Nacimiento Formation Nacimiento Formation The Nacimiento Formation is a sedimentary rock formation found in the San Juan Basin of western New Mexico (United States) and named for the Nacimiento Mountains. It is a heterogeneous nonmarine formation composed of shale, siltstone, and sandstone, deposited in floodplain, fluvial and lacustrine settings, and made up of sediment shed from the San Juan uplift to the north and the Brazos-Sangre de Cristo uplift to the east. It was deposited mostly between ~64.5 and ~61 million years ago, during the early and middle Paleocene. The climate was humid and warm to hot. This unit interbeds with the
Pink Cliffs cliffs are pink- and red-colored Claron Formation limestones, forming the upper riser of the Grand Staircase (which descends southward to the Grand Canyon in Arizona). The Pink Cliffs, as well as the other layers of the Grand Staircase, were named by geologist Clarence Dutton in the 1870s. While it is not an uncommon belief that the extent of the Pink Cliff is limited to the Bryce Canyon National Park area (being one of the best and most popular areas to view the cliffs), geographically, the cliffs actually extend well beyond the national park, forming a rough, but wide, "U" shape