GEOLOGY OF CENTRAL SHEN-SI. 22%) 
This sequence of maroon conglomerate, mica-schist and graywacke, 
white quartzite, and gray limestone more nearly resembles the Sinian 
(Cambro-Ordovician) than any other Paleozoic terrane. The quartzite is 
not known elsewhere in that system, but may be regarded as a local 
replacement of a sandy limestone. The other members of the Hei-shui 
system in this northern section are such as might be derived by meta- 
morphism from the red Man-t’o shale and Ki-chédu limestone, which 
constitute the Sinian of Shan-si. We have shown reason to think that 
the strata of the southern section of the Hei-shui system represent the 
Middle Paleozoic and Carboniferous; and thus the entire series is pre- 
sumably equivalent to the Paleozoic. 
Liu-ytté-ho to Hei-shui-ho.—North of Liu-yiié-ho is a belt of strata, 
which underlie those of the Hei-shui system, are apparently separated 
from them by an unconformity, and are more strongly metamorphosed. 
We therefore regard them as Pre-Cambrian, and to distinguish them 
from other terranes of that era designate them the Kan-yti-wan schists. 
The Kan-yti-wan schists include mica-gneiss and schist, chlorite-schist, 
conglomerate-schist, limestone, and massive argillite. Into these have 
been intruded granites and other igneous rocks. The entire mass is folded, 
and both folds and contacts are now more or less obscured by the develop- 
ment of schistosity, which is nearly uniform at high angles regardless of 
the original rock structures. Although the sedimentary rocks are thus 
altered, the igneous intrusions, with a few exceptions, appear to be essen- 
tially unchanged. 
South of Chéu-chi-hién, along the northern slope of the Ts’in-ling 
mountains, the Kan-yti-wan schists are exposed in a belt 4 miles broad. 
The northern limit* is a fault-scarp, with alluvium covering the down- 
thrown side; the southern edge of the exposure is believed to be situated 
near Liu-yiié-ho. The following is the observed section: 
In the front of the mountains at Hei-shui-k’6u the rocks are gray 
schists, mostly silky sericite types such as commonly develop from the 
severe metamorphism of pure clay-rocks. Near the town these contain 
a member of pale-gray siliceous limestone, about 100 feet, 30 meters, 
thick. The schists and limestones are cut by quartz veins, several dikes 
of greenstone schist, and one of gray aplite (?). No other igneous rocks, 
except the large granitic intrusions, were found at any other locality in 
the Ts’in-ling-shan. 
Farther up stream the sericitic schists become greenish on account 
of an increase in the content of chlorite, and in places they develop into 
true chlorite-phyllites. From 1.5 to 4 miles, 2 to 6 kilometers, above 
* The basal gneiss observed by von Richthofen (China, vol. 1, p. 581) does not appear in this locality. 
