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) Devil's Backbone (rock formation) Devil's Backbone is a rock formation and peninsula formed by the flow of Fourteen Mile Creek into the Ohio River, and is currently situated in Charlestown State Park near Charlestown, Indiana and across the Ohio River from Louisville, Kentucky. According to local legend, on this bedrock ridge once stood a stone fortress that was built by Welsh explorers led by Prince Madoc sometime in the 12th century. The Backbone is believed to have been formed by the processes of glaciation where a combination of ice sheet advances, meltwater flows and a diversion of the Ohio River