In March 1864 more than 1400 of the tribespeople started from here on the Long Walk to Bosque Redondo. At about the point where N12 intersects Navajo 7, the road veers back into New Mexico and stays in that state for seven miles. Enjoy the scenery for a while. Enter Navajo, New Mexico. There is another less obvious diatreme at the North end of town, which has apparently been mined for road fill.
Red Lake is on the left.
Black Creek, the source of the water in Red Lake, flows south through Window Rock, eventually cutting across the Defiance Monocline to join the Rio Puerco. Just beside the road ahead on the east is Green Knobs, a large diatreme neck that has intruded through the Triassic Chinle Formation. This rock is mostly kimberlite, the green color coming from the mineral olivine. Kimberlite is the source of diamonds in South Africa, Russia, Arkansas, Colorado, and so on. In the Four Corners, the kimberlite contains only tiny pieces of garnet and, occasionally, olivine in the form of peridot.