Madison Limestone or Group - Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite). Darby Formation - Yellow and greenish-gray shale and dolomitic siltstone underlain by fetid brown dolomite and limestone. Three Forks Formation - Yellow and greenish-gray shale and dolomitic siltstone. Jefferson Formation - Fetid brown dolomite and limestone. Beartooth Butte Formation - Red sandstone, limy siltstone, and limestone. Occurs only in the Beartooth Mountains.