Cincinnati Paper - Note on Iron-ore Deposits in Pitkin County, Colorado

I have observed three deposits of iron ore in Pitkin County, which present unusnal characteristics, and wliich seem to throw some light upon the genesis of iron ores under certain conditions. They occur in the precipitons mountain ranges, forming spurs on the Pacific slope of the main continental backbone. The first is a body of limonite, lying upon the side of a high mountain, which forms part of the base of Hayden's Peak. This limonite forms a sheet of considerable area, and is thin at the edges, and about 3 feet in thickness in the central portions. It is conformable with the slope of the mountain side, and rests upou the eroded rocks, but is not comformable to them. The ore is laminated and shaly in texture, and has the physical characteristics of the hard limonites, such as are found in the Marquette District, Lake Superior. It is covered with loose earth and rocks, from 1 to 2 feet in thickness. Much of the ore is filled with impressions of' spruce leaves, such as are found in the forests now covering the slope of the mountain. In the rocks forming the mountain, iron pyrites occurs in bodies, and this limonite probably owes its origin to such a body not far distant. Not far up the mountain large masses of conglomerate are now forming, the cementing material being a similar hydrated oxide of iron. The iron is