A nearby tuff ring has a water-formed cave, called Fort Rock Cave, where in 1938 Luther Cressman from the University of Oregon discovered sagebrush sandals and human artifacts dated approximately 9,000 to 10,000 years ago. Hole-in-the-Ground and Big Hole are two nearby maars nearly one mile in diameter formed by steam explosion. They resemble impact craters formed by meteorites, but lack the heavy metal signature residues of space objects. Crack in the Ground