Abstract: Multiple deep passes crossing the present-day east-west continental divide and numerous south-oriented tributaries flowing to the present-day north-oriented Gallatin, Madison, Jefferson-Beaverhead-Red Rock, and Missouri Rivers provide evidence the Gallatin, Madison, and Jefferson-Beaverhead-Red Rock valleys originated as diverging channels in a large-scale south-oriented anastomosing channel complex that was subsequently reversed to form the present-day north-oriented Gallatin, […]