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. .._ - - -^ -- ~ -- - - - - - 'L -- .. ~. 2.06.8 (3) Alluvial Valley Floor Detennlnation Examination of the Permit Area for evidence of atlwlai valley floors was conducted on October 19-22, 1981 by Western Engineers, inc. Geologic Setting The Wet Maintains border the permit area on the south. Tha permit and wrrounding areas lie on rortheasterly slopes which form the transition between the Great Plains province and the front edge of the Rocky .Mountains. The permit area is underlain by Tertlery and Cretaceous age rocks which have been drag folded by the West Mountain thrust which came from the southwest. The axis of the resulting • Chandler Syncline traverses the south and west portions of the permit area in an arc and plunges from the southeast corner toward the northwest corner. Pediment deposits eroslanally dissected by modern streams cap the slopes of the penult and surrounding areas. Geanorphotogy/Topography of Surface Oralnage The pediment surface fornis a series of long nearly flat-topped mesas which scope northeasterly. Several stream flaw generally northeast across this old wrface and most have eroded valleys through the gravelly, bouldery pediment deposits. All but one of the streams crossing the area are shown as intermittent on the U.S.G.S. 7 1/2 minute topographic maD of the Rockvale Quadrangle, Colorado. Newlin Creek Is shown to be a peremlal stream and Is the longest stream crossing the area. Newlin Creek Is dry most of the year on the permit area and below due to diversion of water above the permit boundary by the City of Florence. . Most of the streams of the area around and within the permit Boundary are tributary to Newlin Creek. Two I ntennlttent streams, not tributary to Newlin Creek lie In the extreme northwest confer of the permit area. The first Is a tributary of Coal Creek which begiru 1 1/2 miles above the permit boundary an outcrops of Precambrian biotite