368 
HUBBARD AND CRONEIS 
Iron 
Iron ore has been mined in Giles County, and will, in the 
future, constitute a more important economic resource than it 
has in the past or does at present. The ores may be divided into 
three classes : Those found in the Oriskany horizons, the Clinton 
or Red fossil ore of the Rockwood and the ores found in the 
lower Paleozoic limestones. 
The Brown iron ore is the type usually found in the Oriskany 
measures. Boyd-'^ estimated that ten per cent, of these rocks 
were iron, but the deposits are of such a local nature that this 
estimate seems much too high. The most conspicuous beds are 
found on Buckeye, Butt, Salt Pond and Flat Top mountains. 
There is also a large deposit on Wolf Creek Mountain, which 
Boyd thought would yield 300,000 tons of ore, which would 
run over sixty per cent, metallic iron. Boyd was rather 
prone to exaggerate and but little has been mined here. At 
Interior, some mining of Brown ore in Oriskany measure has 
recently been done, and since the railroad has solved transporta- 
tion problems, it seems likely that more ore will be mined in 
the future, as the reserves here are quite large. 
The source of these ores has been explained in the discussion 
of the Stange mine. The Devonian was a period during which 
much iron was deposited,-® as is shown by the fact that shales 
overlying the Oriskany sands will run five per cent, iron con- 
tent. The concentration of these ores in fracture zones in the 
lower sandstones is thought to be the origin of the local Oriskany 
ores. 
Hematite ore is found in the Clinton (Rockwood) formation 
wherever it is exposed in Giles County. The ore is usually the 
richest in the lower layers just over the Clinch. This is especially 
true where the Rockwood is the ridge maker, as in these cases 
the iron of the upper layers has been leached out and concen- 
trated in the fractured lower layers, which overlie the nearly 
impermeable quartzite below. 
The ore is both fossil and granular in type. The fossil ore is 
made up of aggregates of broken fossils, which were originally 
calcium carbonate, but which have now been replaced by ferric 
oxide, some of which was always present in the formation, prob- 
Boyd, C. R., “Resources of Southwest Virginia,” pp. 144. 
^ Emmons, W. H., “Principles of Economic Geology,” pp. 295. 
