440 RESEARCH IN CHINA. 
GRANITES. 
The granites of the Ts’in-ling mountains were first noted and briefly 
described by von Richthofen.* Since then other descriptions, based upon 
microscopic study of the rocks, have been published.f All are brief and 
generalized, but they refer to localities both east and west of our route and 
hence give an idea as to the uniformity and distribution of the granites. 
Hornblende-biotite granite, No. 113.—This granite is characteristic of 
the main divide of the Ts’in-ling range. It has been intruded into meta- 
morphosed sedimentary rocks, which are almost certainly late Paleozoic 
in age. Specimen obtained near the contact between the granite and the 
older rocks on the north side of the Ts’in-ling divide, near W6n-kung-miau, 
Shen-si. 
By the influence of the granite intrusion the dark slates near the con- 
tact have been changed into medium-grained black mica schists. The 
junction is sharply marked by an irregular line across which occasional 
small dikes of granite extend into the country rock. A specimen (No. 112) 
collected at the very contact shows interesting variations in both granite 
and schist. 
Between the spotted granite and the contact there is a layer, a little 
more than a centimeter thick, which is nearly white and is evidently poor 
in ferro-magnesian minerals. The microscope reveals quartz and ortho- 
clase in about equal proportions, with a little biotite. 
This passes abruptly into a rock of finer grain composed of quartz with 
feldspar and abundant shreds and short bits of red-brown biotite. Although 
the micas have a rude parallel arrangement the rock is not banded. Here 
and there much larger crystals of orthoclase and microcline are embedded 
in the schist. They are always filled with inclusions of biotite. At other 
points in the schist, muscovite becomes as abundant as biotite; or still else- 
where we may have an abundance of small black particles of magnetite. 
The Ts’in-ling granite is a speckled black-and-white rock of medium 
grain. It is composed largely of white and glassy feldspars, clear quartz, 
and blackish hornblende and mica. A few of the feldspars are much larger 
than any of the others, and yet the rock has not the appearance of a por- 
phyry, because the phenocrysts contain abundant inclusions of smaller 
crystals which interrupt the cleavage faces and make them much less 
conspicuous. 

* Von Richthofen: China, vol. 11, p. 570. 
Steuer: Mittheilungen iiber Gesteine aus dem Chinesischen Provinzen Kansu, Schensi, Hupe, und 
Honan, (Neues Jahrbuch fiir Min., Geol., und Pal., x, pp. 477-494.) 
Koch: Report on Rocks collected by Iécezy in Asia (Wissenschaftliche Ergebnisse der Reise des 
Grafen Béla Széchenyi in Ost-Asien, 111). 
