OF CENTRAL CANADA PART II. 139 



three inches in diameter, which rest on equally large pyramids of 

 amethyst-quartz, and are coated with iron pyrites in minute cubes> 

 the whole being surmounted, here and there, by scalenohedrons of 

 calcite. The fluor spar is partly of a pale greenish tint, but mostly 

 of a violet or amethystine colour. Pale green and purple cubes 

 occur also in most of the metalliferous veins of Thunder Bay and the 

 surrounding region, mostly with quartz, calcite, blende, galena, and 

 copper and iron pyrites, as at Prince's Mine, the Shuniah Mine, in 

 several veins in the township of Neebing, and in others near Black 

 Bay and Terrace Bay, on Fluor Island in Neepigon Bay, and else- 

 where. Also in amygdaloidal greenstone, near Cape Gargantua. 

 Fiuoi- spar occurs likewise, according to Mr. Murray, in association 

 with specular iron ore, in crystalline limestone on Lake Nipissing. 

 It occurs also, with apatite, in crystalline limestone in the township 

 of Ross, in Renfrew county on the Qttawa, and also, with heavy 

 spar, in Hull, and elsewhere in that district. Also in veins, with 

 galena and calcite, in Trenton limestone in contact with gneiss at 

 Baie St. Paul ; and in narrow veins In the Trenton limestone of the 

 vicinity of Montreal, and the Utica slates of Quebec. Small crystals 

 have likewise been obtained, from fissures and cavities of the Niagara 

 strata, in the neighbourhood of the Falls, and on the escarpment at 

 Hamilton. 



B. CHLORIDES. 



[This group is represented in Canada by a single type, the highly 

 important Chloride of Sodium, or Rock Salt. The presence of chlo- 

 rine in mineral bodies is easily ascertained by the blowpipe. Some 

 phosphor-salt, with a few particles of black oxide of copper, is fused 

 in a loop of platinum wire, so as to produce a deeply-coloured glass. 

 To this, a small portion of the test-substance, in powder, is added, 

 and the glass during fusion is held just within the point or edge of 

 the flame. The latter, if chlorine be present, will assume a rich 

 azure-blue colour from the volatilization r-f chloride of copper. Many 

 chlorides are soluble in water. None possess a metallic lustre, nor 

 is the degree of hardness in any species sufficient to scratch ordinary 

 glass.] 



108. Rock Satt : Colourless, and also variously coloured by acci- 

 dental impurities, as sesquioxide of iron, organic matters, &c., the 



