Coke Ovens is a prominent natural formation of four sandstone pillars on the west side of Monument Canyon in Colorado National Monument near Grand Junction. Its name comes from the rounded, beehive-like shapes that resemble nineteenth-century coke ovens once used to convert coal into fuel for iron smelting. The formation is a remnant of differential erosion, carved mainly from Wingate Sandstone deposited as wind-blown dunes about 200 million years ago in the Late Triassic. One pillar is capped by tougher Kayenta sandstone, while nearby slopes and the canyon floor expose older Chinle deposits and Precambrian gneiss, schist, and granite, revealing the canyon’s long geologic history.