Trees were entombed in silica-rich volcanic mud. April 26, 2014 by Matt ThomasTrees were entombed in silica-rich volcanic mud. Florissant Fossil Beds National Monument About Matt Thomas Matt is an avid writer and explorer, who loves to showcase his home state of Colorado. His favorite place to be is right here in the Centennial State. Previous Post:Florissant Fossil Beds National Monument – Divide