The larger patterns revealed by these surface collections can be summarized as follows. First, the Ob1 material appears to have been available in the largest sizes in the Maymeja area of the Chivay source. Second, knappers in the Block 2 area appear to have made greater use of the Ob1 material, but for some reason they had smaller starting nodules as is evident from the smaller artifacts with ? 30% cortex. The fact that cortical materials in the immediate consumption area have much smaller sizes than those being derived from the Chivay source suggests that the largest Ob1 nodules were notbeing consumed in Blocks 2 and 3, and one possible explanation is that they were being exported to the larger consumption region.

We can gain further insights into the differential use of obsidian through the patterns associated with Ob1 and Ob2 material. These data relate to question of the importance of transparent, homogeneous obsidian. In Chapter 3 the relative use of Chivay and Aconcagua obsidian at Asana was discussed because it was inferred that later pastoralists may have been satisfied with Aconcagua material because they were less concerned with the aesthetic qualities of obsidian and more focused on its utility for shearing and butchering. The assumption being that visual quality was less significant for utilitarian applications. For projectile point manufacture, however, Ob1 obsidian appears to have been much preferred by pastoralists. In the pre-pastoral Archaic the use of homogeneous, Ob1 obsidian for projectile point manufacture was less prevalent.

The use of Ob2 can be considered in terms issues of access, aesthetics, and economy.

(1) Access:The obsidian with heterogeneities was found scattered across a larger region on the east and south-east flanks of Hornillo, as well as intermittently on surface elsewhere in the Blocks 1, 4, and 5 survey areas. In contrast, the Block 1 Maymeja area was the only zone with large nodules of Ob1 obsidian available, and under modern conditions the majority of these are beneath a layer of ash. These data suggest that obsidian procurement during the Middle and Late Archaic may have involved more frequent exploitation of surface materials simply because these groups did not have knowledge of, or need to, excavate to obtain Ob1 obsidian. Alternately, during the Terminal Archaic and onwards, quarrying for clear obsidian in the Maymeja zone was developed and greater quantities of clear obsidian were circulating.

(2) Aesthetics:The Ob1 obsidian appears, to modern eyes, that it would have had more value in cultural and prestige related functions. From a biological adaptationist perspective, Ob1 obsidian has higher costly-signaling value (Craig and Aldenderfer In Press), and one would expect both hunter-gatherers and pastoralists to emphasize obsidian free of heterogeneities for its signaling value. As was discussed previously, exchange of objects between individuals or groups as symbolic tokens is documented among hunter-gatherers as well as pastoralists. However, during the pastoralist period social hierarchy increases rapidly and under these circumstances it is possible that the social importance of Ob1 obsidian to a competitive leader during a period of dynamic transegalitarian is considerable.

(3) Economics:Pastoralist producers of projectile points could afford to be selective in the material that they used because projectile points were not necessarily "consumed" by subsistence hunting. If obsidian points are to be used as the principal means meat procurement, points will be broken and lost during hunting forays and there is therefore a need for less costly and easily replaced projectile points. During the pastoralist period, however, hunting for meat is supplementary to the meat available from the herd. Therefore, projectile point use becomes more discretionary because points are used for activities such as non-essential hunting, warfare, or symbolic exchange.

An additional economic component to the use of clear obsidian concerns the economy of projectile point production. Evidently obsidian was predominantly used for Series 5 (concave base, triangular) projectile points styles, and Series 5 points are much smaller on average than other projectile points. When only unbroken projectile points are considered, the mean weight of series 1 through 4 projectile point types is 5.69 g, sd = 4.92, while for Series 5 points the mean weight is 2.08 g, sd = 1.80. On average, Series 5 points are 2.89 times smaller than the other point styles, and therefore one could produce many more projectile points from a single nodule of clear, Ob1 obsidian if one were to make Series 5 points as opposed to an older, larger type of projectile point.