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 yearly offerings include the A Simple Christmas celebration, Prairie Heritage Days, and the July 4th Bike Parade. The Park also hosts a variety of activities put on in conjunction with other entities, including the Christmas Bird Count and the Butterfly count, undertaken as part of the Audubon Society and North American Butterfly Association's national efforts, respectively. Brazos Bend State Park's Christmas Bird Count effort is routinely in the top 3-4% of the over 2000 Counts taking place in North America. The park is also home to the George Observatory (code: ), a satellite facility of the Houston Museum of Natural