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<br />II. Description of the Environment <br /> <br />A. Existing Environment of Dinosaur National Monument's Proposed <br />Wilderness Area <br /> <br />Physiollraphy <br /> <br />',I <br /> <br />Dinosaur National Monument is located in a remote, semi-arid <br />plateau region of Colorado and Utah. Its deep canyons, rivers <br />and high plateaus are superlative. (Exhibit D). <br /> <br />. <br /> <br />Rock formations of many ages are present in Dinosaur National <br />Monument (Exhibit E). Fossil remains of plants and animals <br />record a succession of ancient environments - marine, coastal <br />md desert. The gamut is run from simple llfe forms to the <br />Late Pre-cambrian through trilobites of the Cambrian Period <br />to mallBllallan vertebrates of the Tertiary, a time span "f some <br />1,700 million years, although not all geological periods are <br />represented between these extremes. <br /> <br />By far the most significant formation, both scientifically <br />and in public interest, is the Morrison. It is in the Morrison <br />Formation that the fossilized remains of dinosaurs and other <br />reptiles are found. In addition to the ridge where the present <br />quarry is worked, this sandstone formation crops out in the <br />Rainbow Park and Deerlodge Park areas. It is not inconceivable <br />to think that new reptilian remains may one day be found in <br />the monument. <br /> <br />The proposed wilderness consists of: (1) The bench and plateau <br />lands above the canyons, .(2) the steep rocky canyon s lnpes <br />and sheer rock walls. (3) a shore and bank habitat, comprising <br />the zone subject to flooding by the Green and Yampa Rivers <br />and the zone which is vegetatively dependent on the influence <br />of. subsurface river water, and (4) an aquatic habitat, contain- <br />,. ing a fauna distinctly indigneous to the Colorado River drain- <br />age including two endangered species of fish, the Colorado <br />squawfish (Ptychocheilus lucius) and the humpback chub (Gila <br />cvpha) (Exhibit F). <br /> <br />The canyon slopes and walls in the proposed wilderness have <br />been grazed very little by cattle and sheep since the livestock <br />industry was introduced a little more than a century ago. <br />Many kinds of native grass, forbs, shrubs and trees still <br />dominate the vegetative Bcene. Appendix C shows Table 5, <br />"Acreage of plant communities mapped in and around the presently <br />occupied bighorn sheep habitat in Dinosaur National Monument", <br />from a thesis by William Barmore. The pl'evalence of exotic <br />species such as cheat grass may be minor, but is locally <br />important in burned and disturbed areas. <br /> <br />12 <br />