Culture and Ecology of Chaco Canyon and the San Juan Basin

204 Chaco Project SynthesisRabbit ruin west). Be 50, a small site across theChaco Wash from Pueblo Bonito, also exhibited asimilar ground pattern (Truell 1986:Figure A.103).Tower kivas, a tri-walled structure, and some roadrelatedstructures appear. The class II events representedby construction at Tsin Kletsin, New Alto, andKin Kletso appear to be designed for storage. Lekson(1984a:269) suggested that this may represent a transferof function from the earlier great houses, whichwould make many of their rooms available for otherfunctions.Somewhat concurrently, a shift in the location oftrash disposal occurs (Lekson 1984a). Beginning inthe late A.D. lO00s and continuing into the earlyAD. 1100s, trash is placed in rooms rather than ontrash mounds. This trash contains many decoratedsherds and does not resemble the trash recovered fromlater rooms in Kin Kletso. Thus, the system exhibitssome change in events that has not yet been fullyexplained.To better understand the social implications ofgreat house construction episodes, Lekson (1984a:Table 5.1 and Figure 5.1) calculated the scale of constructionevents and plotted them through time (Figure6.3). There is a major difference between classes Iand II when compared with classes III and IV. Thelatter two included only three sites each and occurredonly after A.D. 1050. For all classes of events exceptclass II, the peak of construction occurred betweenAD. 1050 and 1100 (Figure 6.4).Class I events were the smallest, but they representthe largest number of construction episodes(N=59, or 41.3 percent of the person-hours). In thiscategory are room blocks represented by the initialconstruction at Una Vida, Pueblo Bonito, and PenascoBlanco; McElmo room blocks; and others (e.g.,incidental rooms, plaza-enclosing arcs). Althoughnone of these events occurred between AD. 960 and1030, a few were constructed prior to these dates, andmany appeared later. Sometime after A.D. 1020, itseems as if these were part of a constant constructionbackground, with one or two units being built everytwo to four years. The greatest number (20) of theseunits were built between A.D. 1080 and 1110.Class II events numbered 14 or 35.1 percent ofthe person-hours. Most events represent the buildingof room blocks between A.D. 1030 and 1080, but fourMcElmo structures constructed after A.D. 1110 areincluded. During the gap in this class of eventsbetween A.D. 1080 and 1110, five of the six largerconstruction episodes (class III and IV) occurred.Class III room blocks at Pueblo Bonito (II),Penasco Blanco (lIlA), and Pueblo del Arroyo (IIB)were built between A.D. 1050 and 1100. Class IVroom blocks represent additions to Pueblo del Arroyo(IIA) and Pueblo Bonito (VIB), and the constructionof one new great house, Wijiji, between A.D. 1075and 1110. Together, these two classes represent 25percent of the person-hours in all great house constructionwithin a span of 60 years. Lekson estimatedthat class III construction events took place approximatelyevery nine years, and that class IV events tookplace every seven to 10 years.Analysis of the labor needed to collect materialsand build great houses indicated that a fairly smallpopulation could have been organized in such amanner as to not compete with other duties, yet stillaccomplish the task. When considering the longdistanceacquisition of numerous primary beams(vigas), plus securing the secondary beams (latillas)and layers needed to complete the roof, even thelargest construction episodes after A.D. 1075 couldhave been accomplished by a popUlation of 5,211individuals-a number remarkably close to Hayes's(1981) estimates of 5,600 for this period (Lekson1984a:262), but considerably above Windes's(1987a[l], 1993d) recent estimates. If the large sitesfunctioned as storage facilities or public architecture,then the number of inhabitants is greatly decreased.Depending on the amount of available time and thesize of populations, there may have been difficultiesduring periods when the most massive constructionevents took place. Lekson (1988a: 129) estimated thatonly 425 individuals lived in great houses. Hethought that this still represented a large number ofleaders or elite living in the canyon settlement. Asmaller population estimate would put more pressureon the small house population that probably constructedthese buildings.The large increase in labor estimates for the classIII and class IV construction events, and (with theexception of Wijiji) the focused expansion of greathouses predominantly in the central area of the canyon