[Illustration: EVAPORATION PONDS, used to separate potash from common salt, viewed from jeep trail. Black borders are parts of plastic membranes covering bottoms of ponds. Crest of Cane Creek anticline and La Sal Mountains in right background. (Fig. 71)] Across the river east from Potash is Jackson Hole, a large rincon. Since abandonment, which shortened the river by about 3½ miles, the river has cut its channel nearly 200 feet deeper. It is comparable in size to the large rincon along Green River below Bowknot Bend (p. 90) but probably is somewhat younger. Both rincons may be as old as late Tertiary (fig. 80). Just below Potash we cross the axis of the huge Cane Creek anticline (fig. 31) and also leave Grand County to enter San Juan County. A mile east of this point, high on the canyon wall, is the School Section 13 uranium mine, which has yielded considerable ore and is expected to resume production sometime during 1973. It can be seen from the river or the trail, and some of the tailings are visible on the left flank of the anticline in figure 13. Voyagers who cross the axis of the Cane Creek anticline may observe on the right-hand (west) bank a protruding oil-well casing, some drill bits, and several shacks—all that remain of the Frank Shafer No. 1 oil test started during the winter of 1924-25 and completed by the Midwest Exploration Co. (Baker, 1933, p. 81). As described by Maxine Newell (U.S. Natl. Park Service, written commun., 1970), The well blew in in December 1925, caught fire, and spewed burning oil 300 feet into the air. * * * The local Times-Independent newspaper called it “Mother Nature’s Christmas Gift to Grand County.” The gusher burned down the rig, a barge of equipment, and it took three months to get it under control. Then it didn’t produce. Various 1925 and 1926 issues of the Moab Times-Independent reported that despite many efforts to plug the well, it continued to flow from 1,000 to several thousand barrels of oil per day for 6 months or more, all of which floated down the river. The last blowout occurred in 1937, after which the well was plugged with an additional 180 tons of cement. Mrs. Newell added, The stories told of the early-day exploration are endless and delightful. Equipment and supplies were barged down the Colorado River by the old Moab Garage Company; in winter months materials were carried by team and sled over the river ice. They would take a couple of rig timbers and pile a lot of lumber on them (they could take 10,000 feet), then we’d give them a start with a crowbar and the mules would trot all the way downhill to the well. When they’d get there they had a little trouble stopping sometimes; they would turn into the bank, unload, then put the double trees on one mule, ride the other, and head back for a new load of rig lumber.