380 



University of California Publications. 



[Geology 



From the chemical point of view we find karinthine (and par- 

 gasite) as a form intermediate between gastaldite on the one 

 hand, and common hornblende (edenite or soretite) on the other 

 hand. (Table III.) Karinthine and pargasite are more or less 

 similar in their metallic constituents, but pargasite contains an 

 appreciable quantity of fluorine, which replaces silica (in an 

 equal coefficient, =10). This chemical difference, together with 

 the positive optic character of the amphiboles of Pargas, justifies 

 us in distinguishing between pargasite and karinthine. Besides, 

 pargasite is quite different from karinthine both in its genesis 

 and in its occurrence, which is another argument for the identifi- 

 cation of the bluish amphibole from the glaucophane schists with 

 karinthine. On the Calif ornian karinthine (?) I have made the 

 following determinations: Pleochroism: C = greenish blue to 

 bluish green, b = olive green, a = pale yellow to greenish yel- 

 low. Absorption C^b>a. Angle of extinction variable. C-.c 

 = 17-22, in obtuse angle /?. The angle measured on cleavage 

 lamellae is hardly different from the maximum angle measured 

 in slides and on (010). The axial plane is parallel to (010). 2 E 

 very large, optic character negative, y — /? = ca. 0.022. Small 

 dispersion, p < v. 



In some schists from California (and also in some from the 

 Alps) I have found a dark green or black hornblende with: 



C = greenish blue to light ultramarine, 

 Pleochroism : fa = olive green to dirty green, 



a = honey-yellow to greenish yellow. 



Angle of extinction in general larger than in the former karin- 

 thine, C:C = 20°-28? Other properties almost the same. In 

 one section only (II, 6). I found also a positive hornblende as- 

 sociated with glaucophane: C = b = greenish, a = colorless, C:c 

 = -48°; 2 V very small, axial plane (010). Unfortunately we 

 possess no analysis of the Californian karinthine to see whether 

 the conclusions stated for glaucamphiboles hold in the karinthine 

 series. I may remark, however, that some Al (and Fe'") in the 

 existing analyses belongs to a syntagmatite formula (orthosili- 

 cate), as in the syntagmatite of Jan Mayen, philipstadite, sore- 

 tite, etc. Karinthine is almost Fe'" — free ; philipstadite, hud- 



