Petrified Forest National Park Feature

Like some other historic sites in eastern Arizona, Petrified Forest National Park is a great place to view petroglyphs and pictographs—designs pecked or scratched into the stone are called petroglyphs; those that are painted on the surface are pictographs. Few pictographs remain because of the deleterious effects of weathering, but the more durable petroglyphs number in the thousands.

Where to Find It

The rock art of early American Indians is carved or painted on basalt boulders, on canyon walls, and on the underside of overhangs throughout the area. No one knows the exact meaning of these signs, and interpretations vary; they have been seen as elements in shamanistic or hunting rituals, as clan signs, maps, or even indications of visits by extraterrestrials.

Damaged by vandalism, many rock-art sites are not open to the public. Two good petroglyphs to check out are Newspaper Rock, an overlook near mile marker 12, and the Puerco Pueblo Trail near mile marker 11. Other sites in Arizona include Hieroglyphic Point in Salt River Canyon, Five-Mile Canyon in Snowflake, and Lyman Lake State Park.

Determining Its Age

It's just as difficult to date a "glyph" as it is to understand it. Archaeologists try to determine a general time frame by judging the style, the date of the ruins and pottery in the vicinity, the amount of patination (formation of minerals) on the design, or the superimposition of newer images on top of older ones. Most of eastern Arizona's rock art is estimated to be at least 1,000 years old, and many of the glyphs were created even earlier.

Variety of Images

Some glyphs depict animals like bighorn sheep, deer, bear, and mountain lions; others are geometric patterns. The most unusual are the anthropomorphs, strange humanlike figures with elaborate headdresses. Concentric circles are a common design. A few of these circles served as solstice signs, indicating the summer and winter solstice and other important dates. At a certain time in the year, when the angle of the sun is just right, a shaft of light shines through a crack in a nearby rock, illuminating the center of the circle. Archaeologists believe that these solar calendars helped determine the time for ceremonies and planting.

Many solstice signs are in remote regions, but you can visit the Petrified Forest National Park around June 20 to see a concentric circle illuminated during the summer solstice. The glyph, reached by paved trail just a few hundred yards from the parking area, is visible year-round, but a finger of light shines directly in the center during the week of the solstice. The phenomenon occurs at 9 am, a reasonable hour for looking at the calendar.

Do not touch petroglyphs or pictographs—the oils from your hands can cause damage to the image.