In the area east of the small community of Bagdad and on the northeast edge of the Arrastra Mountain Wilderness of central Arizona in the USA, my friends, Terril, Yvette and David, stood with me at the base of a vision in the desert of a rockhound’s dream. This was a colourful, irregularly shaped hill, standing alone in the arid wildlands, its bright whites, reds and greens standing out against a blue and white March sky. The entire hill seemed composed entirely of loose stones of quartz, caliche (a mineral deposit of gravel, sand and nitrates found in dry areas of the USA), basalt, travertine, green quartzite, tuff and gabbro. One whole side of the hill was white from quartz. We had attempted to climb this amazing thing. But, like wonderful things in a dream, most of it eluded us. We could climb but a metre or so, before we slid back down, unable to secure a foothold. However, the four of us collected about a bucket full of the rocks on this Bureau of Land Management land.
Just across the roadway to the south, we had hiked a short distance across an arroyo (a Spanish word for a dry creek or stream bed). Here, the rocks visible at the surface were quite different and we saw less travertine and more quartzite. No titanic mounds of loose stones met our seeking eyes. What we did see were large basalt boulders, some reddish scoria and gabbro, and some sand, as well as desert pavement along the Santa Maria River. How could the geology appear so different on either flank of a relatively narrow highway?
David Hawk and I had only been in Arizona for one day and we could already see that the geology of the state was very complex. Our ride on a commuter shuttle from the big city of Phoenix, north along Interstate 17 to Prescott, treated us to views of dark rocks and many mines. Upon arrival in Prescott to stay for a short while with Terril and Eve, we had a chance to see the varied geography, and also the animal and plant life of this region. Many habitats intersect here. In Prescott, there are forests of ponderosa, juniper and pinon pine, as well as acreages of short grass prairie upon which graze small herds of pronghorn, a unique species of ungulate related to sheep but closely resembling antelope. David and I had never seen these animals before. Eve and Terry knew this area well, and both are in the environmental education field and tireless advocates for the Arizona ecosystem, so we knew we had great guides in our quest for the ‘real’ Arizona, that is, the part of the state seldom seen by tourists.