34 ROYAL SOCIETY OF CANADA 



The norm of the rock is as follows: — 



Orthocla&e 35.02 per cent. 



Albite 34.84 



Anorthite 6.67 " 



Nepheline 15.50 



Diopside .90 " 



Olivine 5-05 " 



Ilmenite .73 



Magnetite ' 6.15 " 



Apatite .34 



Calcite 3.45 



98.65 

 Water 1.03 



99.67 



The rock has thus the following position in the Quantitative Clas- 

 sification : — 



Class II Dosalane. 



Order 6 Norgare. 



Rang 2 Essexase. 



Sub-rang 4 Essexose. 



If the calcite be regarded as representing inclusions (and reasons 

 will be given for thus considering it later on), the rock will lie Just on 

 the line between Essexose and Laurdaiose. 



The calculation of the mode of the rock, that is to say the percen- 

 tage proportion of the minerals actually present in it, cannot be made 

 with absolute accuracy, since the precise composition of both micas pre- 

 sent is not known. If, however, the micas be taken to have the same 

 average composition as the lepidomelane from the nepheline syenite of 

 Litchfield, Me., (see Bull. 168, U.S. Geol. Survey, p. 21), except that 

 one per cent of alumina replaces an equivalent amount of ferric oxide, 

 as is frequently the case in these minerals, the mode will be as follows : — 



Orthoclase 4.45 per cent. 



Albite 50.83 \ r^ no 



Anorthite 1.24/ " 



Nepheline 8.05 " 



Biotite 29.61 



Iron Ore 73 



Apatite • 34 



Calcite 3.45 " 



Water 1.02 " 



99.73 



