Forbidden Archeology: The Hidden History of the Human Race

Among the key attributes that Patterson suggested were the presence of clearly marked striking platforms (especially those modified for better flaking), multiple examples of tool types, platform angle measurements, the presence of bulbs of percussion and associated ripple lines, and the geological context. Other attributes that might be considered are the presence of regular retouching, sharp edges (nature tends to produce rounded edges), and signs of parallel flake removal. This balanced approach is typical of the methodology applied by the original discoverers of the stone tool industries discussed in the preceding pages.

Let us now consider in greater detail some of the key attributes identified by Leland W. Patterson and others. Patterson considered the bulb of percussion to be the single most important identifying factor. With regard to Calico, Patterson and his coauthors stated: “Of the 3,336 flakes from five Calico units, 26.1% had force bulbs and were classified as diagnostic flakes. In the experimental knapping project, using hard percussion, 24.3% of the 473 flakes possessed force bulbs and were classified as diagnostic flakes. By comparison, flakes produced by mechanical crushing (pressure force) usually have a very low percentage of distinguishable force bulbs, as shown by samples of flakes from mechanical gravel crushers” (L. Patterson et al. 1987, p. 95).

Patterson (1983, p. 300) also pointed out that percussive fracturing tends to produce prominent ripple lines radiating from the impact point, whereas pressure fracturing produces finer ripple lines. In addition, percussion fracturing can result in the presence of eraillures, small chips removed from the ventral surface of the force bulbs.

Patterson stressed the bulb of percussion, force ripples, and eraillures as very important in making an identification because stone flaking by humans almost always involves percussive techniques, whereas naturally broken stone is generally the result of pressure flaking. Patterson and his coauthors stated: “To date there is no documented situation where natural forces have produced large concentrations of percussion made flakes” ( L. Patterson et al. 1987, p. 96).

In some controversial cases, Patterson has suggested that “the geological context of a lithic collection becomes important in determining if nature would have had the probable capability of fracturing rock, especially in a percussive manner” (L. Patterson 1983, p. 299). He added: “The only published manner that nature can do much percussive fracturing is under high-energy, ocean-beach storm conditions. . . . viscous liquids and slurries inhibit high-velocity percussive interactions of rocks. Pressure fracturing gives different lithic attributes than the percussive-type flaking used by early man. . . . Another condition in which nature can break rock is when flint nodules are held in a secure limestone matrix and there is a shift in the mass. Here, it is common to see shear fractures that have none of the key attributes of percussive fracture patterns” (L. Patterson 1983, p. 299). Here we see that Patterson, in common with the original proponents of many early stone tool industries, believed that it is possible to clearly distinguish natural pressure fracturing from that caused by intentional percussion flaking techniques.

In regard to tool type analysis and distribution patterns, Patterson commented: “Even if nature can produce lithic objects resembling simple man-made items, nature is not likely to do this often. Therefore, the frequency of occurrence at a given location of specimens with similar morphologies is important in demonstrating probable manufacturing patterns. Production of numerous lithic specimens with consistent morphology is certainly not a habit of nature. Quantitative data on amounts of each specimen type should therefore always be presented” (L. Patterson 1983, p. 298).