If you're new to rock art and petroglyphs, you'll undoubtedly run across a few terms that you're unfamiliar with. Several of these terms will be used here too. To refresh those who are already aquainted with rock art terminology and, to enlighten others who are not familiar with them. Here are some of the basics:
Petroglyph - greek: petro meaning rock, and glyph meaning drawing or engraving.
Anthropomorphism - the attributing of human shape or characteristics to gods, objects, animals, etc.
Pecking - (or small peck) used to describe a method used to create a petroglyph. Whereby a tool, such as a sharp pointed rock, was utilized in a percussive manner, to hit the rock and carve the drawing. The tool may have been used alone or with a "hammerstone" to peck the bearing surface. Petroglyphs made in this manner have a rough, pitted surface. All petroglyphs observed at the site locations here appear to be made by the small peck method.
Pictographs - ancient rock art symbols that are drawn or painted onto rock, normally without any pecking or abrasive methods of creating the scenes or symbols. Paint made from powdered minerals, blood, charcoal, or other substances were used to make pictographs.
Rock varnish - a substance which forms over time onto the surface of rocks causing darkening of the color of the rock. Microscopic organisms residing on the rocks surface secrete a substance that causes airborne specks of certain minerals to stick to the rock. Over long periods of time, as the varnish accumulates over petroglyphs too, the petroglyph can become as dark as the rock. Sometimes leaving it very hard to see in contrast to the surrounding natural coloration of the rock.
Dennis Slifer; Signs of life - Rock art of the Upper Rio Grande; Ancient City Press 1998. IBSN 1-58096-005-7
Elizabeth C. Welsh; Easy Field Guide to Southwestern Petroglyphs; Primer Publishers Sixth Printing - 1998. IBSN 0-935810-60-9