Culture and Ecology of Chaco Canyon and the San Juan Basin

252 Chaco Project Synthesisavailable ceramic types and a few tree-ring dates,Powers et aI. (1983) could not determine which camefirst-the great houses in Chaco Canyon or those in theoutlying communities.At least nine new Chacoan structures appearedby Late Pueblo II (A.D. 975 to 1050); seven werelocated in areas that had evidence of previoussettlements or communities (Figure 8.3).The largest number of new Chacoan structures(n= 19; Figure 8.4) were assigned to the Early PuebloIII period (A.D. 1050 to 1175). During this peak:construction period, some were built in each decadebetween A.D. 1058 and 1130. This increase in constructionparalleled developments in Chaco Canyon(Lekson 1984a; R. Powers et ai. 1979). Distributionof pottery types indicated that Chaco McElmo Blackon-whitewas rare on sites in the southern half of theSan Juan Basin, where Puerco Black-on-white andWingate Black-on-white were the diagnostic types. Inthe Chuska Valley, the predominant types wereToadlena Black-on-white, Chuska Black-on-white, andNava Black-on-white. To the north of the San JuanRiver, types in the Mesa Verde series were more common.The formal road network that led to the fringesof the Chaco Basin, where a number of resourceslacking in Chaco Canyon would have been moreabundant, probably came into existence during thisperiod.There was a considerable decrease in occupationat outlying communities during Late Pueblo III (A.D.1175 to 1300) (Figure 8.5). During the first half ofthis period there was no new construction of Chacoanstructures. A slight increase in occupation and somenew construction occurred between approximatelyA.D. 1225 and 1300. However, late reoccupationnorth of the San Juan River and at Guadalupe ruin didnot look Chacoan (R. Powers et ai. 1979).R. Powers et aI. (1979) and Marshall et ai.(1979:337) concluded that public architecture developedgradually throughout the entire San Juan Basin.After A.D. 950 and continuing to around A.D. 1200,Cibola-series ceramics were present in areas where anumber of small masonry structures were found near"public" buildings (great houses and great kivas)(Marshall et al. 1979). Some communities had reservoirs,and a few had irrigation facilities. Near publicstructures, road segments were often visible. Becausesome communities existed prior to the construction ofa Chacoan building, the cause for the establishment ofa community could not be attributed to events inChaco Canyon (Powers et ai. 1983). The appearanceof public architecture during the Early Bonito phasewas not the result of colonization by elite from ChacoCanyon; rather, Marshall et ai. (1980:337) proposedthat productive communities and alliances amongpeople "on the fringes of the Chacoan interactionsphere made the impressive developments at ChacoCanyon possible." Because most people in communitieslived in small house sites, construction ofpublic architecture represents community efforts tobuild and maintain these buildings. In Chaco Canyon,the large public structures may represent publicfacilities used by several distant communities. TheBonito- and McElmo-style great houses were thoughtto represent storage facilities for two reasons: first, itis in these structures that large quantities of unusualgoods are found; and second, the thick walls of thesebuildings would provide insulation against rapid temperaturechanges, and discourage pests. The lack ofburials at great house sites versus their presence insmall house sites also supports this hypothesis.Marshall et ai. (1979) examined the spacing betweenChacoan communities and the types of soils onwhich they were located. Except for the Hogbackcommunity, all Chacoan sites with public architectureand small houses within a community were locatednear productive soils. Some large structures wereisolated, in which case they were associated most oftenwith roads. Some of the road-associated sites werelocated away from productive soils; and none of theroad-related sites had an associated great kiva. Here,great houses were small, and sites that could beconsidered part of a local community were few. Thesesmaller settlements were thought to have functioned aslogistical road-related sites rather than distinct communitiesthat supported a large social group. Theaverage spacing between public structures on thenorth-south roads was approximately 14.5 km, orabout a day's walk. In the southwestern part of theSan Juan Basin, communities averaged about 9.7 kmapart.Agricultural areas in the Red Mesa Valley andDutton Plateau were packed with farming communities;yet all the best lands were not fully utilized