The 1970 Discoveries
This brief introduction, although a selective and much abbreviated account of present archaeological, geological and climateological knowledge of post-Pleistocene times in southeastern Arizona, serves as a background to a description of last summer’s finds nearDouble Adobe. Initial survey of the Cochise College-Double AdobeHighway right-of-way early in 1970, located a single archaeologicalsite on a ridge paralleling South Frontier Road, south and west ofWhitewater Draw. Scattered chipped stone, mano and metate fragments, and a few projectile points on the surface led to its provisional identification as belonging to the Chiricahua stage of the Cochise culture. During subsequent excavation of the site, test trenches were placed perpendicular to Whitewater Draw on the highway right-of-way for the purpose of finding further evidence to substantiate the contemporaneity of extinct animals and the Sulphur Spring stage (see Figure 1). Although the analysis of evidence uncovered by the trenches is by no means completed, our knowledge of the early post-Pleistocene is being greatly enhanced.
During twelve days early in September, 1970, while most of the field crew were excavating on the Cochise culture site, seven backhoe trenches were placed adjacent to Whitewater Draw on the floodplain below the surface site. Although the main purpose of the trenches was to explore for evidence of buried cultural material associated with the Sulphur Spring stage of the Cochise culture and any evidence of its contemporaneity with extinct fauna, evidence ofpast geological events and paleoclimate was also being sought.
During the first phase of the backhoe operations while six trenches were being excavated roughly at right angles to the draw, bones of recent domesticated animals were recovered near the surface, bison bones were found scattered in a limited quantity throughout the dark clay immediately below the shallow, recent aluvium and a small mammoth bone splinter was recovered from a gravel lense within a rusty sand layer which underlies the dark clay. Three stone flakes that were probably man-made were later found in thesame trench (Trench E) only a few centimeters from the mammoth bone splinter. Unfortunately, the position of the flakes in a gravel lense with the mammoth bone splinter that appeared to have beenstream-rolled is not a positive indication that they were deposited at the same time. Remains of a mammoth, represented only by a splinter of bone, and the flakes could have been deposited thousands of years apart and come into association from stream action mixing the deposits. Another trench (Trench C) yielded a mano in the rusty sand matrix, the same layer in which Sulphur Spring stage artifacts are supposed to occur, but no other artifacts or associations were found. Near the completion of the trenches, pollen and charcoal samples were taken from several areas of the exposed strata, analysis of which is adding to our present knowledge of the age and plant types of past environments along Whitewater Draw during times when the area was inhabited by man. After backhoe work was finished in the six trenches, stratigraphy was recorded in four of the trenches (Trenches A, B, C, and E) and it was suggested that one additional trench (Trench G) be placed perpendicular to the longest existing trench (Trench A) for the purpose of gaining a three-dimensional picture of the geology.
As Trench G was begun, excavation four meters from its intersection with Trench A revealed one complete long bone, several vertebrae and another long bone fragment of a mammoth. Within a short period of time, larger equipment than used previously widened Trenches A and G to expose an area around the find (Figure 2). As soon as possible, hand excavation resumed and revealed what have been tentatively identified as two humeri and fwo radius-ulnae, unarticulated but in close proximity to one another, several vertebrae, fragments of a scapula and other mammoth bone fragments scattered throughout the same level in gravels underlying the rusty sands. A study was made of the deposition of the bones and their relationships to the mano previously found in a rusty sand matrix and three flakes uncovered in a gravel lense in Trench E. According to Vance Haynes, geological specialist in early man sites and now at Southern Methodist University, both the mano and the flakes appear to be stratigraphically higher than the mammoth bones. Charcoal samples for radiocarbon dating were recovered from the vicinity of the bones with the aim of placing the remains in chronological perspective with regard to natural and cultural events that have taken place in southeastern Arizona.
Near the close of the excavation a small exploratory trench (indicated by the arrow in Figure 2) in the main pit revealed the bank of an ancient arroyo that was probably in existence at the time during which the mammoth had died and whose remains were deposited in the arroyo gravels. A few small mammal and bird bones collected from this excavation will supplement knowledge of the paleoenvironment during the time mammoth roamed the Sulphur Spring Valley and give a more accurate picture of the setting in which the Cochise culture developed.
The Fairchild Site
Although excavations of the mammoth remains near White· water Draw did not reveal any clear associations between extinct fauna and the earliest stage of the Cochise culture, results of radiocarbon dating and pollen analyses will add to current knowledge about Pleistocene extinctions and the local environment during andprior to occupation of the nearby Cochise culture site, Ariz. FF: 10: 2 (Arizona State Museum designation for the Fairchild site). First impressions of the Fairchild site were dominated by its size. Surface clusters of firebroken rock and scattered chipped stone covered anestimated area of 50,000 square meters on an almost imperceptibleridge above the narrow floodplain of Whitewater Draw. The highway right-of-way bisected the site and joined Double Adobe Road at its junction with the Elfrida Cutoff.
Although the entire site was covered with a light-colored sand deposited by sheet erosion, excavation of several five-meter squares was begun on the highest portion within the right-of-way for the purpose of determining areas with the deepest occupational refuseaccumulation (Figure 3). Such areas would yield the best evidence for length of aboriginal occupation and changes through time of the material culture. Artifacts and features, such as fire hearths, from the surface of the site could be placed on a rough time scale onlythrough comparison of stylistic elements of similar cultural items which had been recovered from a known stratigraphic context in the excavated areas.
The first test excavations revealed clusters of manos, firebroken rocks, and other stone material, as well as scattered small animal bone fragments, projectile points and chipping waste, all of which were buried in a dark layer of midden. Fourteen contiguousfive-meter squares were eventually opened in what appeared to be the area of deepest midden accumulation. In some instances, the depth of occupational debris extended to forty-five centimeters below the surface, the base of which was determined by the surface of a thick layer of calichified clay. Test excavations to a depth of aboutthree meters below the surface revealed the considerable depth of the sterile clay and diminished the possibility of’ Cochise culture artifacts occurring below it. Upon completion of the large excavated area, forty-seven features had been uncovered and a great quantityof artifacts collected that had been scattered throughout the midden. Of the features recorded, most were clusters of mano and metate fragments, firebroken rock, burned caliche nodules that may have been used in cooking processes, small animal bone fragments, somechipping waste and a few scrapers, knives and projectile points. One of the features was a shallow depression in the sterile clay with a diameter of nearly two meters, from which a large amount of burned animal bone fragments and a few firebroken rocks were recovered. Although it was the only such feature recorded during our excavations and there is little comparative data in published archaelogical accounts of the Cochise culture, the depression appears to have been used as a roasting or cooking pit. What is provisionally defined as a small storage pit was located about four meters from the shallow roasting pit. Unfortunately, the storage pit had been badly disturbed by rodent activity, destroying its original shape and any possibility of recovering a pollen sample from which some indication of the former contents might have been postulated. Surrounding the top of the pit was a very hard packed surface which could conceiv died and the nature of the environment during the time of its death. No artifacts were found with the mammoth bones and it remains highly questionable that its death was caused by man. Previous pollen analyses of sediment from Whitewater Draw indicate that at the close of the last Glacio-pluvial Period, about 10,000 years ago, the Sulphur Spring Valley was grassland, bisected down part of its length by a perennial stream that was probably lined with cottonwoods and other trees characteristic of a Riparian environment (cf. Sayles and others 1958: 21, Martin 1963: 36). The ensuing period, until the latter part of the Chiricahua stage, probably became increasingly arid or perhaps saw a shift in the seasonal rainfall that would account for discrepancies between the geologic and fossil pollen evidence of past climates. At any rate, some areas in the southeastern Arizona-southwestern New Mexico region have shown archaeological evidence for the beginning of cultivation and the following gradual spread of domesticated plants through the San Pedro stage of the Cochise culture.
The Fairchild site was probably occupied near the end of the Altithermal Period and during a time when knowledge of cultivated crops was on the increase. In fact, inhabitants of the site may have known about domesticated plants, even though present evidence does not indicate use of cultigens on the Fairchild site. Pollen extracted from the grinding surfaces of metates recovered from the site appears to reflect the use of Chenopodiaceae, Amaranthus and some grasses with evidence totally lacking for maize or other cultigens. It is conceivable that the inhabitants of the site were cultivating or encouraging plants in the Chenopod family because of the unusually high frequency in which their pollen grains were encountered during the analysis, but their prevalence may also be due to disturbed soil conditions inadvertently caused by everyday activities of the former human occupants.
The absence of any evidence of permanent or semi-permanent structures at the Fairchild site and the rare occurrence of storage pits and frequent presence of what have provisionally been defined as grinding stone caches, suggest that the site was inhabited seasonally. The relative abundance of Chenopodiaceae pollen in one storage pit and on the surfaces of metates intimates the use of plants common only during and after the late summer rainy season. Assuming the rain fall patterns of 3,000 to 5,000 years ago were similar to those of today, the pollen evidence would argue for a late summer and possibly fall occupation of the site. An additional analysis of stone material used on the site and possible source areas that is presently under way, may give clues in the direction of finding areas in nearby mountains and slopes with which the former inhabitants of the Fairchild site may have had contact. Further analysis of features and the artifact inventory recovered from the site will give us a better idea of the ways in which Cochise culture people exploited the environment, but only excavation of other similar sites in southeastern Arizona will provide the evidence needed to establish the seasonal pattern of migration of these people and make clearer the subsequent transition to a settled way of life.