The nodules were frequently reduced at the source and flakes occur throughout the source area, but no intensive reduction areas were located. Geologic map of the central part of the San Francisco Volcanic Field, north-central Arizona. USGS Miscellaneous Field Studies Map MF-1959. RSS6 295.12 441.57 9553.56 407.05 4.15 85.86 176.33 271.98 41.18 RS Hill . The nodules are similar to those from Sitgreaves, but not as eroded and therefore generally more angular.
Gray cortex predominates.
The glass however, is frequently blacker, more vitreous and a higher quality knapping obsidian. The fabric looks megascopically very similar to Government Mountain, but is not entirely aphyric. Secondary deposition occurs as slope wash into the Spring Valley Wash system, but the material is only transported a few kilometers south. Reduction of the nodules is very common and flake densities approach 100 per 5m 2 in places. Published references are the same as for Sitgreaves.