Turner — Rocks and Minerals from California. 423 



the acid except the rutile and zircon-like grains. The rutile is 

 the most abundant of the accessory constituents of the rock. 

 The next heaviest material was of a dark green color and com- 

 posed chiefly of amphibole. This was removed from the 

 separator, washed and dried and then put into another sepa- 

 rator and further purified. An examination of the powder 

 under the microscope showed only an occasional grain of 

 foreign material, so that the chemical analysis of this amphi- 

 bole may be taken as being very near its actual composition. 



Analysis of peculiar quartz-amphibole-diorite. 



8HS. N. 817 S. N. 



Quartz diorite. amphibole. 



Si0 2 54-64 50-08 



Ti0 2 -61 -76 



A1 2 3 12-09 8-13 



Fe 2 3 . 1-81 2-69 



FeO __ _.. 5-03 6-Yl 



MnO__ 0-13 0-49 



NiO 0-05 



CaO 7-74 11-21 



SrO trace none 



BaO 0-05 



MgO 11-86 16-31 



K 2 _ 1-01 0-46 



Na 2 2-35 1'22 



Li 2 trace 



H 2 below 110° C 0*12 none 



H 2 above 110° C 2*44 1-40 



P 2 0. _ trace 



C0 2 none 



F undet. undet. 



Total 100-01 99-46 



Analyst Hillebrand. Valentine. 



2. A New Amphibole-pyroxene Rock from Mariposa County, 



California. 



The amphibole-pyroxene rock to be described occurs in 

 small masses, pretty certainly intrusions, in the slates of the 

 Calaveras formation in the Sonora quadrangle, California. 

 The rocks were first collected by the writer about 1887, but 

 they were not investigated till 1895. The first published 

 notice of this rock may be found in the 17th Annual Report, 

 U. S. G. S., Part I, p. 670. This consists of a note by Dr. F. 

 L. Ransome stating the general character of the rock. 



The rock consists of original augite and original amphibole 

 in grains of nearly equal size, with a little quartz and some 

 pyrrhotite. Scattered abundantly through the rock are large 

 phenocrysts of brown amphibole which contain in a poikilitic 



