Several other formations were also created but were mostly eroded away following two major periods of uplift. The Laramide orogeny affected the entire western part of what would become North America starting about 70 million to 50 million years ago. This event helped to build the Rocky Mountains and in the process closed the Cretaceous Seaway. The Straight Cliffs, Wahweap, and Kaiparowits formations were victims of this uplift. The Colorado Plateaus were uplifted 16 million years ago and were segmented into different plateaus, each separated from its neighbors by faults and each having its own uplift rate. The Boat Mesa Conglomerate and the Sevier River Formation were removed by erosion following this uplift.