44 tipi rings and circular arrangement of stones. The sites were located along canyon rims and at canyon heads for short periods of time, likely only for several days to several weeks. The limited material goods found include beads made of imported turquoise, cord-marked pottery, imported San Lazaro Glaze Polychrome pottery made during the Ancient Pueblo People Pueblo IV Era and, in one site, Taos Pueblo or Picuris Pueblo mica tempered pottery made after A.D. 1500. Rock art and solar markings The south canyon walls of Picture Canyon contain rock art, red and black pictographs and human and animal petroglyphs, that were likely made by Plains Indians in the 17th and early 18th centuries. Horizontal lines of writing were found there, similar to 50 sites in Oklahoma and southeastern Colorado, which have been translated to include solar, planting and travel related information. Markings in the walls of Crack Cave were made more than 1,000 years ago which are illuminated by rays of the sun during the spring and autumn equinox. Free tours are conducted by the National Forest Service on equinox dates in March and September. References External links Picture Canyon, National Forest Service Ancient Pueblo peoples rock art Archaeology of the United States Archaeological sites in Colorado Canyons and gorges of Colorado Grasslands of Colorado Grasslands of the North American Great Plains Landforms of Baca County, Colorado Landforms of Las Animas County, Colorado Landforms of Otero County, Colorado National Grasslands of the United States Plains Woodland period Protected areas of Baca County, Colorado Protected areas of Las Animas County, Colorado Protected areas of Otero County, Colorado Protected areas of Colorado Protected areas established in 1960