Until very recent times, Indian people of the Columbia River did not bury their dead but wrapped bodies in robes or tule mats and placed them in canoes set in the woods, on rocky points, or in cedar vaults on islands like Memaloose, a name derived from the Chinook word memalust, meaning "to die." The Corps of Discovery under Meriwether Lewis and William Clark passed the island on 29 October 1805 in their quest to reach the Pacific Ocean and called it "Sepulcher Island," or burial island. On their return journey, the explorers visited the island on 15 April 1806, and Lewis noted "thirteen sepulchers on its rock which stands near the center of the river and has a surface of about 2 acres above high water mark."