Clements, Edith S., _Flowers of Mountain and Plain_. H. W. Wilson Co., New York, 1926 (3d edition). More, Robert W., _Colorado Evergreens_. Denver Museum of Natural History, 1949. Guide to the conifers, with photographic illustrations. Nelson, Ruth Ashton, _Plants of Rocky Mountain National Park_. Government Printing Office, Washington, D.C., 1953. The basic reference on the wildflowers of the region. Pesman, M. Walter, _Meet the Natives_. Cooperative Printing Co., Denver, rev. ed., 1960. A guide to the flora of the region, with a color-key arrangement; useful anywhere in Colorado. Preston, Richard, _North American Trees_. Iowa State College Press, Ames, Iowa, 1948. An illustrated guide to all species of trees of North America. Roberts, Harold and Rhoda, _Common Wildflowers of Colorado_. Museum Pictorial No. 8, Denver Museum of Natural History, 1959. Roberts, Rhoda, and Ruth Nelson, _Mountain Wildflowers of Colorado_. Museum Pictorial No. 13, Denver Museum of Natural History, 1957. Fifty common mountain wildflowers described and illustrated. _Fishes_ Beckman, William C., _Guide to the Fishes of Colorado_. Leaflet No. 11, Univ. of Colorado Museum, Boulder, 1952. _Geology_ Pearl, Richard M., _Nature as a Sculptor_. Denver Museum of Natural History, 1956. A geological interpretation of western scenery, chiefly Colorado. Rocky Mountain Nature Association, _Glaciers of Rocky Mountain National Park_. Published in cooperation with National Park Service, U.S. Department of the Interior, 1959. Glacier story of Rocky Mountain National Park, past and present. U.S. Geological Survey, _Denver Mountain Area Map_. 1955. Covers most of Colorado’s Front Range and explains its geology. Wegemann, Carroll, _A Guide to the Geology of Rocky Mountain National Park_. Government Printing Office, Washington, D.C., 1955. Helpful road logs and the general geologic story of the park. _Mammals_ Burt, W. H., and R. P. Grossenheider, _Field Guide to the Mammals_. Houghton Mifflin Co., Boston, 1956. A manual for the identification of all mammals north of Mexico. Rodeck, Hugo G., _Guide to the Mammals of Colorado_. University of Colorado, Boulder. _Mountain Climbing and Hiking_