Orthoclase from the Nepheline Syenite of Ontario. 17 



Silica 43-51 



Alumina 33*78 



Ferric oxide . . . • 15 



Lime . . -16 



Magnesia tr. 



Potash.. 5-40 



Soda 16-94 



Loss on ignition -40 



100-34 



Hardness nearly 6. Specific gravity at 17° C. = 2-625 as 

 determined with the bottle and 2*618 as determined by sus- 

 pension with a hair. The specimen analyzed was white, sub- 

 vitreous or slightly oily in luster, translucent, and sub-con- 

 choidal to uneven in fracture. Before the blowpipe it fused 

 quietly at about 3*5 to a colorless, slightly vesicular glass. It 

 is described as nepheline rather than elseolite because of the 

 luster being only slightly oily. The two names also seem 

 unnecessary. 



At a number of points in the region in question Dr. Adams 

 found the mineral sodalite in the form of veins, streaks and 

 irregular masses in the nepheline syenite. The masses were of 

 various sizes, the largest observed being 10x10x4 inches ap- 

 proximately. Specimens from lot 25 range xivof Dungannon, 

 which he has given me for analysis are weathered rusty super- 

 ficially, but upon fresh fracture are of a fine smalt-blue color. 

 They are traversed by a few little veins of a white and reddish 

 mineral which proves to be orthoclase. The sodalite also con- 

 tains scales of a dark brown to black mica. Some of the 

 pieces were compact and microscopically showed no cleavage 

 but one which was selected for examination showed distinct 

 dodecahedral cleavage and vitreous luster. Its hardness was 

 about 5*5 and its specific gravity at 16'5° C. was 2 - 295. On 

 analysis the following results were obtained : 



Silica 36-58 



Alumina 3T05 



Ferrous oxide -20 



Socla 24-81 



Potash -79 



Chlorine.. 6-88 



Sulphuric anhydride -12 



Water -27 



Insoluble.. -80 



101-50 

 Deducting O = CI 1'55 



99-95 



A.\r. Jour. Sci.— Third Series, Vol. XLVIII, No. 283.— July, 18J)4. 

 2 



