Withrow Moraine and Jameson Lake Drumlin Field erosion resulting from the Missoula Floods, which laid bare many layers of the basalt flows on the edges of the plateau at Grand Coulee and Moses Coulee. Two million years ago the Pleistocene epoch began and Ice age glaciers invaded the area. They scoured the Columbia River Plateau, reaching as far south as the middle of the Waterville Plateau highlands above the Grand Coulee and south to the head of Moses Coulee. In some areas north of the Grand Coulee they were as much as 3 km (10000 feet) thick. Grooves in the exposed granite bedrock are still visible in
Lind Coulee Archaeological Site Lind Coulee Archaeological Site The Lind Coulee Archaeological Site, also known as 45GR97, is the site of an archaeological dig near Warden, Washington. It dates to c. 11,000 cal BP. When it was first discovered in 1947, the site was seen as the first evidence of human habitation of Washington older than about 2,000–4,000 years. It was discovered by the River Basin Surveys program of the Smithsonian Institution. Richard Daugherty (then a graduate student at the University of Washington) was informed of the existence of bones and stone tools about underground, and he began visiting the site in 1948. From