188 



SMITH— PARAGENESIS OF MINERALS. 



[October 5, 



if^i 



There can be no doubt that the blue aphibole that is so common 

 in the metamorphic rocks of the Coast^ Ranges, from Oregon to 

 San Diego, is mostly true glaucophane, for the writer has examined 

 at least 300 slides from all over this great region, and has found 

 the orientation to be that of the type from Syra, except in the cases 

 mentioned above. It is likely, however, that a chemical study of 

 this mineral from these different localities will disclose the presence 

 of many varieties, some of which may eventually be designated by 

 special names. It is associated with epidote, garnet, and lawsonite, 

 and usually with mica, either muscovite, paragonite, biotite, or 

 margarite. The rocks in which it is found are metamorphosed di- 

 orites, greenstones, pseudodiorites and pseudodiabases, eclogites and 

 glaucophane schists. 



It is probable that the variety gastaldite is present among the 

 glaucophanes of California, for there are numerous occurrences of 



Table of Analyses of Glaucophanes. 



I. Analyst, W. C. Blasdale, Bull. Dept. Geol. Univ. Calif., Vol. II., 338. 



II. Analyst, W. C. Blasdale, Bull. Dcpt. Geol. Univ. Calif., Vol. II., 338. 



III. Analyst, O. Luedecke, Zcitschr. Dcittsch. Geol. Gescll, Vol. 28, p. 249. 



IV. Analyst, H. S. Washington, Amcr. Jour. Sci., 4th Ser., Vol. XL, p. 40. 



V. Analyst, W. S. T. Smith, in C. Palache, Bull. Dept. Geol. U. C, 

 p. 188. 



VI. Analyst, H. B. Foullon, Sitab. Akad. JViss. IVien, Vol. C, p. 174- 



VII. Analyst, Cossa, Accad. Line. Rom., 1875, Vol. II., p. 2>3- 



