Mining Terms. 173 
channel claims, except lodes in place. For special mean- 
ing under the law, see Section 2329 U. S. Rev. St. 
Prat. A small chamber on the side or sole of a 
level where it intersects a shaft, made to facilitate 
dumping. Where it is cut in the sole it is called a trip- 
‘plat. Corn. 
Pocket. A detached ore body; a nest of ore. 
Pocxety. A term applied to a mine where the pay 
ore occurs in small detached bodies with intervals of 
poor ore or barren material. The word implies a slur 
on the mine. Paull v. Halferty, 9 M. R. 149. 
Porpuyry. A general term including such plu- 
tonic rocks as exhibit well-formed crystals, usually of 
feldspar, in a finely granular or compact base of the 
same. Gr. 
PorRPHYRITIC GRANITE. A base of granite con- 
taining prominent crystals of feldspar. 
Prospecting. A search for deposits, applied both 
to the seeking of undiscovered veins and to the investi- 
gation of the value of known veins by exploration. 
Pyritres. (White) A sulphide of iron. (Yel- 
low) A sulphide of copper. A bright, crystallized, 
metallic-looking and very common gold-bearing ore, 
usually low-grade and spoken of in common parlance 
as the “Iron.” Gr. 
Quarry. Any open work in rock on a plan of 
excavating the entire mass, as distinguished from work- 
ing a seam or vein by shafts or aproaches under cover. 
Quartz. Siiica. A constituent of granite. The 
free gold of California being found in quartz, the word 
was applied to the gangue of such lodes and so to other 
forms of vein matter, until it is now used vaguely to 
mean the ore, the float, the gangue, or that part of the 
gangue which indicates the pay streak. In the Acts of 
_ Congress it is used with the word rock (quartz or other 
rock) in the sense of pay rock. 
QuARTzITE. A metamorphosed sandstone. A rock 
containing usually about 98 per cent. silica, with a small 
percentage of foreign materials, principally iron. 
