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<br />EXHIBIT D-3 <br />Page 6 <br />This unit is composed of two major ccmponenta. ]-bout 45 percent o! the <br />unit is rock outcrop, mainly sandstone, with score small outcrops o! ahala. <br />Another 49 percent of the unit has shallw soils, lees then 20 inches, <br />over underlying sandstone and some shale. These voila are stony and <br />usually have loamy, light-covered surface layers. The remaining 6 per- <br />cent of the unit is made up of soils with dark-colored surface layers and <br />mixed alluvial soils in the Dolores and San Miguel River bottoms. <br />Soil Mapping Unit 4: Moderately dark-colored deep soils of the meea• and <br />valleys <br /> <br />This mapping unit occupies several scattered areas from Gateway to <br />Norwood above the Dolores and San Miguel Rivers. Most of the other <br />delineations are along the south and west boundaries of the basin. This <br />unit is of moderate extent and encompasses about 10 percent of the bnein. <br />The landscape is characterized by large, nearly level to gently sloping, <br />upland valleys, and gently sloping mesas. Individual mesas are separated <br />by numerous drainageways that are entrenched to depths of 100 to 500 feet <br />and have steep sandstone walls. Tht dominant cover ie sagebrush with <br />some pinyon-juniper and rabbitbrush. Most the irrigated and dry crop- <br />land and potentially irrigable land of the basin is within this unit. <br />Most of the soils in this unit are formed in reddish-brown eolian <br />materials. Others are residual or alluvial from sandstone and shale. <br />About 45 percent of the unit is well-drained, deep and moderately deep, ' <br />with dark-colored surface layers. These soils are noncalcareous to <br />depths of 10 to 24 inches but have slight to moderate zones of lime <br />accumulation. They are moderately coarse to moderately fine textured <br />with subsoils that are usually finer textured than thn surface layers. <br />Another 40 percent of the unit is similar to the above except the aurfaca <br />layers are moderately dark-colored and have a lower organic matter con- <br />tent. Depth to calcareous material is 6 to 12 inches. Subsoil textures <br />range from moderately coarse to fine. Lime-cemented cobble and gravel <br />are common below the subsoil. About 10 percent of the unit is less than <br />20 inches deep over sandstone and shale. The remaining 5 percent consists <br />of alluvial soils in the drainageways. <br />Soil Mapping Unit 5: Dark-colored soils of the cold mountain slopes <br />There are several delineations of this unit in both Colorado and Utah. <br />It is one of the most extensive units, comprising about 22 percent of the <br />basin. Although precipitation is plentiful, the short growing season <br />limits crop production to mainly hay and pasture. <br />' ~ l .~_i. <br />. ;' <br />