STRATIGRAPHY OF CHI-LI AND SHAN-SI. 103 
noted. Farther to the west, in the region about Féu-p’ing-hién, there are, 
in addition to the gray varieties, granite-porphyries of a decidedly pinkish 
tinge. These also occur in dikes 3 to 10 feet, 1 to 3 meters, in thickness. 
The aplites are dense gray-white rocks, which occur in thin sheets and 
dikes. They are evidently associated genetically with the granite-porphy- 
ries, for in one instance a thin aplite sheet was traced into a larger dike of the 
blue-gray holocrystalline rock, and was thus proved to be an apophysis of 
the latter. Some of the aplites are flecked with minute blotches of epidote 
and garnet. 
The feldspar-porphyries are light brown, often reddish, rocks, which 
contain stout phenocrysts of feldspar, and near Féu-p’ing-hién the dikes 
usually exhibit quartz crystals also. 
Dioritic rocks, hornblende-porphyries, and greenstones in considerable 
variety are frequent in the region from T’ang-hién to Féu-p’ing-hién, 
occurring as dikes and sheets of rather large dimensions wherever the basal 
complex is exposed. One dike of greenstone (dioritic?) in the southeast 
end of the mountain west of Wan-hién has a maximum breadth of 400 feet, 
120 meters. The schistose greenstones appeared first just west of Féu- 
p’ing-hién and became more abundant as we approached Wu-t’ai-shan. 
Dikes 100 feet, 30 meters, thick are frequent. 
The intrusives mentioned in the last paragraphs do not show equally 
the effects of metamorphism, and probably are not all of the same age. 
The feldspar-porphyries along the Sha-ho appear to have suffered no meta- 
morphism other than weathering. They are plainly subsequent to the 
last episode of severe deformation, and are probably of Post-Sinian age. 
Among the porphyries and aplites near T’ang-hién the effects of mashing 
and partial recrystallization are obvious under the microscope, but are not 
revealed megascopically. They are distinctly more deformed, however, 
than the feldspar-porphyries just described. Of the greenstones and basic 
porphyritic rocks, some are notably metamorphosed, while others appear 
to have undergone little change. Many of the greenstones are plainly 
schistose amphibolites, but their origin from basaltic intrusives is, never- 
theless, scarcely questionable. 
The complex is everywhere crossed by veins of pegmatite and quartz, 
which are in large part earlier than most of the smaller igneous intrusions. 
It is probable that most of the pegmatites are genetically akin to the granites, 
although we have no definite data on this point. In addition to the com- 
moner pegmatites, which consist of coarse crystals of quartz and orthoclase, 
it is not uncommon to find others in which hornblende or biotite are promi- 
nent constituents; most of the hornblende pegmatites occur west of Féu- 
p’ing-hién. 
