For the Yuman-speaking inhabitants of the Colorado River region, no location was more sacred than Avikwa'ame, or Spirit Mountain, which we call Newberry Peak, in southernmost Nevada. According to the Mojave creation myth, the oldest spirit was Matavilya, made from the mating of Earth and Sky. Matavilya had two sons, Mastamho and Kaatar, and a daughter, Frog. Matavilya committed an unwitting indecency that offended his daughter, who then killed them. Mastamho directed the cremation and mourning ceremony for his father and, when completed, strode up the Colorado River Valley. When he got to the top Mastamho created the river by plunging a cane of breath and spittle into the earth, allowing the river to pour forth. Riding a canoe down the waters to the ocean, he created the wide river bottom by twisting and turning the boat. He returned from the ocean with his people, the Mojave, taking them in his arms to the northern end of Mojave country. There he piled up earth, creating the mountain Avlkwa'ame, and built himself a house on it. There too Mastamho plotted the death of Sky- Rattlesnake, an evil spirit and the source of dark powers. Mastamho killed Sky-Rattlesnake by cutting off his head, with his spilt blood becoming noxious insects. Mastamho then gave land to the different tribes and taught them to farm. Finally, Mastamho turned himself into a fish-eagle and flew off into oblivion.

 The importance of this cosmogenic myth to rock art is two folds. Known as the "Shaman's Tale," it was precisely this myth that the shaman "dreamed" to obtain his supernatural powers: In Yuman fashion, the shaman was believed to re-experience and witness these mythic events of creation in the supernatural world and, from them, obtain his power. As the anthropologist Alfred Kroeber wrote in 1925, "It is of [Mastamho's] house that shamans dream, for here their shadows were as little boys in the face of Mastamho, and received from him their ordained powers, confirmed by tests on the spot." It is at the foot of Spirit Mountain that the important Grapevine Canyon petroglyph. Grapevine Canyon is Atastamho's House, where the Mojave shaman went to witness, in his dreams, the creation of the world.

  Grapevine Canyon is the biggest petroglyph site in southern Nevada. As at other Colorado River locales, representational or figurative motifs are rare at the site; they are heavily outnumbered by entoptic designs, many of which are deeply and widely engraved. The depth and width of these engravings reflect the fact that Yuman petroglyphs were studied and examined by initiates, and sometimes repecked by them. Still, considerable variation in the degree of revarnishing is evident at the site, indicating that Yuman shamans used this locale probably for many thousands of years. Recent accounts, on the other end of the time scale, tell us that it continued to be used into this century.

 Many of the entoptic engravings at the site are complex combinations of geometric forms; enclosed grid and netlike patterns and shield like motifs are particularly common. On some panels the dense overlay of engravings itself creates an almost uninterpretable, complex geometric motif, individual engravings can only be identified through careful examination of the dense palimpsest of Petroglyphs. There are some familiar motif types present at the site, however, such as occasional human figures (including a few "patterned-body anthropomorphs"), and even a few panels of bighorn sheep. Whether these represent Yuman Petroglyphs or instead were created by non-Yuman shamans is unknown. Avikwa'ame was widely renowned as a place of great supernatural power, so it is entirely possible that shamans from different cultures came here for their own types of vision quests.

  As implied above, the Petroglyphs at Grapevine Canyon apparently represent shamans' visionary images of Mastamho and the creation of the world. Clearly, though, these images do not comprise narrative depiction's of the different events in the creation myth, as I have noted in a similar vein concerning the Petroglyphs at McCoy Spring. Instead, they are signs of the mythic event and, in this fashion, perfectly parallel the verbal descriptions of the creation that shamans included in their mythic song cycles. As anthropologist Alfred Kroeber noted in 1957, although the Mojave may dream a mythic event or series of animal spirits pertaining to a song cycle, they do not say that they dream the events or spirits, per se, but instead claim that their vision is of the pattern of the myth or spirit. Just as their graphic depiction's of the creation of the world were expressed simply as entoptic designs, so too the verbal accounts in their song cycles were often simply a combination of a few words or lines that lacked any obvious narrative information. In both cases, this resulted because everyone and the songs knew the actors and events in the myth and petroglyph motifs were just the idiosyncratic signs of the mythic events and required no detailed illustration or recitation.