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
Hole in the Rock (rock formation) Hole in the Rock (rock formation) Hole in the Rock is a narrow and steep crevice in the western rim of Glen Canyon, in southern Utah in the western United States. Together with another canyon on the eastern side of the Colorado River, it provided a route through what would otherwise be a large area of impassable terrain. In the fall of 1879, the Mormon San Juan Expedition was seeking a route from south-central Utah to their proposed colony in the far southeastern corner of the state. Rejecting two longer routes, they chose a more direct path that initially took