20 RESEARCH IN CHINA. 
and in other phases chlorite is the dominant dark mineral. There are 
also variations in texture, from fine-grained varieties in which the banding 
is minute, to coarser varieties containing prominent eye-spots of feldspar. 
There are schists, most of which are dark greenish or blackish rocks 
composed of quartz and hornblende, with or without biotite. Some of 
the varieties are not well cleaved, and the fracture surfaces are brilliant 
with the shining hornblende crystals. Chloritic greenstones occur, but 
rarely. 
The rocks of this first group are so thoroughly metamorphosed and so 
complexly folded that it is difficult to study their relations to each other. 
The schists have the composition of igneous rocks, but the available data do 
not suffice to preclude the idea that they may be in part of sedimentary 
origin. The gneiss is probably an ancient granite, which was intruded 
into the schists and subsequently metamorphosed. ‘The relation was 
not satisfactorily determined in the field, but the schists were frequently 
found included in the gneiss in the form of irregular bodies, as if they had 
been imbedded in the granite at the time of intrusion. 
Some of the biotitic schists occur as dike-like masses traversing both 
the gneiss and the older schists (see Fig. 2); evidently they represent 
basic intrusions later than the gneiss. 
GRANITES. 
In many exposures of the Pre-Cambrian nothing is found but a 
medium-grained red granite, composed largely of orthoclase, quartz, and 
biotite. In the T’ai-shan and 
also in other localities, there are 
pale gray granites which lack 
the red feldspars; and greenish 
varieties which owe their color to 
an unusual amount of epidote and 
chlorite. Hornblende is lacking 
in all of the T’ai-shan granites. 
Most of these rocks are fine- 
grained and thev seldom exhibit Fic. 3 (Blackwelder) —Ch’ang-hia, Shan-tung. Massive 
4 a red granite including fragments of ancient gneiss 

3 FEET 
a distinctly gneissoid structure. crossed by veins of pegmatite. a= banded gray 
Microscopic examination, how- gneiss; 6 = pegmatite vein; c= red granite. 
ever, shows that they have suffered more or less severe deformation. 
The granites occur either in large batholitic masses, or in dikes which 
emanate from these central bodies. The dikes cut across the schists and 
gneisses in such a way as to show clearly that the granites are intru- 
sives of later age, probably Algonkian. Near the borders of the granitic 
