ECONOMICAL GEOLOGY. 
279 
The principal ore is ehalcopyrite or copper pyrites ; and there is every 
reason to believe that many of the mines recpiire only a fuller develop- 
ment to enable them to furnish large quantities of valuable ores. 
Many of the gold veins are associated with pyritic ores, and in fact 
almost all the North Carolina copper mines in the central counties have 
first been worked for gold, and there are hardly any mines in Guilford, 
Cabarrus and Mecklenburg Counties occurring in the gneissoid and syen- 
itie rocks, which do not show strong indications of copper ores. 
When mining operations receive a new impetus, it is to be hoped that 
this very important fact will be borne in mind, and that no mine should 
be started without sufficient means to develop it at once to such a depth 
that a workable body of copper ores may be reached. 
The general character of these mines is that about at water level, the 
so-called brown gold ores are replaced by quartz richly charged with iron 
pyrites more or less mixed with copper pyrites, the latter increasing as 
the mine deepens, and in many places becoming the only, or the predomi- 
nating ore, and forming a regular copper vein. 
The ores either became poor in gold or the latter could not be extracted 
by the ordinary process, then chiefly in use in North Carolina — Chilian 
mills and arastra — therefore many valuable mines were abandoned, mostly 
before a larger and paying quantity of copper ores had been reached. 
In this formation there is not at present a single copper mine in opera- 
tion, although many look favorable for further development. 
The principal mines which promised to change into copper mines are 
in Guilford countyq the Fisher Hill, the North Carolina, the McCulloh,. 
Lindsay, Gardner Hill, Twin Mines, etc. ; in Cabarrus county, the Ludo- 
wick, Boger, Hill, Phoenix, Orchard, Vanderburg, Pioneer Mills, etc., 
and in Mecklenburg the McGinn, Hopewell, Rudesill, Cathay Mines, etc. 
The cupreous minerals observed in the mines are, near the surface, 
small quantities of native copper and cuprite, the latter sometimes in 
beautiful needles, the so-called chalcotrichite, malachite, rarely azurite, 
chrvsocolla and pseudo-malachite, and in some of the mines chalcocite 
and barnhardtite ; all resulting from the decomposition of ehalcopyrite or 
copper pyrites, which forms the principal ore. Siderite or carbonate of 
iron often forms an important gangue rock.” 
3. Gold. 
The same influences which have prevented mining operations in other 
directions, account also for the fact that but few of the gold mines of the 
state have been re-opened since the war. A few of the more noted mines, 
