OF CENTRAL CANADA PART II. 



121 



one of which presents a sub-fibrous silky aspect, in chloritic slate. 

 Analysis of these varieties by Dr. Steriy Hnnt, will be found in the 

 elaborate Report of the Geological Survey for 1863. 



Olauconite (Green Sand) : This substance occurs only in the form of small 

 grains and specks of a green colour, distributed through sandstone and other 

 rocks. These grains appear to consist essentially of a hydrated silicate of 

 alumina, potash, and iron oxide. They occur in a sandstone of the Quebec 

 group near Point Levis, and on the Island of Orleans. Certain bright-green 

 markings in the siliceous Black River limestones of Lake St. John, in Rama, 

 have also been referred to Glauconite. 



(12) GROUP OF COPPER AND NICKEL SILICATES. 



[The minerals of this group, as regards Canadian examples, are com- 

 paratively unimportant. They are essentially hydrated silicates of an 

 amorphous or earthy structure : products of decomposition of copper 

 and nickel ores.] 



86. Chrysocolla : Green, greenish-blue, occasionally passing into 

 brown and black. In amorphous masses, and in earthy crusts on copper 

 ores, frequently mixed with malachite. H = 1.5 4.0 ; sp, gr. 2.1 



- 2.3. BB, blackens, and imparts a green colour to the flame-border, 

 but does not fuse. In the bulb-tube yields a large amount of water.. 

 Attacked and decomposed by heated acids. Average composition : 

 silica 34, oxide of copper 45, water 2 1 . The brown and black varie- 

 ties are intermixed with iron and manganese oxides, or with black 

 oxide of copper. In Canada, found sparingly amongst some of the 

 copper ores of Lake Superior. 



87. Genthite (Nickel-Gymnite) : Pale-green, greenish -yellow. Oc- 

 curs in earthy crusts, and in amorphous masses sometimes with botry- 

 oidal surface. H = 1.5 4.0; sp. gr. 2.22.5. BB. blackens, 

 but remains infusible, In the bulb-tube gives off a large amount of 

 water. A sofc earthy variety from Michipicoten yielded Dr. Sterry 

 Hunt: silica 35.80, oxide of nickel 32.40, water 12.20; but in an- 

 other specimen (less thoroughly dried before analysis) the amount of 

 water was found equal to 17.10 per cent. Hitherto only recognized 

 in Canada in a vein on the Island of Michipicoten, Lake Superior. 

 The vein traverses amygdaloidal trap, and carries small grains and 

 rounded masses of native copper and native silver. 



I. CARBONATES. 



[This subdivision comprises the natural compounds of Carbonic 

 Acid (now commonly called carbon dioxide) with various bases, such 



