I1o RESEARCH IN CHINA. 
In describing the different members of this group, we shall begin at 
the southeast end of the section, which is probably the base. The sup- 
posed basal member has already been mentioned in connection with the 
Pre-Wu-t’ai unconformity. ‘This is a pale grayish or pinkish quartzite 
(stratum 3) which is spotted with crystals of red orthoclase often several 
millimeters in breadth. As mica is sometimes present, though in relatively 
small amounts, hand specimens might be mistaken for quartzose granite, 
but in large masses the stratification is obvious. The microscope reveals 
the fact that the original arkose has been completely cemented and 
severely deformed, the original grains having been partly demolished and 
recrystallized. 
The feldspathic quartzite was again observed along the eastern tribu- 
tary of the T-ai-shan-ho, 4 miles, 6.5 kilometers, south of Shi-tsui (Fig. 20). 
There it lies adjacent to an augen-gneiss identical with that which interrupts 
the succession in the T’ai-shan-ho section. The quartzite lies upon layers 
of dark biotite-schist, which are interbedded with a stratum of pink-and- 
green amphibolite composed of actinolite and calcite—probably an altered 
limestone. ‘This is associated with white sericite-schist. The sedimentary 
origin of these schists can hardly be questioned. It is therefore probable 
that at this point the feldspathic quartzite is not the lowest member of the 
stratified series, although it is undoubtedly near the base. 
In the section east of Shi-tsui the feldspathic quartzite grades upward 
into a pink quartzite containing mica, but not much feldspar. Toward the 
top thin layers of mica-schist are interbedded, and by a gradual transition 
the rock comes to be largely a mica-schist including layers of pink quartzite. 
The schist is a massive rock, which cleaves with considerable difficulty and 
weathers like a hard argillite. The cleavage planes are sprinkled with 
purplish-brown biotite, which is frequently aggregated into flat disks 1 or 
2 centimeters in breadth. Some of the layers are rich in red garnets 
while others contain scapolite and staurolite. Following these mica-schists 
and forming the south slope of the canyon at Shi-tsui, occur brown-banded 
quartzites which are nearly uniform in character. The sequence up to this 
point includes about 3,000 feet, 900 meters, of strata, forming beds num- 
bered 3 to 10. The river bed makes a gap of several hundred feet in our 
section. The concealed rocks are probably soft mica-schists. 
On the north side the quartzites are absent, and to the northwest 
we crossed for 3 miles, 5 kilometers, a succession of gray mica-schists and 
fine-grained mica-gneisses. The schists are at first biotitic, but muscovite 
becomes a prominent constituent near the northern end of the section. 
Thin beds of chlorite-schist occur not infrequently throughout the section. 
About 2? miles, 4.4 kilometers, above Shi-tsui, the schists contain a rather 
