About 5 miles below the mouth of Rustler Canyon and Indian Creek, and also about 5 miles above the confluence, is The Loop—an even sharper and more symmetrical figure eight than Bowknot Bend of the Green River (fig. 62). An aerial view of The Loop (fig. 74) shows that the channels on the south loop are only about 500 feet apart and that those on the north loop are only about 1,700 feet apart. At the narrowest places, both saddles are considerably eroded—the southern one is only about 150 feet above the river, but the northern one is still about 350 feet above. Erosion of both saddles has been hastened by the facts that the axis of the Meander anticline (see p. 108) passes through each saddle and that an interesting reverse fault (fig. 75) passes through the lower and thinner southern saddle. The differences between reverse and normal faults are shown by comparing figures 56 and 76. It seems inevitable that some day the small saddle will be cut through by the Colorado River, and a new rincon will result. Eventually, the other loop also probably will be abandoned. As one of my colleagues remarked, how wonderful it would seem, to be present at the proper moment to witness such an event, particularly if one had a time-lapse movie camera to record it for posterity! [Illustration: REVERSE FAULT in southern saddle of The Loop, looking northwest from boat in river. Apparent angle of dip is 12° below horizontal. Rocks at left, above fault plane, have been shoved about 10 feet past and over those on right. Curving of dark bed near middle of fault plane is called “drag.” (See fig. 76.) Rocks are unnamed upper member of Hermosa Formation. (Fig. 75)] [Illustration: CUTAWAY VIEW OF REVERSE FAULT, resulting from horizontal compression, which caused a shortening of earth’s crust. Note “drag” of beds on each side of fault plane. Low-angle reverse faults, also called thrust faults, may have displacements ranging from a few feet to many miles. From Hansen (1969, p. 116). (Fig. 76)] About a mile and a half below the south saddle of The Loop we meet the mouth of Salt Creek, which drains a large part of the Needles district. Figure 77 was taken in Salt Creek canyon about 2 airline miles above the mouth looking southeast toward Six-Shooter Peaks and Shay Mountain, northernmost of the Abajo Mountains, on the horizon.