OCR Text |
Show APPENDIX G 281 in the coarse sandstones of the Morrison (Jurassic) formation which underlies the shales and sandstones of the Cretaceous and is underlain by other strata of the Jurassic. The canyon section is characterized by a notable combi- nation of geological, scenic, archeological, and biological values and by its wilderness quality. Its most spectacular features are the canyons of the Green and Yampa Rivers, where interesting geological formations and impressive landscapes are displayed in great variety. One of the exceptional attributes of this section consists of contrasts of these two canyons in their geological formation and scenic character. Echo Park, at the confluence of the Green and Yampa Rivers, is especially notable because of the high, knife-ridge of sandstone known as Steamboat Rock, which rises vertically about 750 feet above the junction of the Green and Yampa Rivers. In addition to the predominant geologic and wilderness values of the canyon section, there are noteworthy archeolo- gical features. Evidences of prehistoric Indian life have been found in many areas and include campsites, rock shelters, petroglyphs, burials, and caves that were inhabited or used for storage. The archeology of the region is not yet fully known nor have all sites been adequately investigated and recorded. Likewise, the many interesting historical aspects of the area have not been adequately chronicled. In addition, there are distinct biological interests. Deer are abundant in some sections, and there have been reports of mountain sheep. There are also many plant associations which are correlated with geological structure and interesting biotic units whose origins are related to the development of the can- yons and the local mountain structures on the flank of the Uinta Mountains. Forms of animal and plant life reveal influences of the hardy climate and are evidences that much of interest might be revealed by a careful biologic survey. In connection with investigations of the Colorado River Basin under authority of the federal reclamation laws and acts amendatory thereof or supplementary thereto, particularly the Boulder Canyon Project Adjustment Act of July 19, 1940 (54 Stat. 744), the Bureau of Reclamation has studied for several |