302 RESEARCH IN CHINA. 
Nan-kiang cuts a gorge, which is narrower than the canyon immediately 
above or below. These rocks are dark impure limestones, sometimes 
siliceous, but usually argillaceous. They are associated with dense buff 
dolomites, black and gray slates, and anthracite coal, which is mined in 
the vicinity of Pai-kiu-hia from seams in the black limestone. In the 
same locality intrusions of gabbro, similar to those mentioned in the last 
paragraph, break through the hard limestone as well as the slates. We 
regard this outcrop as the lower massive part of the Wu-shan, which 
occurs in the same relation north of Chén-p’ing-hién. The dip near Pai- 
kiu-hia is steep to the north or vertical. 
Slaty black strata extend the sequence to the forks of the Nan-kiang 
(atlas sheet d 5), west of which we particularly noted an outcrop of buff 
limestone, strike NW., dip 50° NE., which strikingly resembles a lime- 
stone of the Hei-shui series of the northern Ts’in-ling-shan. It will be 
ee: : 
2s 
AO. ea Wil: 
eo yh Bm 
Soe be i CELE Wilf ry 
2, LAY 
Fics. 63 AND 64.—Folds in Carboniferous argillites near Ku-niu-tu, Shen-si. 

seen that the strike is here nearly parallel to our course, but it is not per- 
sistent in any one trend. It ranges from east-west to north-south, and 
the dip is accordingly now north, now east. Going north-northwest we 
follow the Wu-shan argillite nearly to Pa-kua-miau, and remain near the 
base of the formation all the way. In the vicinity of Tséng-kia-pa the 
blue-gray limestones and slates contain quartz-mica-schists, in which 
small, but workable, seams of anthracite occur, and northwestward coaly 
black slates and siliceous argillites continue. 
About 3 miles, 5 kilometers, north of Ts6ng-kia-pa blue-black siliceous 
argillite lies upon a greenish conglomerate-schist. The rock is a chlorite- 
sericite-schist, in which are imbedded distorted pebbles of white quartz, 
bits of feldspar, and limestone. None of the constituents is recognizable 
as to age. There is no doubt but that this conglomerate lies in contact 
with the Wu-shan (Carboniferous) limestone, but we are not sure whether 
above or below it. If above, it is at the base of the Permo-Mesozoic series, 
a horizon at which we are led to expect an unconformity on account of 
the abrupt change in physical conditions. If below the Wu-shan, it is 
at the base of that formation in contact with the Sin-t’an shale. Further 
south on the Ta-ning-ho we observed apparent conformity at this horizon, 
