OP ARTS AND SCIENCES. 303 



Ferrous oxide 2.45. 



Manganous oxide 48. 



Lime 17.45. 



Magnesia 2.14. 



Soda 19. 



Water 1.13. 



Titanic acid 1.72. 



99.91. 

 Free quartz, 10.86 per cent. Sp. gr. 3.45. 



Metallic copper, 3.43 per cent. Sp. gr., calculated after deducting for quartz 

 and copper, 3.32. 



(I.) 1. Plagioclase. 2. Ptkoxenb. 



(n.) 



Characteristic 

 paeudomorphs. 



(III.) "Wliolly clianged to 



PKEHNITE. 



(IV.)? Calcite? 



(V.) E PI DOTE. 



(VI.) Quartz after (Calcite after)? prehnite. 



Forming 80 %^ot the rocli. 



The rest of the specimen is a very irregular mixture of the purple 

 quartz matrix (with its quartz amygdules), and light-green epidote 

 impregnated with rough threads of copper. 



In thin sections it is found to consist of epidote, with more or less 

 distinct crystal outlines, a soft, yellowish-green substance, and quartz 

 which encloses the two other constituents, and permeates the mass in 

 such a manner as to make it evident that it has replaced some pre- 

 existing substance — calcite? — in which the epidote and green sub- 

 stance lay. 



That the quartz is younger than the epidote is shown by the fact 

 that crystals of this are included in integral quartz grains. 



Paragenesis : — 



Epidote 2. Quartz. 



1. Soft, yellowish-green substauce. 



