Comparisons to Archaic Assemblages: Bifaces

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Despite past and continuing practices of lumping these later materials with those of the Archaic, there are clear quantitative and qualitative distinctions between them. Canutillo complex bifaces and their resulting debitage may look superficially like Archaic materials simply because they are formal tools. The discontinuation of a formal tool technology with the advent of the ceramic period has led to the erroneous grouping all formal tools into earlier pre-ceramic stages. Yet with the rise of mobility in the late prehistoric a formal biface-based technological organization appears again and a variety of measures allow these to be distinguished from their earlier counterparts. The goals of production were similar (biface-oriented technologies aimed at producing durable cutting implements), but the products are quite different. When comparing Archaic bifaces to those of the Canutillo complex one is immediately struck by basic differences in technology, visual quality, and a number of physical attributes including the freshness of the flakes scares on the Canutillo material. These differences as discussed below include: (1) differences in materials used (silicified limestone and fine-grained basalt for Archaic versus fine-grained silicates for Canutillo along the same drainages), (2) differing degrees in patenation and dullness versus sharpness of edges related to age, (3) stylistic differences including clunky, thicker, and asymmetrical Archaic bifaces versus the symmetry, high quality flaking, and thinner Canutillo ones as reflected through visual inspection as well as in number of marginal flake scars, (4) the distinctiveness of shape between the thin ovate or leaf-shaped Canutillo bifaces versus San Pedro bifaces, for example, that are triangular in form, with a broad or expanded base that tapers toward the opposing end, and (5) the distinction of Canutillo complex and the Archaic San Pedro and Chiricahua materials is also apparent with regard to biface length, width, and thickness.

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Weathering 

When opening any drawer of the catalogued materials from the Cochise Culture type sites (Sayles' referent for Archaic period sites) at the Arizona State Museum the clarity of the differences are immediately apparent. For example, San Pedro stage and Chiricahua stage materials from the Fairbank and Cave Creek type sites, respectively are heavily patenated, with rounded edges that have been dulled with age (Figure 6). These represent the latest materials from the Cochise culture sequence; earlier Archaic materials are even more weathered (but few bifaces are included in the collections). In comparison, protohistoric tools are fresh looking, often with a bright luster to the surface and with relative sharp edges. Even on sites with both prehistoric (Archaic or ceramic period) and Canutillo complex materials, the protohistoric tools and debitage consistently show substantially less weathering than their earlier counterparts, whether in buried or surface contexts. This is not surprising given the late dates that are produced on sites containing these unweathered artifacts from across the region.

Materials Used
Material types used were also distinctive. Archaic-age artifacts from the San Pedro Valley and much of southeastern Arizona are often made of silicified limestone and fine-grained basalt whereas protohistoric Canutillo complex bifaces are made of fine-grained cherts, chalcedonies, and fine-grained rhyolites. Through time these materials seem to be locally procured, including the red, orange-tan, and gray cherts that are found in neighboring mountain ranges along the San Pedro, in tributary canyons, and in lag gravels. The selection of distinctive material types in different eras likely relates in part to the quality of the desired finished product; large pieces of finer-grained materials were needed to achieve the thin final protohistoric specimens that were produced through fine bifacial flaking.

Style and Symmetry
Stylistically the symmetry of the protohistoric Canutillo complex bifaces is immediately apparent, whereas the Archaic bifaces are often clunky and asymmetrical. The difference in flaking quality and final product probably relates to the use of Canutillo complex bifaces as knives and perhaps as flake cores, whereas the thicker Chiricahua stage and San Pedro stage Archaic ones probably functioned as cores for the production of flakes (see Sayles and Antevs 1941: Plate Xd; Haury 1975:272, Figure 56d, 276, Figure 57d). The thinner San Pedro stage bifaces (that were not projectile points) were probably used as cutting implements (Haury 1975:269, Figure 54e,f; also see Huckell 1984:Figure 5.23k,l,o; Huckell 1995:55, Figure 4.2d,e), but these are not as finely flaked, nor as thin, or as symmetrical as the later forms (Haury 1975:265, Figure 52f). Moreover, Canutillo bifaces are alternately flaked on opposite sides of the tool so that the edge is wavy and produces a distinctive and durable
cutting edge.

Flaking Quality
This difference in flaking quality is quantifiable in the amount of flaking on tool surfaces, which differs substantially between Archaic and Canutillo protohistoric bifaces. This is apparent with simple visual inspection but can be quantified with a measure of number of marginal flake scars per a 10 mm linear area along a randomly selected portion of the margin. Figure 8 illustrates the differences in quality of manufacture and investment in flaking that characterize this tool form through time. San Pedro bifaces-those from the Archaic that are most similar to the Canutillo complex-average around 1 to 2 flake scars per 10 cm area whereas Canutillo bifaces have three to five. Finer flaking likely relates to the desire to maintain flaking control so as to produce the desired edge on and thinness to the tool.

Shape
The distinctive ovate or leaf-shaped form of Canutillo bifaces is one of the most telling attributes, particularly when combined with specimen thinness. A subset of San Pedro bifaces, those that probably functioned as knives, is most similar to Canutillo bifaces with regard to their thin profile. But as shown in Figure 9, these San Pedro bifaces are triangular in form, with a broad or expanded base that tapers toward the opposing end. Plus, while Chiricahua bifaces trend toward an ovate or leaf-shaped form, these are substantially thicker than their protohistoric counterparts, with deep multidirectional negative flake scars that are consistent with these forms being used as cores or heavy implements. Many of the thick San Pedro bifaces are also ovate but, like Chiricahua bifaces, they lack symmetry in flake scar orientation and probably functioned as cores or more durable forms of tools. The thin Archaic and Protohistoric bifaces that possess attributes indicative of their use as knives (e.g., thinness of margins consistent with cutting and acute edge angles), are distinctive in outline form as compared to the Protohistoric ones. Although most Archaic knives are broken, the tapering nature of their margins is indicated on the fragmentary specimens and is confirmed in the more complete forms. 

 

Canutillo bifaces tend to fall into at least two shape categories suggesting that there may be grounds for further subdivision. These differences probably relate to how they were hafted. One variety has an ovate outline (with its greatest width near the midsection) and two pointed ends, and may have been hafted as shown in Figure 10a. The second is pointed on one end and blunt or flattened on the other suggesting hafting from the end (Figure 10b). Evidence for these differences in hafting is provided in the negative flake scars on the surface of these specimens. An often-visible feature of these bifaces is a slight indentation on one or both margins, where the edge was blunted so that the sinew would not be severed. In addition, flake removal on the blunt end of some specimens indicates preparation for hafting. More obviously, the face of the double pointed bifaces is often thicker near the center of the tool where flakes seem to have been intentionally terminated (hinged out) in the center to form a thicker section to hold the hafting in place. This placement is consistent with the indentations on the margins. In some instances, instead of being raised one or more large flake scars will decrease the thickness of the surface, leaving an adjacent raised surface, which accomplishes the same result (Figure 11). This effect can be quite subtle and were it not for photographs showing hafted examples (Figure 12) this attribute might go unnoticed. 

 

It is likely that these bifaces were used as knives, judging from the hafted examples, the vaguely sinuous margins, and the acute edge angles. This inference that is consistent with the historic record that notes the use of knives among mobile groups encountered in southern New Mexico and Texas along the Rio Grande (Ayer 1965:14; Hodge and Lewis 1990), as was discussed briefly above.

Metrics
As Figure 13a-c shows, basic metric differences between Canutillo and Arizona Archaic (the original Cochise culture complex type site) materials demonstrate they differ in more than visual qualities. The sample size is still small because the protohistoric complex has only recently been defined. Also, regrettably, these fine tools are the type of items that have been removed from sites by collectors because they are pretty, valued, and visible. Although these types of tools have been found in sound archaeological contexts, many specimens are known from collector's riker mounts or donated unprovenienced finds in museum drawers. Some, like those from Ventana Cave and Pintada Rockselter, are included in mixed assemblages that have not yet been culled. Regardless of these difficulties, the metrics demonstrate discernable differences between these protohistoric bifaces and those attributable to the Archaic period. Thus, for those not convinced of the difference between Canutillo and the Archaic by the aesthetics of the tools, the measurements provided in the accompanying figures supplement the visual qualities in characterizing the differences.

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The distinction of protohistoric Canutillo and the Archaic San Pedro and Chiricahua materials is apparent in these figures. With regard to biface length, width, and thickness tangible differences can be seen graphically (Figure 13a-c). While Canutillo and Chiricahua bifaces are most similar with regard to length and width, they are most different in thickness. San Pedro and Canutillo bifaces are most similar in thickness, as is consistent with their inferred use as cutting implements, but they diverge widely in length and width. 

 

Figure 14 illustrates the relationship between biface length and thickness. From the constructed index (length divided by thickness) it is possible to see that Canutillo complex bifaces are at the same time longer and thinner than their Archaic counterparts and in this relationship there is little difference between San Pedro and Chiricahua stage materials. Canutillo complex bifaces are so distinctive because they are relatively thin for their length as compared to San Pedro and Chiricahua stage materials. 

 

By a variety of measures and considerations the Canutillo complex materials are distinctive from the Archaic assemblages that are found in the same geographic areas, often in similar environmental and physiographic settings, and many times on the same multicomponent sites. These bifaces are but one of the many tool types found on these Canutillo complex sites but they serve as an example of the uniqueness of this protohistoric assemblage from the Archaic assemblage with which they have been confused.