454 S. B. Christy— Genesis of Cinnabar Deposits. 
men “ Hanging Wall,” and 
The 
deposit of cinnabar. 
Associated with the cinnabar are found dolomitic crystals of 
pearl spar, iron pyrites, chlorite, and extremely seldom crystals 
of quartz. Another notable fact is the occurrence of a bitu- 
minous substance resembling idrialite. This substance 1s 
wrongly stated by Mr. Kuss, in the memoir above cited, to be 
“ be bed = * 
external appearance of a soft bituminous coal, but when heated 
melts and flows like bitumen. Ordinarily it is found in the 
liquid condition, and flows from the drusal cavities in which it 
is contained when they are opened. When strongly heated it 
gives off highly inflammable hydro-carbon vapors, and leaves 
an intumescent coke which is very light and fragile, and burns 
impregnated with a hydro-carbon more like petroleum, as in 
the 1,500 and 1,600 feet levels of the Randol shaft. — : 
In that part of the mine known as the Cora Blanca, there is a 
_ sheet of dolomitic limestone which extends from the top to the 
- bottom of the mine. This lies immediately beneath the Alta 
