386 



University of California Publications. 



[Geology 



enr in the group of common hornblende, and are very probably 

 Fe'" — amphiboles corresponding to the karinthine, barkevikite, 

 or soretite formula. Until more detailed knowledge about this 

 kind of amphibole is published, I propose to retain for such the 

 name laneite, in honor of Dr. A. C. Lane, who has introduced 

 new ideas and made new observations in this group of minerals. 



Actinolite and an Actinolite with Transverse Axial Plane. — 

 As a type of the actinolite from the rocks with glaucophane, 

 we may take the actinolite of North Berkeley and San Pablo 

 studied and analyzed by Blasdale (loc. cit.). It is very similar 

 in its physical properties to the actinolite described by C. Pa- 

 lache as occurring in crossite schists, etc. Color, bluish green ; 

 pleoehroism: C = bluish green, 6 = yellowish green, a = yel- 

 lowish to colorless; absorption faint, C >f) > a. Angle of ex- 

 tinction C:c = 15°; birefringence as usual; 2 E very large; the 

 section (100) shows a negative bisectrix and one axis. 



In one glaucophane schist (VIII 10) I found an interesting 

 mineral which seems to be an actinolite with transverse axial 

 plane. The relief is like zoisite. Pleoehroism, C = colorless, b 

 — green, more or less dark, a == yellowish to colorless; angle of 

 extinction, 6:C = -7° (measured on hemitropic lamellae which 

 extinguish symmetrically). In the sections with parallel extinc- 

 tion the axial plane is transverse, with 2 E small around a posi- 

 tive bisectrix. Some lamellae show patches of glaucophane. 



From the occurrence and optical properties of this mineral, 

 it can be no other than an amphibole, viz., an actinolite. I have 

 met with it only in one rock (3 slides), and in so small a quan- 

 tity that it was not possible to isolate it for further investigation. 



I may here again remark that the position of the axial plane 

 is near to the vertical, as in crocidolite and osannite, and not near 

 to the horizontal, as in crossite and laneite. 



