464 RESEARCH IN CHINA. 
of the epoch of mass-mechanical change, the rock has been subjected to 
the tensile strains of which we have evidence in the numerous sharp fissures 
which are now sealed with vein quartz. 
White aplite, No. 127.—This intrusive was found about 7.5 miles, 12 
kilometers, above Shi-ts’iian-hién, in the canyon of the Han river. At 
that point it is in contact with metamorphosed dark limestones and it 
separates these sedimentary rocks from the mass of greenstone which lies 
to the westward. Its relation to the limestones is evidently that of a 
subsequent intrusion, but the contact between the felsite and the green- 
stone was not observed. It is possible that this acid rock is genetically 
connected with the greenstone, and that it was developed from the basic 
magina by the process of differentiation which occurs in fluid lavas. It is 
more probable that the felsite is a dike of later age than the greenstone 
and that it was intruded along the contact between the basic rock and the 
sedimentary strata. 
This is a stony aphanitic rock which, on fresh surfaces, is greenish- 
white, but which weathers to a buff color on account of a small amount of 
ferruginous material which it contains. The rock exhibits no definite 
structure, but in the particular situation observed it is traversed by numer- 
ous closely spaced joints, so that it was not easy to obtain a specimen of 
the desired size. 
The thin section shows that the rock is composed of a finely granular 
ground-mass composed entirely of colorless quartz and feldspar. In these 
are embedded a few moderate crystals of orthoclase, but quartz is not 
represented among the phenocrysts. A closer inspection of the slide shows 
that there are parallel layers in which the constituents are alternately 
either coarser or finer than in adjacent layers, suggesting incipient schis- 
tosity. 
The phenocrysts of orthoclase are filled with secondary inclusions of 
micaceous minerals. During the deformation which the rock has suffered, 
some of the phenocrysts have been fractured and the fragments more or 
less displaced. The fissures thus produced are now sealed by veins of fresh 
feldspar or sometimes quartz and feldspar together. About the edges 
of the phenocrysts, and particularly before and behind the crystal with 
reference to the lines of banding, granulation of the feldspar has taken 
place, and the detritus thus produced has in large measure recrystallized 
in the form of fresh interlocking grains free from inclusions. The corners 
of the ‘‘eye-spots’”’ are frequently filled with new quartz rather than feld- 
spar. 
The ground-mass is made up of minute irregular but rounded grains 
of quartz and clear limpid orthoclase. The feldspar is present in somewhat 
greater abundance than the quartz. With the exception of certain masses 
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