Chapter 10 The Clay SourCeS of The TheaTer PoTTery WorkShoP: a PeTrograPhiC STudy anaT Cohen-Weinberger and yuval goren BaCkground The study of the ceramic finds from the theater pottery workshop has the potential of contributing to our understanding of the pottery technology and production processes used during the Umayyad period at Bet She’an. Generally, the collection and analysis of wasters (usually vessels warped to a degree that renders them totally unusable) and ceramic samples from a production site are valuable to the ceramic petrologist for characterizing the fabrics from a single workshop. Kiln studies, in which petrography is an essential component, can be particularly valuable in refining our knowledge of the varieties and range of fabrics used in the production process, as well as furnishing technical details. Determining the raw material used in a specific workshop enhances our understanding of the distribution of its products in petrographically studied assemblages from other sites. A detailed survey of ethnographic data concerning present-day traditional potters indicates that the exploitable territory of clay and temper is usually limited by the expenditure of time and distance to the raw material sources. Based on numerous round-the- world reports on clay exploitation by potters and dozens of cases regarding temper use, Arnold (1985:32–60) concluded that in most cases, the exploitable territory does not extend beyond a range of 10 km from the potter’s location (Arnold 1985:49, Fig. 2.5). Thus, drawing a circle with a radius of 10 km around any given site can establish its most likely exploitable territory for clay and temper resources. Within this circle, possible clay and temper types can be determined in order to predict the Clay-Temper-Factor (CTF) of the site, namely, the quality and quantity of possible clay and temper sources in the exploitation territory (Goren, Finkelstein and Na‘aman 2004:8). The Bet She’an Valley is rich in water sources and clay deposits, making it suitable for pottery production. The abundant clay and temper sources in this area give it a high CTF index, which means that the Bet She’an potters had a choice between various raw materials based on different considerations that will be assessed here. Several petrographic studies of pottery of various periods from Bet She’an and adjacent sites have already been conducted and the local raw materials used during these periods at various sites are well known (Goren 1991b; McGovern et al. 1993:82–87; Cohen-Weinberger 1997, 1998, 2009; Killebrew 1998; Mazar, Ziv-Esudri and Cohen-Weinberger 2000). Method Ninety-one petrographic thin sections of selected vessels and sherds found in the various kilns and waste areas were used for the present petrographic analysis (see Table 10.2). 1 Sherds and vessels that were petrographically analysed are marked with their petrographic group in the ceramic figures (Chapter 11). In addition to these sherds and vessels, two contiguous samples were taken from the wall of Kiln 5 (Fig. 10.1h; see Fig. 2.63), cut through the thickness of the kiln wall’s clay inner lining, representing a traverse from the inner face of the lining (which was exposed to the fire) up to its outer face. Another sample was taken from a clay pile in the clay supply storage area adjoining Kiln 5 in the western courtyard (see Fig. 2.13), which was probably used as raw material in this workshop. 2 Samples of potential raw materials had been collected in the field previously by Cohen-Weinberger (1997; 1998), as well as during the course of this study, and served for comparative analysis. These samples include a clayey layer containing mainly travertine fragments, exposed near the Bet She’an Severan theater, and clay from the Hatira, Netufa, and Tammun Formations in Wadi el-Malikh. These samples were moistened and shaped into small briquettes. Two briquettes were made from each hand sample; after drying, one specimen was fired in a