The other sediments are generally less than 20 feet thick. The surficial materials range from coarse gravel to clay and peat. They affect the movement of ground water from the surface into underlying bedrock aquifers, and are aquifers themselves in places. They also provide foundation support for structures, and supply sand and gravel for construction purposes. All BND information for a coverage is stored in the BND file.
Tics are the registration or geographic control points for a coverage.
All tic information for a coverage is stored in the TIC file. NAME OF DATA hunsrf24 2.1.1. These maps are based on fieldwork and airphoto interpretation by Stanford and Witte between 1987 and 1990. Data mylars were digitized by Maryann Scott. The contacts coverage was built by scanning mylar separates of the quadrangle maps using a CalComp ScanPlus II scanner set at 400 dpi resolution.