Graph showing shift in raw material texture for projectile points between Paleoindian and Early Archaic periods in the western Trans-Pecos. Fine-grained materials include chert, chalcedony, and obsidian; medium-grained materials include coarser cherts; and coarse-grained materials include various igneous and metamorphic rocks as well as limestone. Adapted from Miller and Kenmotsu 2004, Figure 7.12.