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
Smith Rock State Park the Crooked River (elev. 2600 ft), making the cliffs about 600 feet high. The origin of the Smith Rock name is uncertain. One story, published the Albany "States Rights Democrat" in 1867, states that Smith Rock was named after John Smith, who was Linn County Sheriff and an Oregon state legislator in the 1850s and 1860s. The newspaper article credits Smith with "discovering" the rock. Another story claims the rock was named after a soldier named Smith who fell to his death from the rock in 1863 while his unit was camped nearby. The State of Oregon obtained the park