310 RESEARCH IN CHINA. 
chéu formations appear alternately. Such is probably the case to the 
pass, T’6u-m6n-ssi, but north of that we lose track of the rocks. The 
gray limestone and mica-schists of the vicinity of Liang-ho may probably 
be K’ui-chéu schists in a syncline. The black quartzite of Ta-ho-pa, 
which is probably folded in an anticline or syncline, we identify as the 
characteristic quartzite of the Wu-shan (Carboniferous). Beyond this we 
are unable to extend any inference of age. 
At San-ho-k’6u we came upon gray banded marble which is partly 
schistose, the cleavage planes being coated with biotite and muscovite 
crystals. One or 2 miles north of that village gray gneissic quartzite was 
encountered, but as exposures were not frequent along that portion of the 
road, its relationships to the marble and schists were not determined. 
It is cut by dikes of fine-grained gray granite. The sequence is interrupted 
near Shi-t’ing-ho by large intrusions of porphyritic pink granite, but is 
resumed after a lapse of not more than 2 miles, 3 kilometers, with the 
reappearance of the dark schists and gneisses. A coarse-grained white 
marble is quarried at Ssi-mdéu-ti. The rock is almost gneissoid in structure, 
and contains well-formed tabular crystals of muscovite; in a general way 
it resembles the San-ho-k’6u marble, and it may well be a second occur- 
rence of that member. 
From Ssi-méu-ti to Ts’ai-kia-kuan the complex of schists and mica- 
gneisses continues. All are cut by granitic intrusions of various dimen- 
sions, and the gneiss sometimes shows plicated bands. About half-way 
between the two villages we found what appeared to be a conglomerate- 
schist; the dark biotite-schist contained numerous lenticular bodies of 
quartz, arranged in roughly parallel layers. 
About 2 miles north of Ts’ai-kia-kuan the schist series terminates 
against the great mass of intrusive granite, which forms the central portion 
of the Ts’in-ling range, and extends in a belt 11 miles wide, to Chang- 
k’6u-shi. 
Chang-k’6u-shi to Liu-yué-ho.—The northern part of the high ridges 
of the Ts’in-ling-shan, as far north as Lung-t’an-ssi and Chuang-kia-p’u, 
is composed of gray, greenish, and buff-brown slaty limestone, with thin- 
bedded quartzite and thick beds of gray to black slate. Black coaly slates 
are interbedded with the limestone just below Chang-k’éu-shi, and coal 
was found by von Richthofen* and by Davidt in similar strata not far 
to the west of our route. The limestones themselves closely resemble 
those seen near Ts’6ng-kia-pa (atlas sheet d 5), which we consider Car- 
boniferous. Though generally slaty the rocks are not greatly altered, and 
therefore appear to be much younger than the schists of the Han system, 
* China, vol. 1, p. 566. ft Ibid., p. 628. 
