sign in sign up
<<
Home , Lithic technology, Middle Awash, Sally McBrearty, Sangoan, Uniface

367

raw materials from increasingly distant sources, geographic Reports patterning in styles, a broadened dietary base, use of sophisticated hunting techniques, and early evidence for sym- bolic representation (see McBrearty and Brooks 2000; Hen- “Early” Middle shilwood and Marean 2003 for recent reviews). These behav- of the Kapthurin Formation ioral innovations are significant because of their broad temporal and geographic coincidence with the origin of (Kenya) sapiens as this is currently understood (Howell 1999; Lahr Christian A. Tryon and Foley 1998; McBrearty and Brooks 2000; McDougall, Brown, and Fleagle 2005; Tishkoff and Williams 2002; White Department of Anthropology, George Washington et al. 2003). The relations and timing of these biological and University, 2110 G St. NW, Washington, DC 20560-0112, behavioral changes are therefore a central issue for the origin U.S.A. ([email protected]). 25 X 05 of our species. Unfortunately, the Acheulian-MSA transition is poorly un- The production of Levallois flakes is considered a hallmark derstood, in part because most MSA sites are Later of many (MSA) sites, but this aspect of in age (Klein 1999; McBrearty and Brooks 2000), substantially African Pleistocene hominin technology remains poorly doc- more recent than the youngest Acheulian sites. To call atten- umented relative to that from adjacent regions. The site of tion to this bias in the available evidence, McBrearty and Koimilot, from the Kapthurin Formation of Kenya, preserves Tryon (2005) identify an “early” Middle Stone Age that in- stratified artifact assemblages that show use of multiple Le- cludes sites that date to the Middle Pleistocene, that is, 1 vallois methods to produce flakes of varied shapes and sizes, 130,000 years ago, and are therefore more relevant to un- comparable to that described from Levantine and European derstanding the transition. The rarity of such sites potentially Middle sites. Koimilot has an age of ∼200,000 years exaggerates behavioral contrasts between Acheulian and MSA on the basis of geochemical correlation with dated volcanic hominins and confounds our attempts at understanding the tephra and therefore joins a small but growing number of precise relationship between the technological changes initi- “early” MSA sites which antedate the last interglacial ated at the end of the Acheulian and biological changes within (∼130,000) years ago and provide the most relevant com- the Homo lineage. My goal in this paper, complementing parisons for understanding the end of the Acheulian. The previous studies of the complex record of the Acheulian-MSA Kapthurin Formation archaeological sequence suggests that transition in the Kapthurin Formation of Kenya (Tryon and it is the diversification of Levallois technology rather than its McBrearty 2002, n.d.), is to describe the methods of flake production at the early MSA site of Koimilot. I focus on flake origin that characterizes early MSA assemblages. MSA Lev- production because this approach has been shown to be an allois technology may have developed from local Acheulian effective means of isolating local trajectories of technological antecedents. change in MSA artifact industries, which frequently lack the retouched necessary for most typological analyses (Wurz The end of the Acheulian and the beginning of the Middle 2002). I emphasize Levallois flakes and cores because they are Stone Age (MSA) reflect the most important later Middle considered a hallmark of many MSA industries (Clark 1988). Pleistocene archaeological event in Africa (Clark 1999; However, Levallois technology has not been the subject of the McBrearty 2001; Tryon and McBrearty 2002). Acheulian sites same level of detailed study at African sites as at European are typologically defined by the presence of large cutting tools and Levantine ones (but see Pleurdeau (handaxes, cleavers, and ). These are replaced at MSA 2003; Van Peer 1998), where there is demonstrable geographic sites by smaller stone and bone points, presumably hafted as and temporal patterning in the production methods and mor- composite tools, and more frequent use of various Levallois phologies of Levallois flakes, blades, and points (Bar-Yosef methods of flake production. These shifts in artifact type and 2000; Boe¨da 1994; Inizan et al. 1999; Tuffreau 1995). Data ∼ technology, which first occurred 250,000–300,000 years ago, from Koimilot are used to construct a framework for changes underlie more profound changes. The end of the Acheulian in that can be used to address other later marks the end of a highly successful, relatively stable hominin Middle Pleistocene hominin adaptations. behavioral adaptation that persisted for over a million years throughout much of the Old World (e.g., Petraglia and Ko- Koimilot Age and Context risettar 1998). MSA sites record hominin expansion into new habitats, increased foraging range, selection for finer-grained Koimilot (GnJh-74) is one of numerous Acheulian and Mid- dle Stone Age sites from the Kapthurin Formation, sediments ᭧ 2006 by The Wenner-Gren Foundation for Anthropological Research. of which crop out west of Lake Baringo, in the central Rift All rights reserved 0011-3204/2006/4702-0006$10.00 Valley of Kenya (fig. 1). The Kapthurin Formation also pre- 368 Current Anthropology Volume 47, Number 2, April 2006

Fig. 1. Inset map (A) and detail (B), showing location of Koimilot and other Kapthurin Formation sites discussed in the text, and (C) schematic stratigraphic section of Koimilot. serves a diverse fauna that includes hominin mandibles and lake shoreline. The vicinity of the site during these occupations postcrania recently attributed to Homo rhodesiensis,aswellas probably differed little from the area west of Lake Baringo today. the first fossils, in a sequence dated by multiple The Locus 1 excavated assemblage consists of 3,782 artifacts 40Ar/39Ar age determinations to ∼250,000–550,000 years ago from a single ∼10-cm-thick layer exposed in a 38-m2 excava- (Deino and McBrearty 2002; McBrearty 1999; McBrearty and tion. Artifacts occur immediately beneath portions of a weakly Brooks 2000; McBrearty and Jablonski 2005; Tallon 1976, expressed paleosol that developed on poorly sorted, sheetflood- 1978). deposited sands. In addition, 251 artifacts were collected from Excavations at Koimilot in 2001–2 revealed two spatially the surface at Locus 1, with some surface-recovered artifacts segregated, stratified archaeological components (Tryon 2002, refitting with excavated material. Lithic clusters of dif- 2003). Both Locus 1 and the younger Locus 2 overlie a 120- ferent raw-material types, multiple refitting artifact sets, and a m-thick succession of volcaniclastic, alluvial fan, and possibly lack of evidence for size-sorting suggest a high degree of spatial lacustrine sediments of the Bedded Tuff Member (fig. 1). Ar- integrity, with archaeological deposits interpreted as the result tifacts occur in sediments that represent different facies of a of a succession of brief occupations (Tryon 2003). At Locus 2, distal-alluvial-fan depositional environment near a fluctuating a 26-m2 excavation produced 310 artifacts, and 33 artifacts were 369 found at the surface. Excavated artifacts occur in coarse sands Table 1. Excavated Artifacts from Koimilot Locus 1 and and sand-supported pebble conglomerates, apparently con- Locus 2, following a Nested Classification Scheme Based on forming to relict channel margins within a palaeotopographic Isaac, Harris, and Kroll (1997) low. The assemblage has been winnowed, but the presence of refitting debitage sets and the fresh state of the artifacts suggests Locus 1 (n p 1,412) Locus 2 (n p 310) only limited transport. Detached pieces Electron microprobe geochemical analysis of the Koimilot Flakes 235 65 tephra allows integration into the established succession of Flake fragments 1,125 236 Bedded Tuff Member volcaniclastic deposits (Tryon and Flaked pieces ∗ McBrearty 2002). The results, described in detail elsewhere Casual cores 12 0 (Tryon 2003; Tryon and McBrearty n.d.), show that both Platform cores 2 2 Radial cores 10 4 archaeological loci at Koimilot overlie tephra that are geo- Misc. core fragments 8 3 chemical correlates of upper basaltic portions of the Bedded Shaped tools 1 0 Tuff Member. All other known sites occur beneath the upper Pounded pieces basaltic portions of the sequence. Koimilot is therefore the 4 0 youngest excavated site from the Kapthurin Formation, ex- Unmodified stones 15 NC tending the existing archaeological succession. The “Koimilot Note: The Locus 1 total does not include 2,370 sieve-finds ! 3cmin Tuff” is a locally distinct marker bed that may allow future maximum dimension. NC p not collected; ∗includes 9 split cobble frag- correlation with other Pleistocene depositional basins. Its ments. Totals are revised from Tryon (2003) and include a larger sample. grain size and chemical composition suggest derivation from a distant source. The “Koimilot Plant Tuff” that stratigraph- parable to lavas that crop out ∼15–20 km upstream from the ically lies between the Locus 1 and Locus 2 excavations con- site in the Tugen Hills (e.g., Chapman 1971; Tryon 2003). tains basaltic glass shards geochemically comparable to those The groundmass grain size of some of the archaeological ma- intermixed within both trachytic deposits 40Ar/39Ar-dated to terial overlaps with that of some varieties of or flint and years ago by Deino suggests deliberate selection for fine-grained, homogeneous 2,000 ע and 235,000 12,000 ע 28,400 and McBrearty (2002). This suggests its eruption and depo- raw material. sition immediately prior to or concurrent with the later tra- The split cobbles and casual cores (the latter defined by ! chytic eruptive phases of the Bedded Tuff Member (Tryon 5 flake removals [after Isaac 1977]) demonstrate initial phases 2003; Tryon and McBrearty n.d.). On this basis, an age of of cobble testing and discard at Locus 1. Other evidence sug- ∼250,000 years ago is estimated for Koimilot, pending con- gests preservation of extended episodes of some of firmation by future isotopic dating. Minimum age estimation these locally procured cobbles. This includes the presence of is rendered difficult by a lack of datable overlying sediments. hammerstones and cortical “first flakes” or entames (Tixier However, the termination of Kapthurin Formation sedimen- 1974) and the retention of typical stream cobble cortex on tation and the onset of the current erosional regime is defined flakes and flake fragments in proportions comparable to ex- by a major faulting episode. Recent U-series age estimates of perimental artifact replications (22.61%) (e.g., Bradley and ∼198,000–345,000 years ago on thermal silica in-filled cracks Sampson 1986; Geneste 1985, 170–270). within lavas related to this faulting are consistent with a later I divide the remainder of the cores into two broad cate- Middle Pleistocene age for Koimilot (Le Gall et al. 2000; Tallon gories. Platform cores show flake removals from single or 1976). multiple striking platforms, often with little or no preparation, with steep flake-removal angles that may approach 90Њ (Con- Lithic Technology at Koimilot et al. 2004 Mehlman 1989). Radial or centripetal cores (defined after Kuhn 1995), are typically oval in plan view, The artifacts 13 cm in maximum dimension from the Locus with invasive flake removals directed toward the center from 1 excavation include complete flakes, flake fragments includ- all or part of the circumference of the piece; striking-platform ing angular debris, cores, core fragments, and split cobble preparation is variable. Radial cores may have one or two fragments, hammerstones, and a single shaped implement flake removal surfaces; surfaces on bifacial cores are often (table 1, fig. 2). The lithic assemblage consists of at least ten asymmetrical, typically with biconvex or biconical cross sec- lithologically distinct types of fine-grained trachyphonolitic tions. I subsume centripetally flaked Levallois cores and dis- lava with sparse phenocrysts ≤ 2 cm. Rounded ∼10–20-cm coidal cores from Koimilot as radial core subtypes (see clasts of these and other lavas occur in conglomerates that Mourre 2003), in part to simplify comparison with similar crop out within 50 m of the site. Cobble-dominated bars and cores that form a common component of many African Pleis- thalwegs in stream channels, now exposed as conglomerates, tocene assemblages (e.g., Clark 2001; Isaac 1977) but also to served as a locally available raw-material source at Koimilot. emphasize the difficulty in distinguishing from discarded Comparison of thin sections shows that both Koimilot arti- cores alone what may have been different approaches to flake facts and adjacent cobble deposits are petrographically com- production (e.g., Marks and Volkman 1987). 370 Current Anthropology Volume 47, Number 2, April 2006

Fig. 2. Artifacts from Koimilot Locus 1, including centripetally prepared Levallois cores and refitted flakes (a, c), a preferential Levallois core (b), a Levallois flake produced by the recurrent method (d), an e´clat de´bordant a dos limite´ (e), a pointed (f ), a Levallois core discarded during the initialization phase (g), and a multiplatform core from opportunistic exploitation of an irregular chunk (h). All Locus 1 artifacts are from the excavated sample, and all are of fine-grained lava. Numbers indicate order of flake removal where determinable. show the direction of flake removal and presence or absence of the negative of the bulb of percussion. Blank scars are those for which flake removal orientation is unclear.

Two platform cores from Locus 1 show opportunistic ex- whereas others likely result from a Levallois approach but ploitation of unprepared striking platforms on irregular were discarded during an early initialization phase (fig. 2, g). chunks (fig. 2, h). Radial or centripetal cores are the more Also recovered were core-trimming flakes (pseudo-Levallois numerous type. Seven of the radial cores result from appli- points or eclats de´bordants a dos limite´ [Meignen 1996]) that cation of preferential and recurrent Levallois methods (as de- preserve a portion of the former core margin along the lateral fined by Boe¨da 1994; Inizan et al. 1999; Van Peer 1992) for edges, reflecting a centripetal pattern of flaking during core the production of single or multiple Levallois methods per reduction (fig. 2, e). prepared surface, respectively (fig. 2, a–c). Such cores are Dorsal scar patterns and platform attributes from the an- distinguished by asymmetrically convex opposed flaking sur- alyzed complete flake sample support observations from cores faces, the maintenance of lateral and distal convexities on an and refitted flakes (table 2). Most flakes have either simple “upper” flaking surface opposite a cortical base, and refitting dorsal scar patterns or plain platforms not specific to any Levallois flakes with faceted platforms (fig. 2, a, c, d). Some flake production method. Relatively high proportions of flakes radial cores show a discoidal approach (see Boe¨da 1993), with subradial and radial scar patterns (29.73%) and flakes 371

Table 2. Attribute Data for In Situ Complete Flakes from different frequencies. This assemblage also has proportions of Koimilot cortical pieces (28.95%) suggesting close proximity to cobble sources. Casual cores, split cobbles, and hammerstones, how- Locus 1 Locus 2 ever, are all absent. Radial cores are the most frequent type in the small excavated sample. This sample includes a recur- n % n % rent Levallois core with a refitting flake removed to maintain Platform type the convexity of the main flake-release surface (fig. 3, h). Cortical 25 11.26 6 9.52 Complete flake attributes from Locus 2 suggest the predom- Plain 128 57.66 32 50.79 inance of centripetal flaking, with 39.68% of flakes with radial Dihedral 58 26.13 18 28.57 or subradial dorsal scars and 38.09% of flakes with dihedral Faceted 8 3.60 6 9.52 Other 3 1.35 0 0 and faceted platforms. Total 222 100.00 63 100.00 The Locus 2 assemblage differs from that of Locus 1 in Dorsal scar pattern several ways. First, one of the two platform cores has blades Cortical/plain/simple 137 61.71 31 49.21 or bladelets removed from opposed platforms (fig. 3, g). Else- Radial and subradial 66 29.73 25 39.68 where in the Kapthurin Formation, at the Leakey Handaxe Convergent 8 3.60 3 4.76 Other 11 4.95 4 6.35 Area, production is a rare but notable of the Total 222 100.00 63 100.00 local late Acheulian (Leakey et al. 1969; McBrearty 1999; Tex- ier 1996). Secondly, the most conspicuous feature of the Locus Note: Striking-platform types as defined by Inizan et al. (1999); dorsal 2 assemblage is the presence of five large (∼10 cm) elongated scar pattern categories adapted from Isaac (1977). Totals are revised from Tryon (2003) and include a larger sample. or triangular preferential Levallois flakes, two from the surface and three from the excavation (fig. 3, a–e). The dorsal scar pattern on these flakes indicates primarily unidirectional or with dihedral and faceted platforms (29.73%) are consistent convergent flaking, and their morphology is consistent with with experimentally produced flake assemblages from cen- that of Levallois points. A core collected from the surface at tripetally prepared Levallois cores (e.g., Boe¨da and Pelegrin Locality 117 (GnJh-75), ∼100 m west of Locus 2, suggests the 1979). probable means of flake production (fig. 3, f ), although no A single shaped implement was recovered from Locus 1. such cores were found during excavation of Locus 2. Flake Termed a “pointed uniface” after Villa (1983), this un- removals are primarily parallel to the long axis of the core, derlines the difficulty of a typological approach to hominin with the Levallois flaking surface shaped by the removal of behavioral variability in the African later Middle Pleistocene. elongated e´clats de´bordants (“edge-of-core flakes” [Beyries and Following the typology of Clark (2001), the pointed uniface Boe¨da 1983]), probably cortically backed, from both lateral (fig. 2, f ) could be classified as a pick with an untrimmed margins of the core. Such large flakes are not found in the base, a core-, or a unifacial handaxe with an untrimmed assemblage, nor do other complete flakes show convergent base. Alternatively, it may be an “unfinished” handaxe dis- or parallel scar patterns. The lack of large ´clatse de´bordants carded prior to completion or even a core (see Ashton, or similar flakes or cores and the absence of other flakes or McNabb, and Parfitt 1992). However, the pattern of small flake fragments of raw material similar to that of the pieces flake removals at the tip and the bilateral symmetry of the illustrated in figure 3 (a, c) suggest that the large elongated piece (after Inizan et al. 1999), visible in cross section (fig. 2, Levallois flakes were manufactured elsewhere and transported f ), suggest deliberate shaping. The size (∼15 cm) and weight to Locus 2 complete. No deliberately shaped or retouched (1.2 kg) suggest that it was a heavy-duty tool (sensu Clark tools were found there. 2001). Similar examples of shaped elongated cobbles are a characteristic feature of several other assemblages in the Kap- Discussion and Conclusions thurin Formation (Cornelissen 1992, 1995) and may suggest affinities with the Sangoan industrial complex, found else- The Koimilot assemblages show Levallois flake production by where stratified between Acheulian and MSA assemblages the preferential method and the recurrent method (sensu In- (Clark 1999, 2001; McBrearty 1987). However, heavy-duty izan et al. 1999) from centripetally prepared cores. In addition, tools are poorly defined in general and occur at African sites the Locus 2 assemblage preserves large (∼10 cm) elongated from throughout the Pleistocene and (e.g., Clark triangular Levallois flakes or points struck from cores pre- 2001; Gowlett 1999). Rather than being indicative of a par- pared by unidirectional and convergent flaking. This dem- ticular tool , they may simply reflect an expedient onstrates considerable variability in the methods of producing technology that satisfies a persistent hominin need for heavy- Levallois flakes of different morphologies at ∼250,000 years duty tools. ago in eastern African lithic assemblages, variability compa- The younger Locus 2 lithic assemblage consists of flakes, rable to that seen among European and Levantine Middle flake fragments, cores, and core fragments (table 1, fig. 3) Paleolithic sites. Artifact assemblages from both loci are at- made of the same raw materials found at Locus 1 but in tributed to the MSA because of the presence of Levallois 372 Current Anthropology Volume 47, Number 2, April 2006

Fig. 3. Artifacts from Koimilot locus 2, including elongated preferential Levallois flakes primarily produced by unidirectional or convergent flak- ing (a–e) and a core from which such flakes were produced (f )from nearby Locality 117 at the same stratigraphic interval, a blade or bladelet core (g), and a centripetally prepared recurrent Levallois core with re- fitting shaping flake (h). Artifacts d and e are from the surface; all other Locus 2 artifacts are from excavation, and all are of fine-grained lava. Arrows show the direction of flake removal and presence or absence of the negative of the bulb of percussion. Blank scars are those for which flake removal orientation is unclear. technology and the absence of handaxes, cleavers, or other duction strategies. However, in the Kapthurin Formation, the Acheulian tools. Because of its antiquity, Koimilot is an early earliest evidence for Levallois technology is found among MSA site. Acheulian sites dating to ∼284,000–510,000 years ago (Deino The stratigraphic position of Koimilot in the upper portion and McBrearty 2002). Sites such as the Leakey Handaxe Area of the Kapthurin Formation archaeological succession is es- show the use of centripetally prepared, boulder-sized lava tablished on the basis of field and geochemical correlation of cores for the production of large (∼10–20 cm) Levallois flakes, volcanic ash deposits (Tryon 2003; Tryon and McBrearty 2002, some of which were transformed into large cutting tools such n.d.). Sites older than Koimilot are 1284,000 years old and as cleavers (Leakey et al. 1969; Tryon n.d.; Tryon, McBrearty, demonstrate the persistent manufacture of Acheulian imple- and Texier n.d.) Thus, in the Kapthurin Formation and else- ments after the advent of those considered characteristic of where, Levallois flake production is a late Acheulian phenom- the MSA, resulting in the interstratification of handaxe- and enon, and it is the diversification rather than the origin of point-bearing strata. Flake production strategies among these Levallois technology that is the hallmark of the MSA (cf. sites are variable, and some preserve shaped elongated cobbles Balout 1967; Tryon, McBrearty, and Texier n.d.). comparable to the pointed uniface from Koimilot Locus 1. Documenting temporal and geographic patterning in Le- Koimilot is differentiated from these earlier sites primarily by vallois technology found at both Acheulian and MSA sites the shift to a Levallois system of flake and tool blank pro- can make an important contribution to our understanding 373 of industrial change and the origins of regionalization in the written during my tenure at the Centre d’E´ tudes Pre´histoire, African Pleistocene record (Clark 1988; Wurz 2002). Cer- Antiquite´ et Moyen-Aˆ ge (CNRS, Sophia-Antipolis, France) tainly, the Kapthurin Formation evidence argues against any while supported by a postdoctoral fellowship from the Fyssen sudden, complete, or unidirectional change across the Acheu- Foundation and as a postdoctoral fellow at the Smithsonian lian-MSA transition, and similarities between methods of Le- Institution (National Museum of Natural History). I thank vallois flake production at Koimilot and older Acheulian sites Sally McBrearty, Pierre-Jean Texier, Lilliane Meignen, and may indicate technological continuity due to the persistence Rick Potts for guidance, as as Marta Camps, Benjamin of local hominin populations (Marean and Assefa 2005). Orlove, and three anonymous reviewers, who suggested val- However, despite the recent prominence of Levallois tech- uable ways to improve the manuscript. Finally, I thank my nology as a population marker, similarities may also be due family and friends, particularly my wife, Rhonda Kauffman, to functional convergence (cf. Brantingham and Kuhn 2001; for their tireless support and patience. Foley and Lahr 1997). Numerous factors that affect lithic assemblage composition and artifact form are directly relevant to an understanding of Levallois technology and the Acheu- lian-MSA transition and may help to explain the patterning References Cited observed in the Kapthurin Formation. These factors are being Ashton, Nicolas, John McNabb, and Simon Parfitt. 1992. addressed in continued research and include raw-material Choppers and the : A reinvestigation. Proceed- constraints, site or artifact function, occupation duration, and ings of the Prehistoric Society 58:21–28. sampling bias during excavation (e.g., Rolland and Dibble Balout, Lionel. 1967. Proce´de´s d’analyse et questions de ter- 1990). minologie dans l’e´tude des ensembles industriels du Pale´o- Ultimately, the study of lithic artifacts during the Acheu- lithique infe´rieur en Afrique du Nord. In Background to lian-MSA transition provides the basic framework needed to evolution in Africa, ed. W. W. Bishop and J. D. Clark, initiate a broader understanding of more complex issues such 707–36. Chicago: University of Chicago Press. as shifts in hominin subsistence, landscape use, and social Bar-Yosef, Ofer. 2000. The Middle and Early behavior. Lithic technological changes throughout the later in southwest Asia and neighboring regions. In The geog- Middle Pleistocene seen at Koimilot and other Kapthurin raphy of and modern in Europe and Formation sites suggest considerable complexity within a sin- the greater Mediterranean, ed. O. Bar-Yosef and D. Pilbeam, gle depositional basin (McBrearty, Bishop, and Kingston 107–56. Cambridge: Peabody Museum of Archaeology and 1996), a finding echoed by studies in the Middle Awash region Ethnology, Harvard University. of (Clark et al. 2003) and at Sai Island, Sudan (Van Beyries, Sylvie, and E´ ric Boe¨da. 1983. E´ tude technologique et Peer et al. 2003). A synthetic review of evidence from the traces d’utilisation des “e´clats de´bordants” de Corbehem Kapthurin Formation and elsewhere in Africa suggests the (Pas-de-Calais). Bulletin de la Socie´te´Pre´historique Franc¸aise mosaic and incremental addition of novel behaviors by local 80:275–79. hominin populations in Africa throughout the Middle and Boe¨da, E´ ric. 1993. Le de´bitage discoı¨deetlede´bitage Levallois Later Pleistocene (McBrearty and Brooks 2000). The evidence re´current centripe`te. Bulletin de la Socie´te´Pre´historique considered here from Koimilot and other sites in the Kap- Franc¸aise 90:392–404. thurin Formation extends this interpretation. In particular, ———. 1994. Le concept Levallois: Variabilite´ des me´thodes. the variable presence or absence of different tool types such Paris: Centre National de la Recherche Scientifique E´ d- as points, variation in the particular method used for Levallois itions. flake production, and the existence of Levallois flakes and Boe¨da, E´ ric, and Jacques Pelegrin. 1979. Approche techno- cores in the late Acheulian imply that this incremental pattern logique du nucleus Levallois a e´clat. E´tudes Pre´historiques of change includes the very elements of lithic technology that 15:41–48. define the Middle Stone Age. Bradley, Bruce A., and C. Garth Sampson. 1986. Analysis by replication of two Acheulian artefact assemblages from Acknowledgments Caddington, England. In Stone Age : Studies in My research in the Kapthurin Formation has been supported honor of Charles McBurney, ed. G. N. Bailey and P. Callow, by doctoral dissertation improvement grants from the Na- 29–45. Cambridge: Cambridge University Press. tional Science Foundation (BCS-0118345), the Wenner-Gren Brantingham, P. Jeffrey, and Steven L. Kuhn. 2001. Con- Foundation, the Leakey Foundation, the University of Con- straints on Levallois core technology: A mathematical necticut Research Foundation, and the Bill Bishop Memorial model. Journal of Archaeological Science 28:747–61. Trust. Excavation was conducted under research permit Chapman, Gregory R. 1971. The geological evolution of the MOEST 13/001/30C 229 from the Government of the Re- northern Kamasia Hills, Baringo District, Kenya. Ph.D. public of Kenya and an exploration and excavation license diss., University of London. from the Minister for Heritage and Sports. This article was Clark, J. Desmond. 1988. The Middle Stone Age of East Africa 374 Current Anthropology Volume 47, Number 2, April 2006

and the beginnings of regional identity. Journal of World Isaac, Glynn L., J. W. K. Harris, and Ellen M. Kroll. 1997. Prehistory 2:235–305. The stone artefact assemblages: A comparative study. In ———. 1999. Cultural continuity and change in hominin The Koobi Fora research project, vol. 5, Plio-Pleistocene ar- behaviour in Africa during the Middle to Upper Pleistocene chaeology, ed. G. Isaac and B. Isaac, 262–306. Oxford: Clar- transition. In Hominin evolution: Lifestyles and survival endon Press. strategies, ed. H. Ullrich, 277–92. Gelsenkirchen/Schwelm: Klein, Richard G. 1999. The career. Chicago: University Edition Archaea. of Chicago Press. ———. 2001. prehistoric site. Vol. 3. The earlier Kuhn, Steven L. 1995. lithic technology: An eco- cultures: Middle and Earlier Stone Age. Cambridge: Cam- logical perspective. Princeton: Princeton University Press. bridge University Press. Lahr, Marta M., and Robert Foley. 1998. Towards a theory of Clark, J. D., Y. Beyene, G. Woldegabriel, W. K. Hart, P. Renne, modern human origins: Geography, demography, and di- H. Gilbert, A. Defleur, G. Suwa, S. Katoh, K. R. Ludwig, versity in recent . Yearbook of Physical An- J-R. Boisserie, B. Asfaw, and T. D. White. 2003. Strati- thropology 41:137–76. graphic, chronological, and behavioural contexts of Pleis- Leakey, Margaret, Philip V. Tobias, John E. Martyn, and Rich- tocene Homo sapiens from Middle Awash, Ethiopia. ard E. F. Leakey. 1969. An Acheulian industry with prepared 423:747–52. core technique and the discovery of a contemporary hom- Conard, Nicholas J., Marie Soressi, John E. Parkington, Sarah inin mandible at Lake Baringo, Kenya. Proceedings of the Wurz, and Royden Yates. 2004. A unified lithic taxonomy Prehistoric Society 3:48–76. based on patterns of core reduction. South African Ar- Le Gall, B., J-J. Tiercelin, J-P. Richert, P. Gente, N. C. Sturchio, chaeological Bulletin 59:13–17. D. Stead, and C. Le Turdu. 2000. A morphotectonic study Cornelissen, Els. 1992. Site GnJh-17 and its implications for of an extensional fault zone in a magma-rich rift: The Bar- the archaeology of the middle Kapthurin Formation, Baringo, ingo Trachyte Fault System, central Kenya Rift. Tectono- Kenya. Muse´e Royale de l’Afrique Centrale, Annales, Sci- physics 320:87–106. ences Humaines 133. McBrearty, Sally. 1987. Une e´valuation du Sangoen: Son aˆge, ———. 1995. Indications du post-Acheule´en (Sangoen) dans son environnement et son rapport avec l’origine de l’Homo la formation Kapthurin, Baringo, Kenya. L’Anthropologie sapiens. L’Anthropologie 91:497–510. 99:55–73. ———. 1999. Archaeology of the Kapthurin Formation. In Deino, Alan, and Sally McBrearty. 2002. 40Ar/39Ar chronology Late Cenozoic environments and hominin evolution: A tribute for the Kapthurin Formation, Baringo, Kenya. Journal of to Bill Bishop, ed. P. Andrews and P. Banham, 143–56. Lon- Human Evolution 42:185–210. don: Geological Society. Foley, Robert, and Marta M. Lahr. 1997. Mode 3 ———. 2001. The Middle Pleistocene of East Africa. In Hu- and the evolution of modern humans. Cambridge Archae- man roots: Africa and Asia in the Middle Pleistocene, ed. L. ological Journal 7:3–36. H. Barham and K. Robson-Brown, 81–97. Bristol: Western Geneste, Jean-Michel. 1985. Analyse lithique d’industries Academic and Specialist Press. mouste´riennes du Pe´rigord: Une approche technologique McBrearty, S., L. C. Bishop, and J. D. Kingston. 1996. Vari- du comportement des groupes humains au Pale´olithique ability in traces of Middle Pleistocene hominid behavior in moyen. Ph.D. diss., Universite´ de Bordeaux I. the Kapthurin Formation, Baringo, Kenya. Journal of Hu- Gowlett, John A. J. 1999. Lower and Middle Pleistocene ar- man Evolution 30:563–80. chaeology of the Baringo Basin. In Late Cenozoic environ- McBrearty, Sally, and Alison Brooks. 2000. The revolution ments and hominin evolution: A tribute to Bill Bishop, ed. that wasn’t: A new interpretation of the origin of modern P. Andrews and P. Banham, 123–41. London: Geological human behavior. Journal of Human Evolution 39:453–563. Society. McBrearty, Sally, and Nina G. Jablonski. 2005. First fossil Henshilwood, Christopher S., and Curtis W. Marean. 2003. chimpanzee. Nature 437:105–8. The origin of modern human behavior: Critique of the McBrearty, Sally, and Christian A. Tryon. 2005. From Acheu- models and their test implications. Current Anthropology lian to Middle Stone Age in the Kapthurin Formation of 44:627–51. Kenya. In Transition before the transition: Evolution and Howell, F. Clark. 1999. Paleo-demes, species clades, and ex- stability in the Middle Paleolithic and Middle Stone Age, ed. tinctions in the Pleistocene hominin record. Journal of An- E. Hovers and S. L. Kuhn, 257–77. New York: Springer. thropological Research 55:191–243. McDougall, Ian, Frank H. Brown, and John G. Fleagle. 2005. Inizan, Marie-Louise, Miche`le Reduron-Ballinger, He´le`ne Stratigraphic placement and age of modern humans from Roche, and Jacques Tixier. 1999. Technology and terminol- Kibish, Ethiopia. Nature 433:733–36. ogy of knapped stone. Nanterre: CREP. Marean, Curtis A., and Zelalem Assefa. 2005. The Middle and Isaac, Glynn L. 1977. Olorgesailie: Archaeological studies of a Upper Pleistocene African record for the biological and Middle Pleistocene lake basin in Kenya. Chicago: University behavioral origins of modern humans. In African archae- of Chicago Press. ology, ed. A. B. Stahl, 93–129. Oxford: Blackwell. 375

Marks, Anthony, and Philip Volkman. 1987. Technological Tryon, Christian A. 2002. Middle Pleistocene sites from the variability and change seen through core reconstruction. In “southern” Kapthurin Formation of Kenya. Nyame Akuma The human uses of flint and chert, ed. G. de G. Sieveking 57:6–13. and M. H. Newcomer, 11–20. Cambridge: Cambridge Uni- ———. 2003. The Acheulian to Middle Stone Age transition: versity Press. Tephrostratigraphic context for archaeological change in Mehlman, Michael J. 1989. Late Quaternary archaeological the Kapthurin Formation, Kenya. Ph.D. diss., University of sequences in northern Tanzania. Ph.D. diss., University of Connecticut. Illinois. ———. n.d. Le concept Levallois en Afrique. Annales Fyssen. Meignen, Lilliane. 1996. Persistance des traditions techniques In press. dans l’abri des Canalettes (Nant-Aveyron). Quaternaria Tryon, Christian A., and Sally McBrearty. 2002. Tephrostra- Nova 6:449–64. tigraphy and the Acheulian to Middle Stone Age transition Mourre, Vincent. 2003. Discoı¨de ou pas discoı¨de? Re´flexions in the Kapthurin Formation, Baringo, Kenya. Journal of sur la pertinence des crite`res techniques de´finissant le de´- Human Evolution 42:211–35. bitage discoı¨de. In Discoid lithic technology: Advances and ———. n.d. Tephrostratigraphy of the Bedded Tuff Member implications, ed. M. Peresani, 1–18. British Archaeological (Kapthurin Formation, Kenya) and the nature of archae- Reports International Series 1120. ological change in the later Middle Pleistocene. MS. Petraglia, Michael D., and Ravi Korisettar, eds. 1998. Early Tryon, Christian A., Sally McBrearty, and Pierre-Jean Texier. human behavior in global context: The rise and diversity of n.d. Levallois lithic technology from the Kapthurin For- the record. London: Routledge. mation, Kenya: Acheulian origin and Middle Stone Age Pleurdeau, David. 2003. Le Middle Stone Age de la grotte du diversity. African Archaeological Review. In press. Porc-E´ pic (Dire Dawa, E´ thiopie): Gestion des matie`res pre- Tuffreau, Alain. 1995. Variability of Levallois technology in mie`res et comportements techniques. L’Anthropologie 107: northern France and neighboring areas. In The definition 15–48. and interpretation of Levallois technology, ed. H. L. Dibble Rolland, Nicholas, and Harold L. Dibble. 1990. A new syn- and O. Bar-Yosef, 413–31. Madison: Prehistory Press. thesis of Middle Paleolithic variability. American Antiquity Van Peer, Philip. 1992. The Levallois reduction strategy. Mad- 55:480–99. ison: Prehistory Press. Tallon, Peter W. J. 1976. The stratigraphy, palaeoenviron- ———. 1998. The Nile Corridor and the Out-of-Africa ments, and geomorphology of the Pleistocene Kapthurin model: An examination of the archaeological record. Cur- Formation, Kenya. Ph.D. diss., Queen Mary College. rent Anthropology 39:S115–40. ———. 1978. Geological setting of the hominin fossils and Van Peer, P., R. Fullagar, S. Stokes, R. M. Bailey, J. Moeyersons, Acheulian artifacts from the Kapthurin Formation, Baringo F. Steenhudt, A. Geerts, T. Vanderbeken, M. de Dapper, District, Kenya. In Geological background to fossil man, ed. and F. Geus. 2003. The Early to Middle Stone Age transition W. W. Bishop, 361–73. Edinburgh: Scottish Academic Press. and the emergence of modern human behavior at site 8- Texier, Pierre-Jean. 1996. Evolution and diversity in flaking B-11, Sai Island, Sudan. Journal of Human Evolution 45: techniques and methods in the Palaeolithic. In Proceedings 187–94. of the U.I.S.P.P. XIII Congre`s, ed. A. Andreoni, C. Giunchi, Villa, Paola. 1983. Terra Amata and the Middle Pleistocene C. Peretto, and I. Zavatti, 297–325. Forlı`, Italy: ABACO. archaeological record of southern France. University of Cal- Tishkoff, S. A., and S. M. Williams. 2002. Genetic analysis of ifornia Publications in Anthropology 13. African populations: Human evolution and complex dis- White, T. D., B. Asfaw, D. DeGusta, H. Gilbert, G. D. Richards, ease. Nature Reviews Genetics 3:611–21. G. Suwa, and F. C. Howell. 2003. Pleistocene Homo sapiens Tixier, Jacques. 1974. Glossary for the description of stone tools, from Middle Awash, Ethiopia. Nature 423:742–47. with special reference to the Epipaleolithic of the Maghreb. Wurz, Sarah. 2002. Variability in the Middle Stone Age lithic Translated by M. H. Newcomer. Newsletter of Lithic Tech- sequence, 115,000–60,000 years ago at Klasies River, South nology Special Publication 1. Africa. Journal of Archaeological Science 29:1001–15.