Kelso Dunes

With the Providence Mountains beyond. Looking northeast--this is sunset lighting. The Providence Mountains are capped by sedimentary rock, including much limestone, and there's even a small limestone cavern there ("Mitchell Caverns"). At one point it was a California state park, but last I heard it--alas--was a casualty of budget cuts. The Providence Mountains stand high enough--~7K ft/2134 m--that they catch significantly more rainfall than the surrounding desert. This feeds an aquifer in the valley below, as well as supporting a scrub piñon/juniper forest in a so-called "sky island". Back in the days of steam engines, the aquifer provided plenty of water for the locomotives, which would refill at the tiny (and now almost abandoned) railroad town of Kelso, barely visible at extreme left (note). Mojave National Reserve, California.