The Eagle Mountains are in eastern Riverside County. Although this district is best known as a major source of iron ore, it has also yielded some gold, silver, lead, and copper. The principal source of gold has been the Iron Chief mine, which has an estimated total production of $150,000. The gold and base metal deposits occur either as replacements along limestone-granite contacts or in fissure veins in either granitic or metamorphic rocks.
Tucker, W. B., 1945, Riverside County, Iron Chief mine: California Div. Mines Rept. 41, p. 136.