The Chiricahua Mountains rise above the surrounding grasslands, providing shady forests and glens that harbor Mexican chickadees, raccoon like coatimundis, javelina and a number of other wildlife species. Among the monument's outstanding features are gigantic, erosion-sculptured monoliths of volcanic rock. Current research indicates that about 27 million years ago violent eruptions from the nearly Turkey Creek caldera took place, covering the area with white-hot ash. After the ash fused and cooled into an almost 2,000-foot layer of rock, the forces of erosion sculped it into the odd array of shapes that can be seen. Formations include the Totem Pole, 137 feet high and only a yard thick at its narrowest point; the Mushroom; and Big Balanced Rock, weighing 1,000 tons and resting on a base about 4 feet thick. In some places canyon walls rise as much as 1,000 feet. Many areas can be reached only by foot. Picnicking, camping and parking areas are available.