. Bulletin . nblende, biotite, chlorite, cal-cite, and magnetite, with a few scattered grains of zircon and hornblende occurs in two varieties, one green in color, and the otheryellowish-brown. The latter, which is subordinate in amount, has ]iarallclextinction and is present in long ragged prisms. It is one of the ortho-rhombic amphiboles. The other minerals present no unusual character-istics. The drive connecting the Sulphur and IT. Y. shafts exposes anoffset of 10 to 15 feet in the course of the vein just north of the Sulphurshaft, the space between being occupied by a zone c
. Bulletin . nblende, biotite, chlorite, cal-cite, and magnetite, with a few scattered grains of zircon and hornblende occurs in two varieties, one green in color, and the otheryellowish-brown. The latter, which is subordinate in amount, has ]iarallclextinction and is present in long ragged prisms. It is one of the ortho-rhombic amphiboles. The other minerals present no unusual character-istics. The drive connecting the Sulphur and IT. Y. shafts exposes anoffset of 10 to 15 feet in the course of the vein just north of the Sulphurshaft, the space between being occupied by a zone containing numerouslenses and irregular masses of quartz. At the shaft the vein is standingnearly vertical. The sketch given in fig. 8 shows the distribution andshape of the quartz masses exposed on the east side of the drive about 15feet north of the shaft. The country rock here is the dark variety ofgneiss, and is much folded and contorted. 130 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. N. E. -^S. Pig. s.—^Vertical section showing distribution of vein quartz in a sheared zone atthe Young American Mine. S. E. ^N. W.
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