no 



MINERALS AND GEOLOGY 



greyish-red cleavable masses, from the vicinity of Perth, in Lanarl 

 County, has been described under the name of Wilsonite. 



64. Wollastonite : White, pale-greenish, brown, grey, &c. Clino- 

 rhcmbic in crystallization, and of the pyroxene type, but occurring 

 sp. gr. 2.7 2.9. BB, more or less readily fusible. Decomposed, 

 commonly in thin tabular masses of fibrous structure. H = 4.5 

 5.0 ; with separation of gelatinous silica, by hydrochloric acid. 

 Essential composition : silica 51,7, line 48.3. In Canada, fibrous 

 Wollastonite occurs in many of the crystalline limestones of the 

 Laurentian series, mixed more or less intimately with pyroxene, 

 mica, quartz, and other minerals. Grenville Township in Argen- 

 teuil County, St. Jerome and Morin in Terrebonne, North Burgess 

 in Lanark, and Bastard in Leeds County, are the best known 

 localities. 



(7) GROUP OF NEPHELETIC SILICATES. 



[This group includes a small number of essentially anhydrous sili- 

 cates of alumina and soda, in some of which chloride of sodium is 

 also present, whilst others contain traces of chlorine or sulphuric 

 acid. They fuse more or less readily, and gelatinize in acids. 

 Canadian examples are .comparatively unimportant.] 



65. Nepheline, including Elceolite : White, brownish, greenish, 

 blueish-grey, yellowish, dull-red. Hexagonal in crystallization, but 

 occurring commonly in cleavable masses of a more or less greasy or 

 vitreo-resinous lustre, forming the variety known as Elseolite. H = 

 5.5 6.0 ; sp. gr. 2.5 2.65. BB, easily fusible. Decomposed 

 readily by acids, with separation of gelatinous or slimy silica. 

 Average composition: silica 44, alumina 44, soda 17, potash 5. 

 This species is said to occur in small orange-red granular masses in 

 boulders with orthoclase and black ainphibole, on Pie Island, Lake 

 Superior. Also, it is stated by Dr. Sterry Hunt, in white crystals 

 in the granitic trachyte of Brome. (Jancrinite, a closely allied 

 silicate, occurs, according to Dr. B. J. Harrington, in the nepheline- 

 syenites of Beloeil and Montreal. 



66. Sodalite: Blue, greyish, colourless, <fec. Regular in crys- 

 tallization, but occurring mostly in small granular masses. H = 5.5 

 6.0 ; sp. gr. 215 2.35. BB, melts with bubbling. Gelatinizes 

 in acids. Recognized in the form of small grains of a fine blue 

 colour, by Dr. Sterry Hunt, in the granitic trachyte of Brome. In 



