88 T. S, Hunt an Oranitic Bocks. 



In 1863 I described certain veins in tlie crystalline schists of the 

 Appalachian region of Canada, " where flesh-red orthoclase occuis 

 so intermingled with (jhlorite and white quartz as to show the 

 contemporaneous formation of the three . • — ■ 



clase generally predominates, often reposing upon or surrounded 

 by chlorite ; at other times it is imbedded in quartz, whici 

 covers the latter. Drusy cavities are also lined with small crys- 

 tals of the feldspar, and have been subsequently 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 " • ^ ^ ^ 



ually predo 



clase and quartz, sometimes including mica, and having t 

 characters of a coarse granite ; the occasional presence of s 

 phurets of copper and specular iron characterizing all of thj 

 alike. It is probable that these, and indeed a great proporti 

 of quartzo-feldspathic veins are of aqueous origin, and h 

 been deposited from solutions in fissures of the strata, precisf 



elements. Among these are boron, phosphorus, fluorine, lithium, 

 rubidium, glucinum, zirconium, caesium, tin and columbium, 

 which characterize the mineral species apatite, tourmalin^ 

 lepidolite, spodumene, beryl, zircon, allanite, cassiterite, colum- 

 bite, and many others."— ( Geology of Canada, p. 476, also p. 644) 



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^ 

 J. D. Whitney, (this Journal, II, xxviii, 16). The association& 

 according to him, show the contemporaneous crystalhzation oj 

 the copper, natrolite, calcite and feldspar, which last was foun'i 

 by analysis to be a pure potash -orthoclase. 



§ 14. In 1864, this view was still farther insisted upon w 

 this Journal, (II, xxxvii, 252), where, in speaking of mineral 

 vemstones " which doubtless have been deposited from aqueoo- , 

 solution," it is added, -"while their peculiar arrangement, ^^ 

 the predominance of quartz and non-silicated species generaU.^ 

 serves to distinguish the contents of these veins from tho?e^ 

 injected plutonic rocks, there are not wanting cases in ^ '" 

 the predominance of feldspar and mica gives rise to aggi' - 

 which have a certain resemblance to dykes of intrusive u' 

 From these, however, true veins are generally distingui*-'- 

 the presence of minerals containing boron, fluorine, phosp- ^ 

 caesium, rubidium, lithium, glucinum, zirconium, tin. com_ 

 bmm, etc. ; elements which are rare, or found only in min^^ 

 quantities in the great mass of sediments, but are here accurn" 

 lated by deposition from waters, which have removed ^^ 



