POTD October 14, 2013: St. George basin, Washington County, Utah

St. George basin, Washington County, Utah
Photographer: Robert F. Biek

Ruins of the Harrisburg town site, established by Mormon pioneers in 1861, consist of blocks of Early Jurassic-age Springdale Sandstone, which a mile to the north is the main ore-bearing horizon of the Silver Reef mining district. The mining district is famous among geologists for its uncommon occurrence of silver ore in sandstone. In the distance, the Pine Valley Mountains tower 7,000 feet above the surrounding red-rock country.