POTD September 23, 2013: Goblin Valley State Park, Emery County, Utah

Goblin Valley State Park, Emery County, Utah
Photographer: Keith Beisner

At Goblin Valley State Park on the southeast side of the San Rafael Swell, morning sun gives Wild Horse Butte an ethereal glow. The butte exposes all four geologic units present in the park: the Entrada Sandstone and Curtis, Summerville, and Morrison Formations. These strata record profound changes in Utah’s geography during Middle and Late Jurassic time, including the existence of coastal sand dunes, inundation by a shallow inland sea, and then uplift, erosion, and sediment deposition in stream channels and flood plains.