ROCKS FROM NORTHERN AND CENTRAL CHINA. 359 
Hornblende occurs only rarely in the Khin-gan granite. It is olive- 
green, with the pleochroism ranging from pale yellowish-green to dark 
olive. Most of the crystals have been altered in the upper zone, the process 
resulting in the formation of chlorite and epidote. 
Biotite is the only abundant ferro-magnesian mineral present. It 
occurs in irregular olive-brown plates, which are partially altered to chlorite, 
epidote, and magnetite. The chlorite develops along the edges of the 
flakes and grows inward in streaks along the cleavage, until, in some cases, 
it has formed pseudomorphs after the biotite. 
Of the less common constituents, titanite appears in the familiar 
wedge-shaped crystals and irregular grains, usually in association with 
biotite. Magnetite, as a primary constituent, forms angular grains, sparsely 
distributed, and together with ferric oxides is a secondary product of the 
alteration of the ferro-magnesian minerals. Small prisms of apatite, 
zircon, and a few of tourmaline, are scattered through the rock; as usual, 
they were among the first minerals to crystallize. 
Evidences of deformation are not prominent in this granite. The 
effect of permanent strain is seen in the undulatory extinction of the 
quartzes. The parallel streaks of inclusions, which traverse many of the 
crystals of both quartz and feldspar irrespective of crystal boundaries, 
may also be due to dynamic metamorphism.* 
LIAU-TUNG DISTRICT. 
This district includes the peninsula of Liau-tung in southern Man- 
churia. Geologic studies by the writer were limited to the western 
border of this mountainous region. The rocks observed belong to several 
distinct systems: (a) the T’ai-shan gneissic complex (Archean), (6) the 
Ta-ku-shan system of schists, quartzite and marble (Algonkian), (c) the 
Sinian system (Cambro-Ordovician), and igneous dikes. 
TA-KU-SHAN SYSTEM. 
Rocks OF SEDIMENTARY ORIGIN. 
Crumpled sideritic slate, No. 61.—This slate is a phase of the dark-red, 
gray, and black slates which lie beneath marble and quartzite at Ta-shi- 
kiau station on the railroad to Port Arthur. The strata are only moder- 
ately metamorphosed. The most conspicuous features of the rock are the 
red-brown rhombs of iron ore which are abundantly interspersed through 
the gray silky slate. The cleavage planes are crumpled and ribbed in 
parallel lines. On closer examination the mass is seen to consist of 
finely divided quartz, kaolin, sericite, etc.—a typical clay slate. 
* Streaks of similar inclusionsjingquartz-schist from the Black Hills are regarded by Van Hise as 
metamorphic developments. (G.§. A. Bull. 1, p. 217.) 
