454 RESEARCH IN CHINA. 
tion to chlorite, magnetite, etc., is observable. As in No. 118, we find in 
this slide a few irregular garnets, which in the hand-specimen have a pale 
reddish color. 
CARBONATE ROCKS. 
Distorted black limestone, No. 121.—A typical specimen of the par- 
tially schistose coal-bearing limestone exposed in the canyon of the Han 
river, above Shi-ts’iian-hién. Specimen obtained 5 miles, 8 kilometers, 
above the city. 
This is a dense black rock having slaty structure and conchoidal habit 
of fracture. ‘The color is varied by indistinct bands and blotches of a lighter 
gray. 
The rock is composed of minute yet visible granules of calcite. The 
dark color is due to the presence of a large amount of graphite, occurring 
in the form of black specks or of wavy streaks. Here and there one sees 
calcite crystals of much larger size, and usually of a lenticular shape, lying 
with their longer axes parallel to the indistinct banding of the rock. The 
streaks of graphite are also much contorted. Subsequent in age to all 
these features, there are numerous veins of calcite which cross the rock in 
various directions. 
This limestone has been notably, although not severely, metamor- 
phosed. The contorted bands of graphite and the lenticular calcite bodies, 
embedded in a matrix which possesses a slightly schistose structure, indi- 
cate that the mass has been considerably deformed. Very little progress 
has been made, however, in the crystallization of the rock, and some of the 
larger bits of calcite resemble pieces of distorted fossil shells. 
Buff siliceous dolomite, No. 135.—The buff dolomite is associated with 
black slates (No. 133) and gray limestones in the valley of the Nan-kiang, 
about 1.5 miles, 3.5 kilometers, north of Pai-kiu-hia. In color, although 
not in composition, it resembles the buff marble near Liang-ho, and also 
certain limestones of the central part of the Ts’in-ling range. 
This is a dense aphanitic rock of light-buff color, traversed by veins 
and irregular masses of white quartz. 
The buff-colored portion is composed of minutely crystalline dolomite 
among which rhombic forms are frequently visible. The white patches 
consist of vein quartz which, if we may judge from its undulatory extinc- 
tion, has been subjected to intense strain. The greater part of this quartz 
has been sliced and granulated and the resultant debris has been arranged 
in parallel streaks of elongate ragged crystals. Dolomite is scattered 
through this mass in the form of irregular bodies, rhombic crystals, or more 
frequently as skeleton crystals which are intergrown with the quartz. 
