In 1962, WSU archeologists Richard Daugherty and Roald Fryxell began excavating the Marmes Rockshelter, near where the Snake and Palouse rivers meet. During the excavation, they found what was then the oldest human remains in the western hemisphere at approximately 12,000 years old.

The site was scheduled to be flooded during the construction of the Lower Monumental Dam, but thanks to the discovery President Lyndon Johnson authorized the construction of a coffer dam to protect it. Unfortunately, in 1969, the site was flooded anyway because of leaks under the dam. It had only been partially excavated.