Rockshelters, Rockart and Grinding Activity: A Preliminary Assessment of Relationships in Picket Wire Canyonlands, Comanche National Grasslands

The Pinon Canyon Maneuver Site (PCMS) has undergone extensive inventory over the last two decades. Although several thousand Native American sites have been recorded within the PCMS boundaries there are 662 that can be used for this analysis. In these cases, the observations were recorded in a consistent fashion. This limited database contains both nominal and categorical variables or fields. Within this data set there are 171 sites that possess observations with at least one of the following variables: rochshel, rockwarc, groundstone, rockart, or architecture. We asked one fundamental question of the PCMS data set: To what extent is the presence of prehistoric grinding or milling activity, rock-art, and architectural remains spatially associated with the human use of a rockshelter? Analysis suggests that rockshelters, both modified and unmodified, show a weak association with evidence of grinding activities (Table 1). The presence of rock art is much less associated with modified rockshelters and devoid of any demonstrable association with unmodified rockshelters. Log-linear analysis (binary logit SYSTAT v.10.2) indicates however that the presence of grinding activities is the best predictor of rockshelter occupation (Table 2). That is, controlling for rock art, the probability of groundstone being present at an unmodified rockshelter is 16.5 times greater than evidence of these remains being absent. Similarly, at modified rockshelters, the probability of groundstone being present at the site is 5.75 times greater than its presence not being observed.皮尼峡谷演习场地（Pinon Canyon Maneuver Site，PCMS）在过去二十年间开展了全面的考古清查工作。尽管在PCMS辖区范围内已记录有数千处美洲原住民遗址，但本次分析仅选取其中662处开展研究。该批次遗址的观测数据均以统一标准采集与记录。本精简数据库包含定名变量与分类变量两类字段。数据集内共有171处遗址具备至少一项以下观测变量：rochshel、rockwarc、groundstone、rockart或architecture遗存。 我们针对PCMS数据集提出了一项核心研究问题：史前磨制或研磨活动遗存、岩画及建筑遗存的空间分布，是否与人类对岩棚的使用存在关联？关联程度又如何？分析结果显示，无论经改造与否的岩棚，其与磨制活动遗存的关联度均较弱（见表1）。岩画遗存与经改造岩棚的关联度更低，且与未经改造岩棚无任何可证实的空间关联。对数线性分析（采用SYSTAT v.10.2软件完成二元逻辑回归分析）结果表明，磨制活动遗存的存在是预测岩棚被人类占用的最佳指标（见表2）。具体而言，在控制岩画遗存变量的前提下，未经改造岩棚中存在磨制石器遗存的概率，是未发现该遗存的16.5倍；同理，经改造岩棚中存在磨制石器遗存的概率，是未观测到该遗存的5.75倍。