Figure 8 shows that the unnamed upper member of the Hermosa Formation and the overlying Cutler and Moenkopi Formations are thickest beneath the Courthouse syncline but wedge out against the flanks of the anticline. Although the Chinle Formation and younger rocks appear to extend across the fold, and may have extended across this part of the fold, in Colorado all rocks older than the Jurassic Morrison wedge out against the flanks of the salt anticlines (Cater, 1970, p. 35) and also in the widest part of the Salt Valley anticline southwest of the section in figure 8. The salt anticlines were uplifted in a series of pulses so that some formations either were not deposited over the rising structures or were removed by erosion before deposition of the next younger unit. By Morrison time the supply of salt beneath the synclines seems to have become used up; hence, the anticline stopped rising, and the Morrison and younger formations were deposited across the structures. Thus, in figure 4, the minimum thickness of all units older than the Morrison is given as zero. Figure 4 shows the marine Mancos Shale to be the youngest rock unit exposed in the park, but the Mesaverde Group of Late Cretaceous age and possibly the early Tertiary (fig. 59) Wasatch Formation may have been deposited and later removed by erosion. Uplift And Erosion of The Plateau Next among the main events leading to the formation of landforms in the park was the raising and additional buckling and breaking of the Plateau by Earth forces partly during the Late Cretaceous but mainly during the early Tertiary. After uplift and deformation, the Plateau was vigorously attacked by various forces of erosion, and the rock materials pried loose or dissolved were eventually carted away to the Gulf of California by the ancestral Colorado River. Some idea of the enormous volume of rock thus removed is apparent when one looks down some 2,000 feet to the river from any of the high overlooks farther south, such as Dead Horse Point (Lohman, 1974, fig. 15). Not so apparent, however, is the fact that younger Mesozoic and Tertiary rocks more than 1 mile thick once overlaid this high plateau but have been swept away by erosion. In all, the river has carried thousands of cubic miles of sediment to the sea and is still actively at work on this gigantic earth-moving project. In an earlier report (Lohman, 1965, p. 42) I estimated that the rate of removal may have been as great as about 3 cubic miles each century. For a few years the bulk of the sediment was dumped into Lake Mead, but now Lake Powell is getting much of it. When these and other reservoirs ultimately become filled with sediment—for reservoirs and lakes are but temporary things—the Gulf of California will again become the burial ground.