The Bighorn Basin is a spectacular example of the retreating stage of Noah’s Flood. Very large, differential vertical tectonics in the early retreating stage initiated drainage of Floodwaters into subsiding ocean basins. Concurrent uplift of mountain ranges warped sedimentary layers, and deformation included the movement of the Heart Mountain Slide in the northwest Bighorn Basin. Erosion removed most of the strata from the Beartooth and Bighorn Mountains, but only Mesozoic and early Cenozoic strata were removed from the Owl Creek Mountains. Eroded sediments provided valley fill for the Bighorn Basin. To the west, the Absaroka Volcanics formed by volcanic debris flows. Large "alluvial fans" formed on the east sides of the Beartooth and Bighorn Mountains but were then deeply eroded by north-flowing, channelized Floodwater currents. These currents also eroded several thousand feet of Bighorn Basin fill. Planation surfaces formed on the edge of the surrounding mountains and in the Bighorn Basin, surviving today as erosional remnants. Currents also transported quartzite from central Idaho, redeposited as gravel lags. Pediment and pediment remnants formed, and at least four water gaps were cut.