San Dieguito Ceramics
Plate 10. Pitcher Lips and Grooved Sherds
a,b. Red-oo-Tan pitcher lips; c-f. Grooved sherds
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organizing this data in a fonn more or less compatible with other ceramic data from Cihuauin. All major classification categories recognized by Fowler and Bruhns are present at San Dieguito; differences in defmitions of the minor local categories exist. Some kinds of pottery that Fowler calls Nicoya-like from the WCC are not represented in the San Dieguito collections.
Relationship of Classification Categories to Selected Attributes
Each investigator working at CihuaHin has been impressed by the amount of variability within classification categories and by the fluid way in which individual variables cross cut the classification categories. A modal analysis of selected variables gives a quantifiable basis for assessing variability within classification categories. It identifies and quantifies crosscutting variables and, most imponantly, it gives a different and more sensitive ordering of the data with regard to factors that might be expected to reflect socioeconomic differences within the site. Although there is as yet no comparable infonnation from other parts of the site, the results of the modal analysis provide clarification about the nature of the problems involved in classification and point the way for future studies. Unless otherwise noted, the following observations and inferences are based on coded infonnation of the Random and Rim samples. Only infonnation on ceramic vessels is included here.
Slip Combinations
Tan slips occur in conjunction with white and/or red slips on both painted and unpainted pottery. Tan slips also provide the background
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for red designs in Tamoa Red-on-Buff, to use Fowler's designation. Fowler and Bruhns virtually ignore the role of tan slips in the combination slipped vessels. It is unclear whether San Dieguito pottery actually is aberrant in having so many combination slipped vessels, or whether those authors regard a tan slip as ubiquitous background noise. I suspect the latter, and Fowler, who had an opportunity to study the San Dieguito collections in Calgary, agreed that he had considered tan slip to be a differentiating variable only when it was not found in combination with other slips or painting. Depending on the status given to the tan slips, monochromes could become bichromes, bichromes could become trichromes, and so on. A great deal of visual variability could be achieved by differential placement of one or two slips on the interior, the exterior, the basal interior, carrying a slip band over the rim, and the addition of horizontal lines and other designs. Cihuatan potters seem to have employed combinations of slips with a great deal of freedom, thereby producing variability within the classification categories recognized by archaeologists as well as a great deal of overlap between those categories.
Stylistic Variability
We did not code for style or design motifs because so few sherds in the two samples carried relevant infonnation. The following descriptive remarks concern only the painted pottery presumed to be of "local" manufacture for which stylistic tendencies can be identified. Not included here are the more idiosyncratic designs or the Plumbates and "Nicoya-like".
The painted pottery presumed to be of
"local" manufacture shows the same mix-and-match quality that characterizes the ceramic assemblage more generally. This effect is undoubtedly intensified by the scarcity of complete or reconstructable vessels in the San
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Dieguito collections, and strong correlations may emerge in the future between classification categories and decorative style. Nevertheless, considerable overlap of styles across the classification categories can be demonstrated, as can some central tendencies of style within particular classification categories.
Horizontal lines tend to characterize the unnamed Black-on-Red bowls but are not confined to that subgrouping. Venicallines from the lip or venical panels joined by a horizontal line are most common in white background polychrome bowls but the vertical lines, at least, are found on Black-on-Red bowls. Naturalistic designs recognizable as faces, feathers and so on are vinually limited to the red (and white?) background polychrome tulip-shaped vessels, but a "reed-bundle" design served as the basal design in a Black-on-Red bowl. Although the polychrome designs of the red and white background tulip-shaped vessels are quite distinctive, the same vessel form occurs with an identical red background on which Bandera (or very similar) designs are painted, as well as in a polished brown.
Form and Size
On the basis of descriptive data and personal familiarity with the collections, we felt that, except for the Coarse category, form was not closely correlated with classification categories. To get a more objective statement of the strength of the relationships between form and classification, our statistician ran -first a Chi Square on the rim sample, and then a Cramer's V test (both are pan of SPSS).
The Chi Square results show that relationships between form and classification categories had only one chance in 10,000 of being due to chance. The strength of the relationship, however, is not given in that test.
Cramer's V test allows the strengths of the
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relationship to be evaluated. In this test, a result of 1.00 demonstrates that the relationship is 100%; if Cramer's V is 0.0, then no relationship exists. For the whole sample (including missing data), Cramer's V is .24 for the relationship of gross vessel form to classification categories.
This indicates a very weak relationship. By ignoring missing data, this rises to .30, which is still weak. For the specialized form coding, Cramer's Vis.41 including missing data. When missing data are excluded, this decreased to .34.
The strength of the relationship is stronger for the more detailed coding of form than for the gross form coding, but is still quite weak.
Although the overall relationship between form and classification category is not strong, the data can be partitioned in ways that show stronger links between form and classification categories. For example, ollas are almost exclusively found in the Plain category. That category, as a whole, is weakened in the strength of the relationship to form by the inclusion of bowls and jars - forms that cross cut the categories.
Cramer's test for strength of relationships between classification categories and estimated mean diameter of rims is even weaker: 0.16.
Relationships of a type to mean wall thickness (0.20) and mean rim thickness (0.24) were also quite weak.
Indeed, the only coded attribute category that shows a reasonable but still not impressively strong relationship with classification categories is the slip color and painting of the surface. Cramer's V is 0.62 for the coding of the interior surface and 0.63 for coding of the exterior surface.
These are very powerful statistics which have been applied to a collection having only weak probabalistic integrity. One might justifiably ask: "So What?" The point is that this gives a quantified expression to our overwhelming impression that slipping and decoration are the most important attributes in delineating classification categories. We don't
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want to claim too much for the meaning of the statistics, however.
Summary
In this chapter we have reviewed existing classification systems and looked at some of the problems associated with classification. By partitioning the San Dieguito ceramic data in various ways, some of the reasons for the classification problems have become evident. It is only with some understanding about the nature of the ceramic universe that the discrete data sets from the site can be placed In
perspective for comparative purposes.
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