Several years ago, while studying the geology of the Albuquerque quadrangle, New Mexico, I had a distant view of that geological wonderland made classic by Major Dutton in his report, on the Mount Taylor region. Since that time I have been anxious to visit the district, more especially to get a closer view of the remarkable volcanic buttes in the valley of the Rio Puerco, which Major Dutton interpreted as remnants of necks formerly connecting with overlying volcanoes which have long since been worn away.
The buttes are most abundant in an open valley excavated by the Puerco river through the eastern part of the great lava sheets surrounding the Mount Taylor volcanic mass, the valley being open to the north and south, inclosed on the west by the ragged escarpment of the larger Mount Taylor mesa and on the east by the smaller Prieta mesa. The mesa surface . . .