[Illustration: GLADE PARK FAULT VIEWED FROM THE AIR, crossing head of No Thoroughfare Canyon from left to right. Land south of the fault was dropped some 50 feet below that on the north side. Primitive road around head of canyon has been improved and realined since photographs were taken. The stereoscopic pair of aerial photographs may be viewed without optical aids by those accustomed to this procedure or by use of a simple double lens stereoscope, such as the folding ones used by the armed forces during and after World War II. Compare with the geologic map, figure 8. Photographs taken in 1937 by U.S. Soil Conservation Service. (Fig. 59)] [Illustration: LADDER CREEK MONOCLINE AND REDLANDS FAULT, looking northwest from lookout point near Little Park Road. Telephoto view of left half of this scene is shown in figure 29; photograph of Morrison Formation shown in figure 21 was taken from point about a mile farther north. (Fig. 60)] Résumé of Geologic History and Relation to Other National Parks and Monuments in the Colorado Plateau In the geologic story of the Monument discussed on pages 17 to 94, the geologic processes and events leading to the Monument of today were told in the order in which they occurred; therefore, the details of the geologic history have already been covered. Having finished this story and the trips through and around the Monument, let us see how the colorful canyons, cliffs, and other erosion forms fit into the bigger scheme of things—the geologic age and events of the Earth as a whole, as depicted in figure 61. As shown in figure 7, the rock strata still preserved in the Monument range in age from Proterozoic to Cretaceous, or from about 1,500 million to 100 million years old—a span of about 1,400 million years. This seems an incredibly long time, until one compares figures 7 and 61, and notes that the Earth is some 4,500 million years old, and that the rock pile in the Monument is only about a third the age of the Earth as a whole.