Devil's Postpile National Monument,
Reached from Mommoth Lakes Calif., this national monument is a fascinathing basaltic lava flow formation. This flow occurred about 915,000 years ago and was succeeded glacial advances which removed on side of the Postpile. The remaning 4, 5 and 6 sided colums are from 30 to 50 feet long high. On the top of the postpile may be seen a Natural Mosaic created by erosion of the passing glacial ice.