Stratigraphic Cross Sections of the Lewis Shale in the Eastern Part of the Southwestern Wyoming Province, Wyoming and Colorado

Three stratigraphic cross sections A–A', B–B', and C–C' were created for the Lewis Shale and associated strata in the eastern part of the Southwestern Wyoming Province of Wyoming and Colorado. The cross sections highlight 15 clinothems within the Lewis Shale, Fox Hills Sandstone, and Lance Formation progradational system (also referred to as the Lewis Shale system). Additionally, the cross sections indicate that multiple source areas were active at the same time during deposition of the Lewis Shale. Specifically, the north-to-southeast cross section A–A' demonstrates that the northern, sand-rich source was being deposited and onlapping onto an older, southern, mud-rich source.