|Fox Hills - Lower Hell Creek, Powder River Basin
The principal source for mapping formation depth of the Fox Hills Sandstone in the Powder River Basin is Lewis and Hotchkiss (1981), who presented a structure map on the top of the Fox Hills Sandstone; it reaches a maximum depth of more than 3,000 ft (>910 m) in the steeply dipping, western part of the basin, west of Gillette. We subtracted the subsea elevation of the formation top from the gridded land-surface elevation from a DEM generated from Digital Terrain Elevation Data (National Imagery and Mapping Agency, 2000) to calculate depth to top Fox Hills.
Fox, J., and Higley, D., 1987, Structural at the Base of the Upper Cretaceous Fox Hills Sandstone, Power River Basin, Wyoming and Montana. USGS OFR 8
Lewis, B. D., and Hotchkiss, W. R., 1981, Thickness, percent sand, and configuration of shallow hydrogeologic units in the Powder River Basin, Montana and Wyoming: U. S. Geological Survey, Miscellaneous Investigations Series, Map I-1317, 6 sheets.
National Imagery and Mapping Agency, 2000, Digital terrain elevation data (DTED Level 0), http:/www.gisdatadept.com.