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
Brazos Bend State Park maintenance of a natural landscape. In 1984 the Park was officially opened to the public, its lands having been donated to the state several years previously. In 2009, the Park celebrated its 25th Anniversary with a variety of special events and recognitions. Today the Park is run by the Texas Parks and Wildlife Department, with the assistance of an active non-profit volunteer organization. Although it contains recreational day-use areas (including a dining hall, campground, and picnic areas) Brazos Bend is by primary character a natural park. Its recreational opportunities revolve around enjoyment of its diverse ecosystems and species. Popular activities