point styles as specific time markers. The sequence contains the Gatecliff series dating from ca. 4000 B.C. – 1000 B.C., the Elko series from ca. 1300 B.C. – A.D., Rosegate series from ca. A.D. 700- A.D. 1300, and the Desert series from ca. A.D. 1300 – 1850. Other stone tools found include metates, palettes (small grinding stones), handstones, and workedturquoise. Several turquoise mines exist throughout the Monitor Valley which could provide the turquoise source for Gatecliff; Indian Blue Mine is the best known mine located 3 miles south of Toquima Cave. Gatecliff Rockshelter also produced over 400 incised stones – the largest known concentration in the New World. Incised stones include any portable stone purposefully modified with cuts or lines or holes. The incised stones at Gatecliff Rockshelter include simple to complex motifs of lines, rows, chevrons, circles, and striations. Incised stones have also been considered as a means of dating rock art styles. Approximately 35 perishable artifacts were recovered in Gatecliff Rockshelter; these include 11 basket fragments and 18 pieces of cordage. The preferred material for cordage is Artemisia (genus) and Salix sp. for baskets. According to James M. Adovasio, the preference for willow, despite its sporadic distribution across Monitor Valley, comes from its durability, flexibility, consistent thickness of the bark, and the lack of lateral twigs. The techniques used in the Monitor Valley include simple twining, open and close diagonal twining, and coiling. In addition, the excavations at Gatecliff Rockshelter recovered 17 shell beads and 4 ornaments. The shells include Olivella (gastropod), Haliotis cracherodii, and Haliotis cracherodii.[15] Other materials include mica and stone. Additional artifacts found at Gatecliff Rockshelter include wooden artifacts (promontory pegs, firemaking tools, bow fragments, etc.), bone artifacts (bone beads, awls, and tubes), a glass bead (possible trade bead), a few pieces of ceramic sherds, and some incised clay objects. Rock art The rock art at Gatecliff Rockshelter includes white, red, yellow, and orange pigments; black was not used on the walls but decorated small stones. The paint materials are derived from local sources. Of the images, fifty-three were recognizable with 13 different motifs and some unidentifiable blotches. The important images include human anthropomorphs and linear arrangements. Cupule motifs account for 11 percent of the images, handprints 9 percent, and bisected chevrons 7 present. References External links Gatecliff Shelter, Nevada Gatecliff Formation Life in a rock shelter Rock shelters in the United States National Register