Scrapers

Unifacially shaped or use-damaged stone tools, generally termed scrapers, frequently constitute the most abundant class of lithic artifact, apart from debitage, in the prehistoric assemblages of San Diego County. Perhaps no other prehistoric lithic tool class in the region has been the subject of such extreme typological differentiation. Explicitly or implicitly, scraper tool types have been related to distinctions in chronology, cultural tradition, activity, and tool use cycle. Inconsistencies and ambiguities in the ways scraper types have been defined may have affected many of the descriptions and interpretations of local prehistoric tool assemblages.

Elaborate scraper typologies have been employed by some San Diego archaeologists, notably by Malcolm J. Rogers (1929, 1939, 1966); by D. L. True, Claude N. Warren, and their collaborators (True 1966, 1970, 1980; True et al. 1974, 1991; Warren 1964, 1966; Warren and True 1961; Warren et al. 1961); and by some later archaeologists, including Ronald V. May (1975), Russell L. Kaldenberg (1982), and Dennis H. O’Neil (1982). A range of attributes have been suggested as significant in classifying these artifacts:

• Shaping vs. Use Damage. Tools that show evidence of purposeful shaping on their working edges have been distinguished from cores or flakes that show only modification resulting from use. The distinction between shaping and use damage seems to have been based most commonly on the size of the flake scars produced. Unresolved problems exist in trying to distinguish the modifications made to shape working edges or produced during use from modifications that resulted from preparing cores for flake removal or from accidental postdepositional damage. 
• Tool Size. The sizes of tools have been characterized on the basis of their weight or their maximum dimension. For example, Kaldenberg categorized “thumbnail scrapers (micro-scrapers)” as less than 5 centimeters in length. Rogers (1929) seems to have used size as a primary criterion in distinguishing scraper planes from scrapers; he also distinguished “large” and “small” planes (Rogers 1966). True and his collaborators distinguished scraper planes from domed scrapers primarily on the basis of the larger size of the former. Roy A. Salls (1985) apparently distinguished scraper planes from scrapers on the basis of the steeper edge angle of the latter; however, in experiments using replicated tools to pulp yucca leaves for fiber, he noted that the scraper planes were more efficient than the scrapers because of the former’s “size and weight” (Salls 1985:103).