OF CENTRAL CANADA PART II. 113 



lime, in some of the amygdaloidal traps of Lake Superior. Also in 

 trap rocks around Montreal. 



75. Analcime : White, greyish, pale-red, &c. Regular in 

 crystallization : the crystals mostly trapezohedrons. Occurring 

 also in small granular masses. H = 5.0 5.5 ; sp. gr. 2.2 2.3. 

 BB, imparts a yellow tinge to the flame, and melts without bubbling 

 or intumescence into a more or less clear glass. In the bulb-tube, 

 gives off water in considerable quantity. Gelatinizes in acids. 

 Average composition: silica 54, alumina 23, soda 14, water 9. 

 Occurs in the amygdaloidal traps of Lake Superior, and more es- 

 pecially, with native copper, on the Island of Michipicoben. It is 

 said also to be present, here and there, in the trap rocks of the 

 district around Montreal. 



76. Apophyllite: "White, pale-red, &c. Tetragonal in crystalliza- 

 tion, but occurring commonly in lamellar masses of a somewhat 

 pearly aspect. (The crystals exhibit a pearly opalescence on the 

 basal plane, and a vitreous lustre on the other faces.)* H = 4.5 ; 

 sp. gr. 2.3 2.4. BB, easily fusible, and yielding a large amount 

 of water in the bulb-tube. Decomposed, with separation of floccnlent 

 silica, by hydrochloric acid. Apophyllite differs from other zeolitic 

 minerals in being non-aluminous. Average composition : silica 52, 

 lime 25, water 16, potassium fluoride 6J- Occurs in pale reddish 

 and colourless foliated masses, mixed with calcspar, in the silver- 

 bearing vein of Prince's Location, on Spar Island, Lake Superior. 



(9) GROUP OF MICACEOUS AND CHLORITIC SILICATES. 



[The silicates of this group possess an eminently fissile or foliaceous 

 structure, in consequence of which they admit of separation into plates 

 or scales of extreme tenuity. Although differing more or less in 

 composition, they form a connected series, commencing with species 

 which consist essentially of silicates of alumina and potash, anhydrous 

 or nearly so, and terminating in hydrated silicates of alumina and 

 magnesia, but with intermediate species in which both potash and 

 magnesia are present, and in which the amount of water gradually 

 increases. Many of these intermediate links, however, have not been 

 met with, as yet, in Canada. Through the hydrated magnesian 

 species, there is a transition into the talcose minerals of the next 

 group.] 



* See Types of Crystallization, in the author's Mineral Tables, page 276. 

 9 



