Cone-shaped rock formations, some rising 30 meters, are called hoodoos and are part of the Kasha-Katuwe Tent Rocks National Monument in northern New Mexico. They are the products of volcanic eruptions that occurred 6 to 7 million years ago that left pumice, ash, and tuff deposits over 300 meters thick which were later sculpted by the erosive effects of wind and water. Hoodoos are columns that typically consist of relatively soft rock capped by harder less easily eroded stone that protects the spire beneath it.