394 THE CANADIAN NATURALIST. [DeC. 



jet of pasty matter derived from a consolidating granitic mass. 

 Daubrde and Scheerer, in describing the granitic veins of Scandina- 

 via, conceive the material filling them to have been derived from 

 the enclosing crystalline strata instead of an unstratified granitic 

 nucleus, but do not, so far as I am aware, compare their formation 

 to that of concretionary veins. Their publications on this subject, 

 it should be said, are both anterior to the essay of de Beaumont. 



§ 12. The notion that all granitic veins are the result of some 

 process of injection, and not to be confounded with concretionary 

 veins, seems indeed to have been general up to the present time. 

 Even von Cotta, while strongly maintaining the aqueous and 

 concretionary origin of metalliferous veins in general, when 

 describing those consisting of quartz, mica, feldspar, tourmaline, 

 garnet, and apatite, with cassiterite, wolfram, etc., which occur at 

 Zinnwald and at Johaun georgenstadt, is at a loss whether to regard 

 these veins, from their granitic character, as igneous-fluid 

 injections or as concretionary lodes. In support of the latter view 

 he refers to their more or less regular and symmetrically banded 

 structure, and while recalling the fact that mica and feldspar may 

 both be formed in the humid way, considers the nature of these 

 veins to be very problematical, and the question of their origin a 

 diflacult one. — {Ore Deposits., Prime's translation, 1870, pages 

 110—12-1). 



§ 13. I have for several years taught that granitic veins of the 

 kind just referred to are concretionary and of aqueous 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 subsequently filled with cleavable 

 bitter-spar, sometimes associated with specular iron, rutile and 

 sulphuretted copper ores." A study of these veins shows a tran- 

 sition from those " containing quartz and bitter-spar with a little 

 chlorite or talc, through others in which feldspar gradually pre- 

 dominates, until we arrive at veins made up of orthoclase and 

 quartz, sometimes including 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 



