Erosion is still going on slowly and persistently among the great pillared cliffs of the monument. Some of the most exposed portions have already been worn away. Pedestal or balanced rocks have formed and fallen; others are tottering; more are just taking shape. Within the span of a human life, only minor changes may be noticed, but with the passage of the centuries the face of Nature is ever changing. Although the spectacular erosional remnants and the massive columnar structure of the cliffs will impress you even if you hurry through, you will see much more of geological interest if you can stop and use the trail. Here and there are exposed beds of volcanic ash and cinders, indicating the explosive nature of some of the ancient eruptions. Road construction has uncovered shale which was once the mud of a lake bed. One trail is strewn with “volcanic hailstones” weathered out of a ledge composed of millions of marblelike pellets firmly cemented together into a peculiar “peanut-brittle” rock. Plant and Animal Life Because of its location as a mountainous island in a sea of arid grassland, the Chiricahua Range affords a haven for a multitude of plants and animals of many varieties. Winter snows and summer rains result in springs and small streams. Dense vegetation covers the shaded canyon bottoms and the cool north slopes of the higher elevations. In contrast, south exposures feel the full heat of the summer sun and have plants characteristic of the desert. Red-stemmed manzanitas and bark-shedding madrones rub branches with the chalky-white limbs of the sycamore and the feathery gray foliage of the Arizona cypress. Green slopes, covered by chaparral of scrub oak and manzanita, face open hillsides dotted with a desert vegetation of yuccas, century plants, and cactuses. Seasonal changes bring with them many varieties of wildflowers. Arizona whitetail deer are numerous in the Chiricahuas, and in the monument, where they are protected, they become accustomed to man and are frequently seen. Coatimundi and peccary are increasing in numbers. Rodents are common, as are birds of many species. Each vegetative belt and plant association has its own distinctive animal population, some of which are unique because of the relative and long-established isolation of the Chiricahua Range. Historical Background