Pearl, Richard M., 1969, EXPLORING ROCKS, MINERALS, [FOSSILS] IN COLORADO. Swallow Press, Revised Edition.
Pearl, Richard M., 1971, COLORADO GEM TRAILS AND MINERAL GUIDE. Swallow Press, 3rd Edition.
Powell, John Wesley, 1876, REPORT ON THE GEOLOGY OF THE EASTERN PORTION OF THE UINTA MOUNTAINS AND A REGION OF COUNTRY ADJACENT THERETO. U. S. Geological and Geographical Survey of the Territories. One of the earliest accounts of geology in Colorado, written by the explorer of the Colorado River and the father of the U. S. Geological Survey.
Rabbit, Mary C., and others, 1969, THE COLORADO RIVER AND JOHN WESLEY POWELL. U. S. Geological Survey Professional Paper 669. A resumé of part of Powell’s work and a good discussion of the geologic history of the entire Colorado River, which begins near Grand Lake.
Richmond, Gerald M., 1965, [GLACIATION] OF THE ROCKY MOUNTAINS. A part of THE QUATERNARY OF THE UNITED STATES, Princeton University Press. A summary of current knowledge of glaciation in Colorado and surrounding areas.
Rodeck, Hugo G., editor, 1964, NATURAL HISTORY OF THE BOULDER AREA. University of Colorado Museum Leaflet No. 13. Contains articles on geology and biology.
Untermann, G. E., and Untermann, B. R., 1954, GEOLOGY OF DINOSAUR NATIONAL MONUMENT AND VICINITY, UTAH—COLORADO. Utah Geological and Mineralogical Survey Bulletin 42. A detailed study of the eastern Uinta Mountains.
Weimer, Robert J., and Haun, John D., editors, 1960, GUIDE TO THE GEOLOGY OF COLORADO. Geological Society of America, Rocky Mountain Association of Geologists, and Colorado Scientific Society, Denver. A concise summary of many aspects of Colorado geology, this guide includes several geological itineraries and many reference listings.
Wolle, Muriel Sibell, 1949, STAMPEDE TO TIMBERLINE, Sage Books. An excellent account of early mining activity in the state, with many fine drawings of the early settlements.