Brazos Mountains to 55 million years ago during the Laramide orogeny. To the east and northeast lie the Sangre de Cristo Mountains which share a similar geological history. The Brazos Cliffs, which form a dramatic backdrop to Tierra Amarilla, are formed of Precambrian quartzite. Brazos Mountains The Brazos Mountains is a range in far northern Rio Arriba County, in northern New Mexico in the southwestern United States. A high crest runs from the border with Colorado for over in a south-southeasterly direction. The high point of the range at is on Grouse Mesa, at the Brazos Benchmark. Two miles (3 km) to
Devil's Backbone (rock formation) left an isolated bedrock ridge remaining between two valleys. Rose Island, an amusement park popular during the 1920s that was destroyed by the 1937 Flood, stood on this rugged peninsula, at the base of the ridge on a level area. Charlestown State Park hiking trails do not provide access to the Backbone, but a loop around the old Rose Island site passes below the ridge. There is another location by the same name near Fort Ritner, Indiana, east of Bedford. Devil's Backbone (rock formation) Devil's Backbone is a rock formation and peninsula formed by the flow of Fourteen Mile Creek