the Altatl Rock petroghyphs are dominated by the entoptic patterns common during the initial stage of a vision. A smaller number of other petroglyphs, including bighorn sheep, human figures, footprints, and a horned lizard (the “horned toad”), are also present. Particularly notable at the site and the reason for its name is a realistically engraved throwing board or atlatl. Indeed, this is one of the best prehistoric renderings of an atlatl in North America; more typically, atlatl petroghyphs appear to have been schematized as a small circle bisected by a long line. As has been noted previously, atlatls were used as hunting implements to launch small dart-like spears prior to the appearance of the bow and arrow, which occurred at approximately AD 500. Although the complete replacement of the atlatl by the bow and arrow may have taken a few centuries to effect, as a general rule of thumb we can consider atlas motifs to be greater than 1,500 years in age. We can infer, then, that at least some of the petroglyphs at Atlatl Rock are 1,500 years old or more, although it is also likely that some of the engravings at this site were made both earlier and more recently.