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
Uhangri Formation Uhangri Formation The Uhangri Formation, located at the Uhangri Dinosaur Fossil Site, is a geological formation from which fossil pterosaur tracks have been recovered near Haenam-eup, Jeollanam-do, South Korea. The Uhangri Dinosaur Fossil Site area was originally covered by ocean, uncovered when Lake Damsuho, and surrounding area, was created by the construction of the Geumho Tide project. Lake Damsuho has cliffs that are 3–4 meters/10–13 feet high, stretching about 5 kilometers/3.1 miles, made up of sedimentary rock formed during the Cretaceous age. Embedded in the rock formations around the lake are fossilized footprints of dinosaurs, pterosaurs and water birds that