ECONOMICAL GEOLOGY. 
2S9 
Native silver has been observed with chalcocite or copper glance at 
Clap Creek mine, in Wilkes county, and at the Asbury vein in Gaston 
■county. 
The only real silver mines of North Carolina are ore beds of zinc 
blende, mixed with galenite, in the argillaceous and talcose slates. The 
tvpe of these is the old Washington mine, now Silver Ilill, in Davidson 
county, which was discovered in JS38. Near the surface it formed a bed 
of carbonate of lead, having in many places films and plates of metallic 
silver disseminated through the mass of the ore. These ores were easily 
reduced, and produced handsome returns to the owners. This was, how- 
ever, but of short duration. The undecomposed ores, which were a very 
fine grained mixture of brown zinc-blende and argentiferous galenite, were 
soon reached, and presented great difficulties in the extraction of the pre- 
vious metals. 
When I was at the mine, about 22 years ago, an analysis of an average 
sample of between 2000 — 3000 tons of ore gave me about 45 per cent, of 
zinc, 21 per cent, of lead, about 8 ounces of silver per ton, with minute 
■quantities of copper and gold. If the Philadelphia owners had abided by 
my advice, viz., to work the ores for zinc, and extract silver, copper and 
lead from the residues, they would probably still be in possession of this 
valuable mine. 
The ore bed is large, and in one place lias had a thickness of about GO 
feet. 
Occasionally it contains very rich spots, with native silver in lumps and 
filiform masses, or disseminated through the ore with argentite or highly 
argentiferous galenite; and besides these minerals this mine has furnished 
the most magnificent cabinet specimens of cerusite, pyromorphite, etc. 
The mine is now 650 feet deep, and the ore is greatly mixed with slate. 
The purer masses are kept separate; the slaty ore is crushed and separa- 
ted by buddies, etc., and the huddled ore is roasted and shipped to New 
York for the manufacture of the so-called Dartletts’ white lead. The 
production of this mine is now about 400 — 500 tons per month. 
Very similar ore is found about six miles northeast of Silver Ilill. The 
vein has not been developed, and the work done at Silver Valle} 7 has not 
been productive. 
The Hoover mine, about six miles from Silver Hill, contains galenite, 
in a more coarsely crystalline variety, in a calcareous veinstone, and the 
Doss mine, two miles distant, has furnished handsome cabinet specimens 
of galenite in quartz. 
The McMakin mine, about 1-J mile southeast from Gold Hill, is a very 
interesting one ; the principal vein is a large vein of zinc-blende in tab 
