XL] GRANITES AND GRANITIC VEIN-STONES. 193 



of mineral vein-stones " which doubtless have been deposited 

 from aqueous solution," it is added, " while their peculiar ar- 

 rangement, with the predominance of quartz and non-silicated 

 species, generally serves to distinguish the contents of these 

 veins from those of injected plutonic rocks, there are not 

 wanting cases in which the predominance of feldspar and mica 

 gives rise to aggregates which have a certain resemblance to 

 dikes of intrusive granite. From these, however, true veins 

 are generally distinguished by the presence of minerals contain- 

 ing boron, fluorine, phosphorus, caesium, rubidium, lithium, 

 glucinum, zirconium, tin, columbium, etc. ; elements which are 

 rare, or found only in minute quantities in the great mass of 

 sediments, but are here accumulated by deposition from waters 

 which have removed these elements from the sedimentary rocks 

 and deposited them subsequently in fissures." 



In the Report of the Geological Survey of Canada for 1866 

 (p. 192), I have, in describing the veins of the Laurentian 

 rocks, insisted still further on the distinction just drawn be- 

 tween granitic dikes and granitic vein-stones, which latter I 

 have proposed to call endogenous rocks, to indicate the mode 

 of their formation, and to distinguish them from intrusive or 

 exotic rocks, and sedimentary or indigenous rocks. 



15. The peculiar banded arrangement, which is so charac- 

 teristic in concretionary veins not granitic in composition, is 

 probably not less marked in granitic vein-stones, and often ap- 

 pears in these in a remarkable manner, showing that they have 

 been formed by successive depositions of mineral matter, and 

 generally in open fissures. This structure, and various pecul- 

 iarities to be observed in granitic vein-stones, will be best illus- 

 trated by descriptions of various localities, most of which I 

 have personally examined. It is proposed to notice, first, the 

 veins of the gneiss and mica-schist series of New England ; 

 and, secondly, those of the Laurentian rocks of New York and 

 Canada. In the latter class will be noticed the more or less 

 calcareous vein-stones into which the Laurentian granitic veins 

 are found to graduate. 



16. It is in the series of micaceous schists with interstrati- 

 9 M 



