«4 ROYAL SOCIETY OF CANADA 



The rock has an allotnomorphic structure, approaching nearly in 

 character to the " mosaic " or " pavement " structure seen in meta- 

 morphic rocks. 



The reddish colour is apparently due to very minute reddish in- 

 clusions which occur in both feldspars indiscriminately, and whose pre- 

 sence in the 'other occurrences of the rock seems to be accompanied by 

 the alteration of any nepheline which may be present to a peculiar gie- 

 seckite-like aggregate. The reddish colour, in fact, seems to be due to an 

 incipient alteration of the rock, which is chiefly seen about the sides 

 of the mass. 



A chemical analysis of the rock by Professor Norton-Evans gave 

 the following results: — 



SiOg 65.89 



TiOg none 



AI2O3 19.73 



Fe.O, 2.03 



FeO .75 



MnO trace. 



CaO .46 



MgO .27 



K2O 3.95 



Na20 6.59 



P2O5 none 



S undet. 



CO2 .44 



CO2 44 



H2O .34 



100.45 

 The norm of the rock is as follows : — 



Orthoclase 23.35 per cent. 



Albite 55.54 



Anorthite 2.22 " 



Quartz 11.22 



Corundum 3.77 " 



Hypersthene .70 " 



Magnetite 2.32 " 



Pyrite .48 



99.60 

 Carbonic acid and water .78 



100.38 



