Figure 20. Photograph of an in-situ fossilized tree base and root system in the roof of an underground coal mine. The coal bed being mined is in the Cretaceous Blackhawk Formation, Wasatch Plateau coal field near Huntington, Utah. Note the radiating root network. Photograph by Alex Papp (ARCO Coal Company, Denver, Colo.) in Atlas of Coal Geology, American Association of Petroleum Geologists (AAPG) Studies in Geology No. 45 (Papp and others, 1998); AAPG copyright 1998, reprinted by permission of the AAPG, whose permission is required for further use.