742 The American Naturalist. [September, 
posed to be of secondary origin. Bronzite and asbestus both occur in 
the rock. In the norite area of Arvien, Auvergne, the same author 
describes a variety of this rock which is characterized by the presence 
of secondary reaction, rims of anthophyllite and actinolite between its 
hypersthene and plagioclase, the former appearing next to the pyrox- 
ene. The plagioclase of the rock is often altered to actinolite, garnet 
and albite, while the hypersthene is changed to an aggregate of antho- 
phyllite. 
_The Granite of the Himalayas.—McMahon* describes the 
granite of the N, A. Himalayas. Although highly foliated in the bor- 
ders of its masses, the rock is shown to be eruptive. The author thinks 
the foliation is due to pressure upon the rock before it finally solidified. 
He attempted to show that this schistosity could not possibly have been 
produced after the rock cooled. The granite is coarsely porphyritic 
with large orthoclase crystals in a medium to fine grained groundmass 
composed of the usual constituents of granite. This is cut by tiny 
veins of quartz which are supposed to represent the micrystallized resi- 
due left after the first partial consolidation of the rock, or to be the 
result of a partial fusion of the quartz grains originally occurring in it. 
This quartz, though it presents the usual aspects of secondary quartz, 
is thought to have been injected into the vein spaces while it was in a 
molten condition. Sinuous areas and viens of microcrystalline mica 
are likewise observed in the granite, and these are thought to have been 
produced by the rapid crystallization of mica that had been melted, 
and not by the crushing and shearing of the original micas nor by sec- 
ondary processes of any other kind. The paper is well illustrated by 
photo-micrographs. 
California Rocks.—Fairbanks’ describes the rocks of Eastern Cal- 
ifornia between Mono Lake and the Mojave desert as comprising both 
sedimentary and igneous forms. Among the latter are both granitic 
and volcanic varieties. The granites form the eastern slope of the 
Sierra Nevadas. In the northern portion of the area it is a coarsely 
porphyritic biotite hornblende variety. In the southern portion it is 
replaced by a more basic phase containing less hornblende. The vol- 
canic rocks met with in the district are andesitic flows, dykes and tuffs, 
and basalt flows among the more recent rocks and liparites among the 
more ancient ones. The microscopical description of the type is 
deferred to a later paper. 
t Proc. Geologists Association, Vol. XIV, p. 287. 
5 Amer. Geologist, Vol XVII, p. 63. 
