Fig. 2. Sheep Creek Wash and Oro Grande Wash and their associated fan deposits in the western Mojave Desert, San Bernardino County, California (adapted from U.S. Geological Survey, 1:250,000 San Bernardino quadrangle and modified from Weldon, 1985). Core samples were collected from the lower reaches of each wash. Boreholes L and L-1 were drilled directly in the channels, while L-2 and F were drilled into the adjacent fan surfaces.