Rhyolite formations at Chiricahua National Monument NPS Photo. Show. By far the most noticeable natural features in the park are the rhyolite rock pinnacles for which the monument was created to protect. Rising sometimes hundreds of feet into the air, many of these pinnacles are balancing on a small base, seemingly ready to topple over at any time. The Civilian Conservation Corps (CCC), during their occupation here in the 1930s, named many of the rock formations that can be seen today.