Red Rock Wash

Upper photo is ca. 1925, from the Chester R. Longwell collection (#311-0174(2)) at the University of Nevada, Las Vegas. I took the lower photo on 15 April 2011. Photos are looking pretty much due north.
Longwell was the "grand old man" of southern Nevada geology. He started mapping on horseback in 1919, and his last published paper was in 1974. He recognized and defined most of the large-scale features of the geology around Las Vegas and in Clark County that we now take for granted.
The road I'm on (which evidently didn't exist when Longwell took his photo) is a barely passable Jeep track, still open to motorized traffic, that goes through Willow Spring gap in the Red Rock escarpment along Red Rock Wash, and then south behind the escarpment up a steep canyon. It eventually exits into Lovell Canyon road and the Pahrump highway. However, structures like stonework around culverts indicate this road was once in much better shape, and it may have been a CCC (Civilian Conservation Corps) project from the 1930s.
The upper part of Red Rock Wash follows the swale in the upper center of the photos. It marks the trace of the Keystone Thrust, which Longwell named, where gray Paleozoic limestones have been shoved over the light-colored sandstone to the east. The thrust also continues to the south, parallel to and near the road I'm on.
There are not many changes visible in almost 100 years. The road is the only obvious change. Other than that, the vegetation seems sparser in the 1920s. In particular, there's now a heavy growth of piñon-juniper in upper Red Rock Wash.