Tranquil Rockshelter, located near the headwaters of Terlingua Creek, was originally test excavated in 2007. Because the results were so promising, a CBBS crew, eight archaeological field school students, and several volunteers returned to conduct a full scale excavation. Over the course of the season, seventeen square meters were excavated in contiguous units to provide two long, perpendicular trench exposures.

While artifactual evidence at Tranquil indicates occupation as early as 3000 B.C., the bulk of the subsurface deposits date between A.D. 890—1620 (based on seven radiocarbon dates). The CBBS documented more than 35 features, including rock art panels, grass lined depressions, hearths, and roasting pits. Highlights of the recovered artifacts include a variety of Late Prehistoric projectiles, most notably Toyah arrow points. In addition, the sheltered setting preserved rare perishable items such as arrow shaft fragments, sandals, woven matting, and cordage. Of particular interest was the discovery of corn cobs, beans, and a structural remnant that appears to have been of jacal-like (wattle-and-daub) construction. These latter findings are all suggestive of ties to Late Prehistoric villagers in the La Junta district along the Rio Grande.

Only two miles east of Tranquil, Rough Cut Rockshelter was excavated in the summer of 2007. During this project, six and a half 1 x 1 square meter units were excavated, resulting in the recovery of over 20,000 artifacts, including 91 Perdiz points and point fragments and four pieces of obsidian—a stone type for which there is no source in the region, suggesting long-distance trade. Based on the high percentage of arrow points to other formal tools, and especially the abundance of arrow point stem fragments—which suggest re-hafting of arrows—it is believed that the site was most likely a hunting camp. Also supporting this idea, over 7,000 faunal remains were recovered, 1,000 of which were identified. Almost half were identified as rabbit.

Because of the significance of this site in terms of the uniformity of projectile point style and three tightly clustered Late Prehistoric radiocarbon dates (ranging from A.D. 1290—1450), an intensive lithic analysis was performed on over 13,000 pieces of debitage, analyzing each individual specimen for an array of different attributes. Specimens were then grouped into 123 different stone types and an SRSU geologist was consulted on issues of stone sourcing. A manuscript of the Rough Cut Rockshelter investigation is in progress.