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24 <br /> progressively decreases in the younger formations as they outcrop <br /> at greater distances from the mountain front . Between Lyons and <br /> the northern Colorado border a series of Northwest-tending high- <br /> angle bedrock faults offset the sedimentary beds. Draping of <br /> sediments over these faults produces a series of en-echelon folds <br /> and faults. Taken together, these intermediate-scale structure <br /> deformations, regional deformations produced by the Front Range <br /> and the Denver Basin, and more localized small-scale folding and <br /> faulting, result in a generally complex geologic setting <br /> throughout the Foothills Belt. <br /> A maximum of approximately 12, 100 feet of sediment is found in <br /> the vicinity of Dowe Flats. Only those formations beneath the <br /> lower Pierre Shale are present. In general, the geologic section <br /> is composed of alternating sandstone and shale layers and some <br /> limestones. Beginning at the bottom of the section and working <br /> upward in both depth and time, the individual units display a <br /> variety of depositional origins. <br /> All of these sedimentary units are Upper Cretaceous in age. The <br /> synclinal structure of the central Dowe Flats basin is such that <br /> the youngest (Pierre Shale) formation is exposed over much of the <br /> eastern portion of the valley bottom with the older strata <br /> forming concentric horseshoe like rings as they outcrop around <br /> the valley perimeter on the east and west margins. <br /> Structurally the region surrounding Dowe Flats is extremely <br /> complex with both intense and sometimes superimposed folding as <br /> well as post-Cretaceous faulting. In this context, the <br /> simplicity of the central interior portion of Dowe Flats is <br /> almost anomalous. Interpretation of available information does <br /> not indicate the presence of major faulting, shearing, or <br /> significant folding in the interior portion of Dowe Flats. <br /> The important formations in this area are all upper Cretaceous in <br /> age and are limited to the middle of the regional stratigraphic <br /> column. They include the Dakota Group, the Ft. Benton Formation, <br /> the Niobrara Formation and the Pierre Shale. The general <br />