On the Significance of Additional Radiocarbon Dates from Bonfire Shelter, Texas

Two hitherto unreported dates from charcoal sam ples associated with remains attributed to a Paleo-Indian bison kill at this site are provided. These dates further substantiate a minimal antiquity of ca. 10,000 years for the deposit and, by inference, give evidence of the use of a "bison jump" technique of hunting at this early time period. Definitional problems, differing views on the antiquity, basic comparability of cited examples, and temporal continuity of this mode of mass killing are briefly discussed. Some suggestions are made as to the cultural implications made probable by acceptance of an early date for this practice. Archaeological excavations carried out in 1963-64 at Bonfire Shelter, Val Verde County, Texas, by the Texas Archeological Salvage Pro ject under contract with the National Park Service revealed two extensive and stratigraph ically discrete deposits of bison bone. The position of these deposits with respect to an overhanging cliff and the surrounding landscape, evidence of on-the-spot butchering, and the clear association of lithic artifacts led to the conclu sion that the bone beds resulted from planned "drives" which had taken place in Paleo-Indian and late Archaic times (Dibble and Lorrain 1968). During both periods, it is apparent that herds were driven off the rim of the entrenched canyon and processed near or at the point of impact under and fronting the overhang. The lowest of these deposits, Bone Bed 2, consisted of the remains of an estimated 120 animals of an extinct species (Bison antiquus or occidentalis) in direct association with a small collection of projectile points classified as Plainview and "Plainview-like," plus a single Folsom. A general lack of skeletal articulation, the rareness of certain elements (e.g., horn cores), and deliberate crushing of most of the marrow-yielding bones indicated heavy and systematic utilization. Bone Bed 3, a much larger bison bone accumulation dating from about 650 750 B.C. (Dibble and Lorrain 1968:51), will not be specifically dis cussed here. Bone Bed 2 was visually separable, over much of its extent, into three superimposed compon ents. These tightly bedded layerings were inter preted as representing the remains of kills separ ated by relatively short time intervals. An esti mate of the age of Bone Bed 2 has been based primarily on a single C14 date on charcoal collected from a hearth stratigraphically equat able with the uppermost component. This date, 10,230 ? 160 years B.P. (8,280 B.C.), is reported by Pearson, et al. (1965). Recently, two addi tional samples removed from the same hearth have been dated by The Radiocarbon Dating Laboratory, The University of Texas at Austin, with the following results (Valastro and Davis, in press): Sample No. Tx 657 9,920 ? 150 yrs. B.P. (7,970 B.C.) Tx 658 10,100 ? 300 yrs. B.P. (8,150 B.C.) The three dates are impressively grouped; all overlap within one standard deviation and pro vide an average date of 10,080 ? 130 yrs. B.P. (8,130 B.C.). These calculations statistically firm the radiocarbon age of the latest of a sequence of events which led to the accumulation of Bone Bed 2. This additional dating assumes anthropologi cal significance in that it serves to substantiate the antiquity of an effective exploitative tech nique specifically the "bison jump". In a minimal definition favored by this writer, the bison jump involves a purposeful and directed stampeding of animals over a cliff or a sudden, but less abrupt, declivity of sufficient height and