72 
Monazite and Monazite Mining [ November 
ture caused by the more or less separate occurrence of certain 
minera's arranged in parallel streaks, with a roughly parallel 
orientation of the crystals or grains of each mineral. The princi- 
pal features of the banding consist of larger quartz streaks with 
several smaller ones and individual grains in a regular biotite 
schist. The other minerals occupy various positions and show 
diverse relations to the minerals of these bands and to each other. 
The feldspar is porphyritic and occurs chiefly in individual crys- 
tals, some of which are of considerable size. A number of the 
feldspar phenocrysts are small bodies of pegmatite in themselves. 
The feldspar phenocrysts replace the other minerals. Graphite 
occurs in large amounts with biotite, though it is associated with 
nearly every other mineral of the rock. Where present, muscovite 
is chiefly associated with the feldspar. Monazite seems to be 
indiscriminately scattered through the rock, included in or asso- 
ciated with all the foregoing minerals. Though generally free 
from inclusions, it is not invariably so, and in one case a plate of 
graphite was observed within a monazite crystal. All the minerals 
observed in the rock, with the exception of zircon, have been noted 
as inclusions in the feldspar phenocrysts. 
In microscopic sections cut from specimens from one of the ore 
streaks, the minerals described above were observed, together with 
some iron staining. The feldspar is principally orthoclase and 
microcline, partially kaolinized. The quartz is plainly secondary, 
and occurs in bands or streaks or grains parallel with the schis- 
tosity of the rock. In some places the quartz has been deposited 
in the fracture or between the grains of other minerals; in others 
it replaces or includes fragments of such minerals as biotite and 
graphite. 
Gas cavities and inclusions of very fine acicular needles, pro- 
bably rutile, are abundant in the quartz. Biotite occurs in inter- 
woven laths and crystals roughly parallel to the banding of the 
rock. The pleochroism of the biotite is light yellow-brown to 
greenish brown or dark purplish red. Graphite occurs as plates 
and laths, in general lying parallel to the banding of the rock. 
Some of it is interbanded and even interleaved with biotite; else- 
where the plates are turned across the foliation. In one section a 
lath of graphite was observed inclosed in quartz which filled a 
