Geology and ore deposits of the Metaline zinc-lead district, Pend Oreille County, Washington

Abstract

The Metaline zinc-lead district, the most important mining district in the State of Washington, is an area of about 75 square miles in Pend Oreille County, which adjoins British Columbia to the north and Idaho to the east. The region is brushy and heavily forested. The main topographic feature is the valley of the northward-flowing Pend Oreille River, a tributary to the Columbia River. The Pend Oreille River is bordered by two conspicuous terrace levels; beyond these terrace levels lie somewhat smoothed hills and mountains. The highest point in the district is Boundary Ridge, 5,219 feet in altitude; the lowest point, about 1,750 feet, is at the Pend Oreille River where it enters Canada. The Cordilleran ice sheet covered the entire area, and erosional and especially depositional glacial features, such as till, glaciofluvial gravels, and silty lake deposits, are common.