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plea, most likely associated with the original down cutting of <br />• the valley by the Ancient North Fork of the Gunnison River. This <br />ancient slope failure complex apparently begins immediately east <br />of the present cemetery location and extends west approximately 1 <br />mile down the valley. Based upon our field observations and <br />study of area topographic mapping, this ancient slope failure <br />complex appears to be approximately bounded by Elk Creek to the <br />east, Bear Creek to the west and the Rollins sandstone outcrop <br />near the valley bottom (southern limit) and the upper slopes at <br />elevations ranging from approximately 6600 feet to the east, <br />rapidly rising to 7000-7200 feet to the north and northwest <br />margins. Four major ancient and very eroded .slope failure com- <br />plex features are tentatively identified. The site of this <br />proposed coal mine waste bank appears to be within the two east- <br />ern most features. <br />Based upon our interpretations of this <br />site geomorphology and geology, the tentatively identified slope <br />failure features are not believed to be the result of a single <br />event but, a long series of progressive events, gradually in- <br />creasing in size as the valley bottom was lowered by erosion of <br />the North Fork of the Gunnison River. It is our interpretation <br />that when the Rollins sandstone was reached and eventually <br />breached by the erosion of the North Fork of the Gunnison River, <br />the upper slope failures were not significantly aggravated by <br />increasing valley depth. It is believed that during the downward <br />erosion process, the North Fork and the unnamed drainages in this <br />area removed much of the slope failure material, deposited some <br />• coarse grained alluvial gravels and cobbles and set the stage for <br />4 <br />