When you look at Google Maps, Agathla Peak first appears as El Capitan. El Capitan is the Spanish name, Agathla Peak the anglicized version of the Navajo name.
According to the fine folks at Wikipedia, this means ‘much wool'. This is a reference to the fur of antelope and deer caught on the rocks. To the Navajo, the peak, thrusting some 1500 feet above the surrounding plain, is a sacred place. That doesn't seem to stop lots of people from climbing it for the view.
The peak is an eroded volcanic plug consisting of, ‘volcanic breccia cut by dikes of Minette'. Minette is one of many lamprophyres – igneous rocks with unique mineralogy that don't lend themselves to simple classification. Some of those words bring back memories of my geology studies at Exeter some 37 years ago. Of course, I still have many of my textbooks from those classes. While there are no photographs of Minette in my minerals textbook, there are images of several other lamprophyres.
I recently re-discovered this image that I took in the fall of 1995. Initially, I thought it was a photo of Shiprock in New Mexico, but that the geometry of the image didn't feel right. Continuing my research and looking at the photos I took before and after, I realized this one was on the road to Monument Valley.
Take Arizona Highway 163 north out of Kayenta and Agathla Peak starts appearing on the horizon while you're still five or six miles away.
