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<br />' The mines are situated between Ward Creek and <br />' Cottonwood Creek (approximately two miles above their <br />confluence; see Map 1). While the great majority of alluvial <br />' material occurs as mudflow fans, four river terraces were <br />' identified to the south of the area which is covered by the <br />alluvial mudflow fans (see qaf on Map 7 - Geomorphology). <br />The oldest and uppermost of these terraces is exemplified by <br />Bluenose Mesa. This terrace, designated as Qt4 on Map 7, is <br />approximately 200 feet above the current stream channel of <br />' Ward Creek .and was formed by deposition of a mudflow on a <br />pediment surface (possibly with later reworking of the <br />' mudflow surface into a terrace landform). Alluvium on the <br />Qt4 terrace consists generally of extremely large basalt <br />boulders in a matrix of reddish-brown silty sediment. The <br />resulting reddish brown soil was the original "mud" which <br />carried the boulders. The depth of alluvium on this terrace <br />is 10 to 20 feet. The boulders are unsorted. The rationale <br />for identifying this feature as a terrace (rather than as a <br />' fan) is that its surface is shaped like a level terrace <br />rather than a convex fan and that this landform follows the <br />' stream in a linear fashion similar to a terrace. The <br />alluvial material of the Qt4 terrace overlies the clayey <br />Mancos Shale and is thus separate from the present day <br />alluvial aquifer. (This terrace is flood irrigated.) <br /> <br /> <br />' 77 <br />