A photo of The Columbia River

This view is from Mayer State Park near The Dalles, Oregon. The view is looking south across the Columbia River to massive outcrops of basalt flows exposed in stacked succession along the Washington side of the river downstream of the Dalles Dam. The rocks are part of the Grande Ronde Basalt Formation (Lower to Middle Miocene) of the greater Columbia River Basalt Group (Norman and Roloff, 2004; USGS, 2009).