1. Resource potential for crushed stone, sand and gravel, and clay in the Charlotte 1° x 2° quadrangle, North Carolina and South Carolina Yale Public content 1986. 2002-06-01T04:00:00Z. 2015-06-22T20:03:02Z. Geological Survey (U.S.). The Survey. English. cartographic image. Public. North Carolina, South Carolina, North Carolina., and South Carolina.