Culture and Ecology of Chaco Canyon and the San Juan Basin

6 Chaco Project Synthesispainted Escavada, Gallup, and Chaco black-on-whites,as well as carbon-painted McElmo Black-on-white.The presence of carbon-painted wares had beenattributed to colonists from other areas (Rawley1937b; Judd 1964), as well as to importation (Dutton1938; Kluckhohn 1939a). Gordon Vivian andMathews (1965:75) argued against a rapid successionof pottery styles that quickly supplanted one another;they proposed that the mineral- and carbon-paintedwares coexisted in the area for a considerable periodof time, and that the carbon-painted wares eventuallywere adopted over a wide area due to a shift indecorative materials and styles. The concept of shiftsalso accounted for the heavier design elementsemployed in the later Mesa Verde period decorativestyle (Vivian and Mathews 1965:83). The role ofmigration in Pueblo history and the meaning of theMcElmo period (when carbon-painted ceramics anddimpled masonry are introduced) in Chaco Canyonwere two issues that needed clarification (Vivian andMathews 1965).Because several large and small sites were contemporaneous,Gladwin's (1945) progression from theRosta Butte phase through the Classic Bonito phasewas incorrect. Z. Bradley (1971) partially supportedGladwin's (1945) proposition regarding a northwardmovement of population initially in Basketmaker III,then sequential development from the later Rosta Buttephase seen at the small houses to the Bonito phase ofthe large houses. Bradley's excavation at Bc 236revealed a lO-room pueblo with an enclosed kivaconstructed of large, double-faced blocks that hadbeen pecked and smoothed and remodeling of a kivato accommodate a keyhole-like recess, as well as aninfant burial accompanied by a Mesa Verde Black-onwhitebowl in a remodeled room. Using data fromPierson's (1949) survey of small houses on both sidesof the Chaco Wash, Bradley concluded that theevidence from Bc 236 indicated a peaceful transitionof people from one type of living quarters to anotherduring this later period. He proposed that the originalChaco population moved out of their Hosta Buttehomes into great houses; and that incomingnortherners then utilized the Hosta Butte houses, aswell as building their own. In contrast, Voll (1964),who had excavated a Pueblo III house (Be 362) with18 rooms, three kivas, and two plazas constructedaround A.D. 1088 and remodeled around 1109,thought that Bc 192 (excavated by Maxon 1963) andBc 362 were less like typical Rosta Butte phase sites(Bc 50 and Bc 51) and probably belonged in theMcElmo phase. The mingling of McElmo and Chacoblack-on-white pottery did not suggest massmigrations. The proposition of an influx of peoplefrom the north or the San Juan River left manyunanswered questions. Row different were thepeople? Were their differences linguistic, ethnic, orwhat? How many groups actually lived side by side inthe canyon? At what point in time can distinctionsbetween/among groups be detected?To explain the differences in masonry typesfound at small sites and the Classic Bonito- andMcElmo-style great houses, Gordon Vivian andMathews (1965: 107 -115) proposed that there werethree contemporaneous types of communities or phasesin Chaco Canyon from the mid-A.D. 1000s to theearly 1100s. Both the Hosta Butte and Bonito phaseshad evidence for long-term development within thecanyon (see also Gordon Vivian 1965 :44-45). Peopleliving in Bonito-style houses had ties with the SanJuan tradition to the north; those in the Rosta Buttesites possibly had ties with the Little Coloradotradition to the south. The McElmo phase, on theother hand, was thought to represent an intrusion ofpeople from the north who had previously adopted, orthen adopted, some of the styles used by the Bonitopeople.Causes for abandonment of the canyon wereunresolved. Because tree-ring dates from Kin Kletsoindicated construction episodes in the late A.D. 1000sand early A.D. 1100s, a proposed drought with arroyoentrenchment (Bryan 1954) was not considered acompelling reason for leaving the area at the end ofthe eleventh century. Gordon Vivian and Mathews(1965) noted that there were no tree-ring datesindicating construction after A.D. 1124; yet an A.D.1178 + date on firewood at Kin Kletso indicated usefor another half-century. Evidence for the small, laterpopulation at Bc 236 and the Headquarters site, plusscattered sites in defensive positions on Chacra Mesa,suggested "either a continual movement of smallgroups of people or succeeding intrusions of smallgroups with varying trade relationships" (Vivian andMathews 1965:113).Proposed explanations for Pueblo development,growth, and demise were therefore based mainly on