428 RESEARCH IN CHINA. 
all slightly elongated in a common direction. Under the microscope these 
spots appear to be grains of scapolite which have been rounded by granula- 
tion and elongated in the plane of schistosity. 
They are filled with inclusions of magnetite, quartz, and tourmaline, 
and are therefore believed to be of later origin than the schistose mass in 
which the tourmaline grew.* Along irregular cracks the scapolite alters 
to micaceous material resembling kaolin. The pitted surface of the 
weathered schist indicates how rapidly the scapolite is dissolved when 
exposed to the air. 
Garnet-staurolite schist, No. 95.—A thick mass of dark garnet schist 
separates the white marble of the Shang-ho-miau section from the body of 
augen-gneiss which lies south of it. It appears probable that the augen- 
gneiss is a metamorphosed intrusive in the Wu-t’ai system, and on this 
hypothesis the garnet schist may represent the contact phase of the sedi- 
mentary strata. Our specimen was taken in the lower layers of the schist 
adjacent to a dike of schistose greenstone. 
A silky gray schist studded with small red garnets and larger, though 
much less conspicuous, staurolites. The cleavage is irregular and the 
laminz are lumpy with the porphyritic crystals. 
The rock is so thoroughly schistose that none of its original components 
may now be recognized. Much of it consists of a schistose mass of quartz 
and feldspar, with minute flakes of biotite, muscovite, and iron ores. 
In this ground are embedded tertiary crystals of red garnet, biotite, 
staurolite, and tourmaline. The garnet is idiomorphic and includes many 
small bodies of iron oxides, etc. The very ragged crystals of staurolite are 
of much larger size, but are fewer in number. 
A number of distinct episodes in the history of this rock may be deci- 
phered from the thin section (Plate LVI, Fig. F). From the analogy of 
other garnet schists we infer that the original sedimentary rock was a pelite 
of complex chemical constitution. This original material has completely 
recrystallized during metamorphism; new minerals resulted, and all new 
structures were adjusted to the stresses. At a later time, while still in the 
zone of flowage, the rock developed crystals of heavy silicates such as biotite, 
garnet, and staurolite. They grew in situ, absorbing the earlier minerals 
of the schist as they did so. A recurrence of differential movements slightly 
deformed these porphyritic bodies. The garnets and biotites lie in eye- 
spots bounded by shear-zones, while the large ragged staurolites have been 
granulated and dragged out into streaky forms. A much later episode of 
alteration, this time in the katamorphic zone, permitted the formation 
of a little chlorite from biotite and garnet. 

* A fuller description of the scapolite is given in the description of No. 158, p. 427. 
