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<br />MAY 1 Q82 <br /> <br />In most of the area underlain by the Mancos Formation, ground water <br /> <br />moves generally downward through permeable sandy alluvium or fractured shale <br /> <br />to a firm shale layer and then laterally discharging into the streaQ systeQ <br /> <br />along major drainageways. In areas underlain by the Dakota Formation and <br /> <br />older rocks, the ground water moves through the fractures in the sandstone <br /> <br />layers and mostly discharges into the major streams. A small part of the <br /> <br />ground water moves very slowly down the dip of the sandstone (mainly <br /> <br />southeastward) into the San Juan structural basin. <br /> <br />Soils <br /> <br />Soils in the Montezuma Valley follow the pattern of geologic materials <br /> <br />shown in Figure 111-2. <br /> <br />Soils in the southern part of the valley originated predominantly from <br /> <br />marine shales and sandstone, giving their gray color, medium to fine (silty) <br /> <br />textures with good water intake rates and moderately high salt content. The <br /> <br />soils of the higher alluvial fans are generally shallow (3 to 4 feet) above <br /> <br />cobble, while the flood plain soils generally extend to depths of 20 feet. <br /> <br />In the northern part of the valley the windblown soil deposits are loam to <br /> <br />light clay loam in texture, with good water intake rates and no salinity or <br /> <br />alkalinity problems. These soils range from deep, well drained deposits to <br /> <br />shallow soils over sandstones at 10-20 inch depth. The irrigated area is <br /> <br />characterized by rolling topography with slopes of up to 12 percent. Less <br /> <br />than 10 percent of the area has slopes under 2 percent. Land in the <br /> <br />Montezuma Valley has been irrigated for over 70 years. <br /> <br />History and Archaeology <br /> <br />The Dominguez-Escalante Trail of 1776, designated for study under the <br /> <br />provisions of the National Trail System Act of 1976 (Public Law 94-527) to <br /> <br />determine eligibility for inclusion in the system, passes through the area. <br /> <br />The trail marks an historic I,BOO-mile trip by two Franciscan padres, Fray <br /> <br />111-4 <br /> <br />r.'"18 <br />" <) /1 0 <br />