Analyses of Volcanic Rocks from New Zealand. 



I am indebted to Dr. Lauder Lindsay for the -opportunity of 

 making the following analyses of volcanic rocks from Dunedin 

 in New Zealand. 



1. Basalt, with visible crystals of Augite and JChrysolith. 

 Dunedin, New Zealand. 



Per cent. 



Silica 46-60 



Alumina 16-80 



Peroxide of iron . . . 7*28 



.Protoxide of iron . . . 5 # 76 



Protoxide of manganese . 0*72 



Lime 9'65 



Magnesia 689 



Soda 6-78 



Potash 2-08 



Titanic acid trace 



10256 



2. Vesicular Augitic Lava, with cavities destitute of lining 

 'crystals. Mount Eden, Auckland, New Zealand. 



This lava is divisible into two portions, soluble and insoluble 

 in muriatic acid : — 



Soluble ...... 38-2 



Insoluble ... . . . 61*8 



100-0 



It contains only a small quantity of carbonates, and seems t to 

 have undergone but little metamorphic action. 



