PRELIMINARY RESULTS OF A REPLICATNE STUDY: METATE RE-ROUGHENING, PECKING, OR POUNDING? Dawn M. Reid and Mari A. Pritchard-Parker Department of Anthropology University of California Riverside, CA 92521 ABSTRACT This paper discusses the results of a replicative study on the roughening of milling equipment, specifically metates. The intent of the replication was to ascertain ifdiffering results were achieved when various percussor types were used to re-roughen a metate-like surface. Hammerstones prepared by flaking and unmodified cobbles were utilized. The results obtained in the replication were then compared with archaeological specimens in an attempt to determine more information as to the manufacturing and use behaviors associated with milling equipment. INTRODUCTION ment would be most efficiently accom­ plished with tools of different shapes and Stone metates or grinding stones have sizes, depending upon how much mass one long been a primary food processing tool for is trying to remove and where that mass is many agricultural as well as hunting and located. Where manufacture seeks to re­ gathering societies. Use of these imple­ move a relatively large amount ofmass, re­ ments to reduce both plant and animal ma­ roughening seeks to merely mar the grind­ terial has been well documented. When a ing surface to such a degree that it becomes metate is used in conjunction with a mano useful again. Identifying potential differ­ to grind foodstuffs, sharp edges are sheared ences in the types of tools used in the manu­ off ofthe metate surface and residues from facture and maintenance ofmilling imple­ the material being ground are deposited. ments will contribute to our overall under­ This process results in the metate surface standing ofartifact distributions and their becoming increasingly smooth, ineffectual, associated behaviors. For example, explana­ and in need ofmaintenance. Rejuvenation tions may be advanced for hammerstones ofthe metate can be achieved through re­ found in behaviorally significant numbers roughening ofthe grinding surface thus ex­ near completed metates or milling activity tending its usefulness. areas. Additionally, use wear patterns on hammerstones will vary depending upon the Replicative studies involving the manu­ way in which they were used. A knapping facture ofmilling equipment (Pritchard­ hammer will reflect glancing rather than di­ Parker 1991) sparked discussions concern­ rect action fracture whereas a tool used to ing possible differences in the type ofham­ roughen a grinding surface should reflect a mer tool used to manufacture metates ver­ definite fracture pattern, delineating it from sus those used to maintain the milling sur­ other hammer tools. The resultant debitage face through re-roughening. Both angular­ from such an activity, which may often ap­ edged hammers and unmodified cobbles pear anomalous, may also be diagnostic of have been used in the replicative manufac­ the metate re-roughening process. ture ofmetates (Pritchard-Parker 1991; Schneider et al. 1992). However, it may be Ethnographic literature contains vague possible that the differing tasks ofmanufac­ references to "pecking" stones used in the turing and re-roughening ofmilling equip­ re-roughening process (Mohr 1954; Lister Proceedings of the Society for California Archaeology, 1993, Vol. 6, pp. 199-206. Copyright@1993 by the Society for California Archaeology. 1965; Huckell1986; and others). Pecking, as width from 25.5 em to 30.5 cm. defmed by Turner (1963), is performed with a "sharpened hammerstone". The few de­ Three hammerstones were used in the scriptions of these stones allude to a modi­ Phase 1 experiment (hammerstones 1, 2, fied cobble with sharp edges or points, a and 3 in Table 1). All 3 hammerstones were sharp broken stone, or a prepared core. No quartzite cobbles that had one end flaked to references describing the use of blunt ham­ form an angular-edged hammer, and the merstones for re-roughening were found. other end left unmodified (rounded). Using However, one account of excavations at the 2 ends of a single cobble as different Mesa Verde included pictures ofrecovered tools helped to control for the consistency of "pecking" stones (O'Bryan 1950) that appear the quartzite among the hammerstones. to be unmodified cobbles with the cortex The weights of the hammerstones ranged and naturally-occurring rounded edges in­ from 566.9 g to 577.4 g. This weight range tact. For this reason, it seemed appropriate was intended to approximate the average to suggest that the term "pounding" be weight ofarchaeological specimens as calcu­ adopted (Jeanne Binning, personal commu­ lated from the mean weight of a collection of nication, 1991) to describe the use ofblunt 216 hammerstones recovered from a site, or unmodified hammerstones. While it has ORA-1070, in Orange County (Mike Macko, been suggested that the rounded or blunt personal communication, 1992). ends of manos could have been used to roughen metate grinding surfaces by Riddell (1960) and others, no replicative work that Table 1 we know of has addressed this issue. Hammer Tool Attribute Summary The goal of this experimental project was to evaluate the results obtained with original Final Used on both angular-edged and naturally rounded # Material Weight Weight Shape* Slab or blunt hammerstones when each was used to roughen a simulated metate surface. We 1 Quartzite 566.9 9 482.0 9 combo Granite focused on the following question: Would 2 Quartzite 573.5 9 403.2 9 combo Granite rounded-edged hammers be as effective as 3 Quartzite 577.4 9 354.3 9 combo Basalt angular-edged hammers in the metate re­ 4 Rhyolite 763.6 9 481.8 9 angular Basalt & roughening process? We observed the mor­ Granite phology of the dents (Turner 1963) or indi­ 5 Quartzite 2365.6 9 1543.6 9 unmod Basalt vidual pits resulting from the blows admin­ 6 Quartzite 1071.4 9 1071.4 9 angular Weathered istered with the different tool shapes. In Granite building upon the results ofthe initial phase 7 Quartzite 1094.1 9 1072.2 9 unmod Weathered ofthis study, additional variables were con­ Granite sidered, including weight of the hammer­ stone and material of both the hammer and *combo=coMbination; unmod=unmodified the grinding surface. PHASED EXPERIMENTS In conducting the experiment, each of the slabs was divided into halves. Hammer­ Phase 1 stones 1 and 2 were used on the granite Methods. In order to control the initial sur­ slabs, with half of each slab being "pecked" face characteristics of the simulated met­ with the angular-edged ends of the ham­ ates, 2 slabs of granite and one slab of basalt, merstones, and the other half of each gran­ obtained from a local monument works, ite slab being "pounded" with the rounded, were used. All of the slabs had smooth sur­ unmodified, ends ofthe hammerstones. faces cut with a rock saw. The smooth, uni­ Hammerstone 3 was used in the same man­ form surfaces allowed the effects of each ner on the basalt slab. The ends of each hammer type to be isolated. The slabs hammerstone were to be used to strike the ranged in length from 37 cm to 51 em and in simulated metate surface 150 times. In or­ 200 der to evaluate use*attrition of the hammer* Phase 2 stones under conditions ofpecking and Due to the rates of tool weight loss pounding, each hammerstone of known caused by use-attrition during Phase 1 (Fig­ weight was fIrst used for pecking, then the ure 1, hammerstones 1, 2 & 3), it was con­ resulting debitage was weighed. Each cluded that the original weights of the ex­ hammerstone was then used for pounding, perimental hammerstones may have been and the newly produced debitage was too low to replicate actual tools used prehis­ weighed. A fmal weight of each hammer­ torically. Considering the possibility that a stone was also recorded. majority ofthe hammerstones recovered ar­ chaeologically may have been expended Results. The dents produced in the surfaces tools, the average weight ofhammerstones of the basalt and granite slabs by the angu­ during their use-life may have been signifI­ lar-edged hammerstones were irregularly cantly greater than that recorded for the ar­ shaped and had some depth, whereas the chaeological specimens. Itwas also rec­ blows administered with the unmodifIed ognized that the material of the hammer­ (rounded) tools resulted in elongated marks stones used in Phase 1 (quartzite) may ac­ on the slabs that infrequently broke the sur­ count for some degree of the use-attrition face sufficiently to create a dent. The only experienced. It was also desirable to know if difference in dent morphology between the hammerstone weight and material account­ basalt slab and the granite slabs was the ed for some degree ofthe use-attrition ex­ somewhat greater depth of dents produced perienced and if these factors had any effect in the granite slabs. on the morphology of dents produced in the struck surface. The damage to the angular-edged ham­ mers themselves was reflected in crushed Methods. To test the effect of hammerstone edges and step fractures. The rounded­ weight and material on hammers tone use­ edged hammerstones tended to develop bat­ attrition and dent morphology, 2 hammer­ tered bifacial edges and took on a chopper­ stones of greater weights were used, one of like appearance. which was made of rhyolite. The rhyolite cobble was flaked to form an angular-edged An extreme amount of tool loss and early hammerstone weighing 763.6 g (#4 in Table tool failure was experienced with the ham­ 1), and a quartzite cobble weighing 2365.6 g merstones, particularly with the initially was left unmodifIed (rounded; #5 in Table unmodifIed (rounded) tool edges (see Figure 1). The rhyolite tool was used to strike both 1, hammerstones 1, 2, and 3). 150 blows the granite and basalt slabs, and the quartz­ were administered with the angular ends of ite tool was used to strike the basalt slab.