The Entrada Sandstone was deposited in the Colorado Plateau, Colorado, USA, during the Jurassic Period somewhere between 180 and 140 million years ago. The Colorado Plateau, also called the Colorado Plateaus Province, is a physiographic region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. ... State nickname: The Centennial State Other U.S. States Capital Denver Largest city Denver Governor Bill Owens (R) Official languages English Area 269,837 km² (8th)  - Land 268,879 km²  - Water 962 km² (0. ... The Jurassic period is a major unit of the geologic timescale that extends from about 200 million years BP at the end of the Triassic to 146 million years BP at the beginning of the Cretaceous. ...

The sand grains and siltstones of tidal mudflats, beaches and sand dunes make up the 3 members of this rock formation: the Dewey Bridge, Slickrock and Moab members.

The lower unit, comprised of siltstones, sandstones and mudstones, is the Dewey Bridge member, named after the type locality at Dewey Bridge, Utah. This brick-red layer has a blocky look to it. // History Early history Native Americans have lived in Utah for several thousand years; most archeological evidence dates such habitation about 10,000 to 12,000 years ago. ...

The middle layer is the Slickrock member, named for the type locality at Slickrock, Colorado; Rounded beach sands were cemented together to create this uniform layer.

The Moab Tongue member is the uppermost deposit, named after the type locality of Moab, Utah. The whitish sands from inland dunes make up this "cap rock" layer, as seen atop Delicate Arch and Broken Arch in Arches National Park. Moab is a city located in Grand County, Utah. ... Delicate Arch - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Arches National Park is U.S. National Park located near Moab, Utah noted for its concentration of natural arches—about 2,000 have been located within the park. ...