34 Canadian Record of Science. 



The essential features of pegmatite formation seem to me 

 to be expressed in the above quotation with remarkable 

 clearness and distinctness. With this view of Charpentier's 

 most of the succeeding authorities seem to have come into 

 accord (such as De la Beche, Angelot, Bronn, G. Rose, 1 C. 

 F. Naumann, K.W. v. Giimbel, Th. Kjerulf, etc.) ; in France, 

 this view appears still to be very generally accepted. 2 



In opposition to this conception are the views with re- 

 gard to the genesis of pegmatite veins according to which 

 they were deposited from aqueous solution ; this theory 

 propounded by Saussure has since been modified in many 

 ways by different authorities. 



The hypothesis which at present is perhaps most gener- 

 ally accepted in Germany, explains the formation of the 

 pegmatite veins upon the so-called Lateral Secretion Theory; 

 this view has also been very generally adopted as an expla- 

 nation of the formation of veins of ore and of other similar 

 mineral veins. This principle laid down by Forchhammer 

 (hinted at also by older authorities), and advocated in re- 

 cent times chiefly by F. Sandberger and his followers, is, 

 however, even as regards the genesis of ore veins, by no 

 means proven, but on the other hand is most uncertain and, 

 according to my experience in the Norwegian ore deposits, 

 is quite improbable ; it has lately been strongly attacked by 

 A. W. Stelzner and others, and, as it appears to me, with 

 good reason. 3 



The very general adoption of this theory for the explana- 

 tion of the genesis of pegmatite veins was brought about 

 largely by S terry Hunt's work on Canadian pegmatite 

 veins, * and by a treatise, in many respects excellent, by H. 

 Credner, " Die granitischen Grange des sachsischen Granul- 



^ogg. Ann 1842,56. 



2 Cf. A. Lapparent's Geology ; also A. Michel-Le>y, " Structure et classifica- 

 tion des roches enlptives," Paris 1889, p. 15. 



3 " Die Lateralsecretions-Theorie," etc., Berg-u, Huttenm. Jahrb. etc, 

 1889, 37. 



4 " Geology of Canada." 1863 (p. 476 *nd 644); " Notes on granitic rocks," 

 "Amer. Journ. of Science," Ser. Ill, 1871 and 1872, " On Granites and Granitic 

 Veinstones" in Chem. and Geol. Essays, 1875, p. 187. 



