192 GRANITES AND GRANITIC VEIN-STONES. [XI. 



origin. In 1863 I described certain veins in the crystalline 

 schists of the Appalachian region of Canada, " where flesh-red 

 orthoclase occurs so intermingled with chlorite and white 

 quartz as to show the contemporaneous formation of the three 

 species. The orthoclase generally predominates, often reposing 

 upon or surrounded by chlorite ; at other times it is imbedded 

 in quartz, which covers the latter. Drusy cavities are also 

 lined with small crystals of the feldspar, and have been subse- 

 quently filled with cleavable bitter-spar, sometimes associated 

 with specular iron, rutile, and sulphuretted copper ores." A 

 study of these veins shows a transition from those " containing 

 quartz and bitter-spar, with a little chlorite or talc, through 

 others in which feldspar gradually predominates, until we ar- 

 rive at veins made up of orthoclase and quartz, sometimes in- 

 cluding mica, and having the character of a coarse granite ; the 

 occasional presence of sulphurets of copper and specular iron 

 characterizing all of them alike. It is probable that these, and 

 indeed a great proportion of quartzo-feldspathic veins, are of 

 aqueous origin, and have been deposited from solutions in 

 fissures of the strata, precisely like metalliferous lodes. This 

 remark applies especially to those granitic veins which include 

 minerals containing the rarer elements. Among these are 

 boron, phosphorus, fluorine, lithium, caesium, rubidium, gluci- 

 num, zirconium, tin. and columbium ; which characterize the 

 mineral species apatite, tourmaline, lepidolite, spodumene, 

 beryl, zircon, allanite, cassiterite, columbite, and many others." 

 (Geology of Canada, pp. 476, 644 ; and ante, p. 33.) 



In this connection I referred to the occurrence of orthoclase 

 with quartz, calcite, zeolites, epidote, and native copper in cer- 

 tain mineral veins of Lake Superior, so well described by Pro- 

 fessor J. D. Whitney. (American Journal of Science (2), 

 XXVIII. 16.) The associations, according to him, show the 

 contemporaneous crystallization of the copper, natrolite, calcite, 

 and feldspar, which last was found by analysis to be a pure 

 potash-orthoclase. 



14. In 1864 this fiew was still further insisted upon in 

 the Journal just cited ((2), XXXVII. 252), where, in speaking 



