Comments on Geologic Parameters
05 Percent Shale:
Percent shale of the Fox Hills Sandstone is directly inferred from the percent-sandstone map of Lewis and Hotchkiss (1981). Greatest percent-shale values occur in the south part of the basin.
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.