A favorite image from Davis Mountains Vistas, the opening in the volcanic cliffs is Sunny Glen, photographed three miles north of Alpine on Highway 118.
The cliffs are capped by the Decie Formation with the break in the cliffs being a thin tuff horizon between lavas of the Morrow and McIntyre formations.
The light-colored patches above the left steer are of tuffs interbedded in the underlying Cottonwood Springs Formation. The top of this formation is about 5,100 feet on the cliffs compared to about 3,686 feet in a water well drilled near the highway. The difference of 1,414 feet is due to a fault that runs along the base of the cliffs.
