POTD June 10, 2014: Mary Ellen Gulch, American Fork Canyon, Utah County, Utah

Mary Ellen Gulch, American Fork Canyon, Utah County, Utah
Photographer: Tyler Knudsen; © 2013

Quartzite of the 900 million-year-old Big Cottonwood Formation holds up the rugged headwall of Mary Ellen Gulch. Well-preserved ripple marks and mud cracks indicate the Big Cottonwood Formation was deposited in the tidal zone of a shallow sea.