Paleontology and stratigraphy of the upper cretaceous rocks between Mount Taylor and the Rio Puerco, New Mexico

The area covered in this report lies between Mt. Taylor and the Rio Puerco, and embraces approximately 675 square miles. Much of it is readily accessible by either paved highways or improved roads. The general region is a land of numerous mesas, the largest of which is Mesa Chivato. Sandstones form prominent ridges while shales and alluvium form the valleys. Many volcanic plugs stand out as landmarks