GEOLOGY OF CENTRAL SHEN-SI. 305 
Hing-an-fu to Sha-ts’uan-hién.—We ran the stretch of 105 miles, 169 
kilometers, from Shi-ts’tian-hién to Hing-an-fu in boats in 28 hours, not 
counting stops. The river flows in a canyon 1,000 to 4,000 feet, 300 to 
1,200 meters, deep, frequently between precipitous bluffs, which rise 100 
feet, 30 meters, or so above the water’s edge, and which are in general 
surmounted by long steep slopes. Throughout the entire distance there 
is a practically continuous section of the limestones, slates, and schists of 
the Han system, with occasional large dikes. 
For 8 to 10 miles, 13 to 16 kilometers, above Hing-an-fu the banks 
consist of the characteristic gray phyllites, which we consider to be the 
K’ui-chéu schists. Near Siau-tau-ho coal is mined in black siliceous slate, 
which we assign to the Wu-shan formation. The contact between the 
K’ui-chéu schists and this belt of the Wu-shan probably crosses the river 
in a west by north direction, between Lan-ho-k’ou and Liu-shui-tién 
(atlas sheet 6 4). Extended southeasterly, it passes south of Nu-wang- 
miau, where we have already noted it. 
The coal a mile below Siau-tau-ho is a bony anthracite with much 
pyrite. It is mined at intervals from the river to the summit of the ridges, 
the dip being nearly vertical, though contorted. A score of openings may 
be seen, and in the half dozen visited the bunches of coal vary from 1 to 
12 feet, .3 to 3.5 meters, in width, up to 30 feet, 10 meters, in height, and 
from 1 to several hundred meters in length. The lenses represent formerly 
continuous but now badly squeezed beds, which may have been 4 or 5 
feet thick. They are repeated on an anticline, which is well-exposed in 
some of the upper workings. Although the coal is very inferior, it is quite 
extensively mined and shipped down the river. The price at the river 
bank is 75 cash a picul, about 70 cents a ton. 
Just at Siau-tau-ho there are other mines in which the dip is 15° to 
40° northeast. We regard this occurrence as the southwestern side of a 
local syncline and the vertical dips a mile down the river as the adjacent 
anticline, northeast of which the beds dip under the succeeding K’ui-chéu 
schist. 
Between Ta-tau-ho and a sharp bend a mile south by west from 
Han-wang-chéng we observed chiefly soft olive and gray phyllites, locally 
dotted with small octahedra of magnetite and of the general character 
of the K’ui-chéu schists; but the very sharp bend that the Tung-ho enters 
4 miles, 6.5 kilometers, southwest of Ta-tau-ho carries the river into lime- 
stone, which we take to be the Wu-shan formation. The dip observed 
in this limestone, 35° north, and that noted in the schists near Huan-ku- 
t’an, 10° southwest, form a broad flat syncline. We interpret the structure 
as a shallow basin of K’ui-chéu schists on Wu-shan limestone. If the 
