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sedimentary and igneous rocks underlie the watershed. The Elk and West Elk <br />• Mountain ranges were formed by Paleozoic strata thrust upon one another <br />with laccolithic intrusions (Johnson 1948, USDI 1978). The igneous intru- <br />sions are predominantly quartz monzonite of Tertiary age. <br />The remainder of the watershed is underlain by sedimentary strata in <br />the following sequence: <br />Wasatch Formation - Tertiary Age <br />Ohio Creek Conglomerate - Tertiary Age <br />Mesaverde Formation - Cretaceous Age <br />Barren Member <br />Paonia Member <br />Bowie Member <br />Rollins Sandstone Member <br />Mancos Shale Formation - Cretaceous Age <br />• The Bowie and Paonia Members of the Mesaverde Formation contain <br />mineable coal seams. The Hawk's Nest Mine is mining the E coal seam within <br />the Paonia member. <br />Drainages have moderately dissected the formations creating landforms <br />associated with narrow V-shaped valleys. The igneous areas have not been <br />extensively dissected due to their position in the upper portions of the . <br />watershed and their resistance to erosion. Thick resistant sandstones form <br />vertical to steep cliffs and escarpments. Shales and other less resistant <br />beds form gentle slopes between the cliffs and ledges. In profile, this <br />creates a stairstep appearance. Because of the predominance of sandstones <br />in the Mesaverde Formation, escarpments, sharp ridges, and narrowly cut <br />canyons are the major landforms of the area. <br />r~ <br />2.04-9 <br />