1. Flora of the Montana formation Author/Creator: Knowlton, Frank Hall, 1860-1926, author Publication/Creation: Washington, D.C. : Department of the Interior, United States Geological Survey, 1900 Resource Type: Book Access & Availability: Loading
2. Fossil wood and lignite of the Potomac formation Author/Creator: Knowlton, Frank Hall, 1860-1926, author Publication/Creation: Washington, D.C. : Department of the Interior, United States Geological Survey, 1889 Resource Type: Book Access & Availability: Loading