The Chuckanut Mountains were formed by the folding of the Chuckanut Formation (which is predominantly made up of layers of 55-million-year-old sandstone, conglomerate, shale, and bituminous and sub-bituminous coal) and the later Huntingdon Formation (predominantly shale and sandstone) on top, as well as an exposed section of pre-Jurassic-age phyllite
Mount Baker Wilderness (wilderness.net) The United States Congress designated the Mount Baker Wilderness in 1984 and it now has a total of 119,966 acres.