Charles Koenig

A Reassessment of Red Linear Pictographs in the Lower Pecos Canyonlands of Texas

Abstract Red Linear is one of four presently defined prehistoric pictograph styles in the Lower Pecos Canyonlands of southwest Texas and Coahuila, Mexico. Based on interpretation of images and two experimental radiocarbon dates, the style was presumed to have been brought into the region by intrusive bison hunters around 1280 B.P. This would place production of Red Linear after the large, polychromatic Pecos River style paintings (4200–2750 B.P.). However, during a recent rock art recording project we identified Red Linear overlain by presumed older Pecos River style. This prompted our re-examination of Red Linear through analysis of 444 figures from 12 sites. We produced a list of diagnostic attributes for Red Linear and documented stratigraphie relationships through macro- and microscopic field analysis. We identified 38 examples of Red Linear under Pecos River figures, thus inverting the relative chronology for the two styles and forcing a reconsideration of previous assumptions regarding the culture that produced the art. This paper demonstrates the potential afforded by analysis of rock art assemblages to reveal inter- and intrasite patterning of attributes and provide insight into relative chronologies. Further, it cautions against the use of variation in artistic style as a marker for ethnicity.

Beyond the Square Hole

ABSTRACT The accurate and precise collection of three-dimensional (3D) context and provenience data is of critical importance for archaeologists. Traditional square-hole methods are being augmented by new digital techniques to increase the accuracy and precision with which 3D data are collected. Structure from Motion (SfM) photogrammetry is an emerging digital technique that is becoming more widespread for collecting 3D data of archaeological sites and features. We are using handheld digital cameras and ground-based SfM to record accurate and precise 3D context and provenience data at the scale of the excavation unit and profile during rockshelter excavations in the Lower Pecos Canyonlands of Texas. By combining SfM with traditional excavation methods, we collect 3D data on excavation units, layers, features, and profiles without excavating in grid-bound square units. SfM provides a straightforward and flexible method to excavate based on the stratigraphy and logistical pragmatics, which further aids in assigning precise context and provenience to recovered artifacts and samples. This article describes how ground-based SfM serves as a basic recording tool during excavation and shows that, by applying ground-based SfM methods to excavation, archaeologists can collect more, and more accurate, data than with traditional square-hole methods. La colección exacta y precisa del contexto y de los datos de procedencia en tres dimensiones (3D) de objetos y rasgos es de importancia crítica para la arqueología. Los métodos tradicionales a base de unidades cuadradas están siendo aumentados por nuevas técnicas digitales que tienen el objetivo de mejorar la exactitud y la precisión con las que se recogen los datos en 3D. La fotogrametría de estructura a partir del movimiento (Structure from Motion; SfM) es una técnica digital emergente que está cada vez más generalizada para recoger datos en 3D de sitios y rasgos arqueológicos. Utilizamos cámaras digitales portátiles con SfM terrestre para registrar los datos en 3D exactos y precisos de contexto y procedencia a la escala de la unidad de excavación y del perfil durante las excavaciones de abrigos rocosos en los cañones del Lower Pecos, Texas. Mediante la combinación de SfM con los métodos de excavación tradicionales, recogemos los datos en 3D de unidades de excavación, capas, rasgos y perfiles sin excavar en unidades limitadas por una cuadricula tradicional. La SfM proporciona un método sencillo y flexible para excavar basado en la estratigrafía y las consideraciones prácticas, lo que ayuda aún más la asignación de contexto preciso y procedencia a los materiales culturales y muestras recuperados. En este artículo se describe como la SfM terrestre sirve como una herramienta básica de grabación durante la excavación, y como por medio de la aplicación de métodos de SfM terrestre a la excavación, los arqueólogos pueden recoger datos más abundantes, y más precisos, de lo que se puede recoger con los métodos tradicionales usando las unidades de excavación cuadradas.

Response to Comments by Harrison

Abstract In our article “A Reexamination of Red Linear Style in the Lower Pecos Canyonlands of Texas,” we presented the results of an analysis of 444 Red Linear style pictographs from 12 sites in the region. Using this greatly expanded data set, we produced a list of diagnostic attributes for the style and documented stratigraphie relationships among pictographs through macro- and microscopic field analysis. We identified 38 examples of Red Linear under Pecos River style, a style previously assumed to be older than Red Linear. No Red Linear figures were identified superimposing Pecos River style. These results were verified by an independent group of archaeologists and chemists engaged in the analysis of Lower Pecos rock art. We concluded that Red Linear style is either older than or contemporaneous with Pecos River style. In Harrison’s comments, he argues that our methods were faulty and the data inadequate to support our conclusions. We address a few of Harrison’s critiques in our response; however, a more careful reading of the original article and supplemental materials is advised.