Journal of Archaeological Science 40 (2013) 4528e4537

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Journal of Archaeological Science

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Investigating experimental knapping damage on an antler : a pilot-study using high-resolution imaging and analytical techniques

Silvia M. Bello a,*, Simon A. Parfitt a,b, Isabelle De Groote a,c, Gabrielle Kennaway d a Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK b Institute of Archaeology, University College London, 31-34 Gordon Square, London WC1H 0PY, UK c Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK d Imaging and Analysis Centre, The Natural History Museum, Cromwell Road, London SW7 5BD, UK article info abstract

Article history: Organic (bone, antler, wood) knapping tools were undoubtedly a component of early human tool kits Received 8 March 2013 since the Lower Palaeolithic. Previous studies have identified pitting and the occasional presence of Accepted 13 July 2013 embedded flint flakes as important features for recognizing archaeological bone and antler percussors. However, no systematic protocol of analysis has been suggested for the study of this rare archaeological Keywords: material. Here we present qualitative and quantitative results of a preliminary analysis of an experi- fl Antler int-knapping hammer mental knapping hammer, using a novel combination of microscopy (focus variation optical microscope CT-scanning and scanning electron microscope), micro-CT scanning and energy dispersive X-ray spectroscopy. These Focus variation optical microscope Scanning electron microscope imaging and analytical techniques are used to characterize use-damage from the manufacture of han- Energy-dispersive X-ray spectroscopy daxes. This paper highlights the strengths and weakness of each technique. Use-wear on the working area included attritional bone loss, micro-striations and compaction of the outer layer of the antler matrix from repeated hitting of the beam against the sharp edge of the handaxe during knapping. Embedded flint flakes were also identified in the pits and grooves. This combination of high-resolution imaging techniques is applicable to fragile archaeological specimens, including those encrusted by sediment or encased in matrix. Ó 2013 Elsevier Ltd. All rights reserved.

1. Introduction presence of small flint chips embedded in the surface of an antler that can ultimately confirm the use of an antler as a tool-maker. In recent years, new and increasingly sophisticated imaging and These small flint residues can be observed using a hand lens and analytical techniques have been applied to the study of past human binocular microscope at low magnification, but more informative behaviour: optical and laser microscope, X-ray, CT and Micro-CT results can be obtained using higher magnification photography scans, just to mention a few (e.g. Abel et al., 2012; Bello et al., and scanning electron microscopy (Bordes, 1974; Mallye et al., 2013; Boschin and Crezzini, 2012; Evans and Donahue, 2008; Le 2012; Olsen, 1989). Bourdonnec et al., 2010). The use of soft (bone, antler, wood) Several experimental studies have explored the use of bones as and retouchers was a key innovation in early soft-hammers and retouchers, either as percussors or pressure technology, first recorded in the archaeological record during flakers (e.g. Karavanic and Sokec, 2003; Mallye et al., 2012; Lower Palaeolithic (Acheulian of Boxgrove, UK w500 kya; Wenban- Newcomer, 1971; Rosell et al., 2011; Semenov, 1964; Wenban- Smith, 1985, 1999). The use of antlers as soft hammers can be Smith, 1985, 1999), however, antler knapping-hammers have identified from characteristic damage on the working area in form received little systematic attention (Lyman, 1994; but see Bordes, of micro-fractures. These have been described and recognized since 1974; Olsen, 1989; Shipman and Rose, 1983). This is surprising as the beginning of the 20th century (e.g. Bourlon, 1907; Girod and antler is the preferred soft-hammer for thinning and finishing of Massenat, 1900; Henri-Martin, 1907e1910). However it is the experimental handaxes, scrapers and Upper Palae- olithic blades (Bordes, 1974; Crabtree, 1970; Flenniken, 1984; Johnson, 1978; Knowles, 1953; Newcomer, 1971; Ohnuma and

* Corresponding author. Tel.: þ44 0207 942 5141. Bergman, 1982; Whittaker, 1994; Wymer, 1968). The lack of E-mail addresses: [email protected], [email protected] (S.M. Bello). detailed documentation and description of traces of use on antler

0305-4403/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jas.2013.07.016 S.M. Bello et al. / Journal of Archaeological Science 40 (2013) 4528e4537 4529 knapping-percussors presents a major stumbling block to identi- resulting in the removal of small chips, followed by a sharper blow fying fragmentary (Jéquier et al., 2012), poorly preserved, to detach a larger thinning and trimming flake (Fig. 2B). sediment-encrusted (Kuhn et al., 2008) or contentious archaeo- The antler bar-hammer was selected for this pilot study because logical examples (Goren-Inbar, 2011). of its shape, lack of tines and overall small dimensions which This paper presents the results of a preliminary analysis to facilitate micro-computed tomography and SEM analyses. Similar document use-damage on an experimental knapping hammer us- bar-hammers are used widely by experimental flint-knappers, ing a range of analytical and imaging techniques (i.e. micro- particularly in North America (Crabtree, 1967). computed tomography, focus variation microscopy, variable pres- sure scanning electron microscopy and energy dispersive X-ray 3. Methods spectroscopy). The strength and weakness of each technique have been highlighted. We illustrate microscopic use-wear features that The antler was examined initially with a variable magnification are diagnostic of antler knapping hammers and propose a protocol binocular and observations were aided by illumination from a fibre- for their analysing. optic light source. Drawings were used to record the location and intensity of damage, and to indicate the position of the flint chips. 2. Material An un-modified area of the antler used as a control for surface texture was also analysed. This corresponds to its central basal The soft hammer used in the experimental study (Fig. 1A) was portion, where the hammer was held (Fig. 1F). Comparisons were cut from the beam of an antler of a whitetail deer (Odocoileus vir- also made with natural surface modifications on antlers described ginianus) using a metal saw. Although cuts are still visible at the by Olsen (1989), d’Errico and Villa (1997) and Jin and Shipman base (‘handle’) of the hammer, extensive use-damage has removed (2010). all but a vestige of the saw-marks at the ‘apical’ end (Fig. 1B). The Micro-computed tomography (micro-CT) was undertaken to hammer was part of the tool-kit used during flint-knapping ex- record the surface topography and to gauge the extent of surface periments conducted at Boxgrove between 1995 and 1996. These damage in relation to antler density. The specimens were scanned experiments replicated sharp ovate handaxes similar to those using a HMX-ST CT 225 System (Metris X-Tek, Tring, UK). The in- found in the early Middle Pleistocene archaeological horizons at the strument uses a cone beam projection system (Johnson et al., 2007) site (Roberts and Parfitt, 1999). The tool-kit used by the flint with a four megapixel Perkin Elmer XRD 1621 AN3 HS detector knappers consisted of a hard (flint beach pebble) hammer, a soft panel. Different settings were used to optimize contrast and hammer made from the base of a red deer antler and a lighter minimize beam hardening. The final X-ray and scan parameters (172 g) antler bar-hammer, which is the focus of this study. were as follows: tungsten target; 175 kV; 145 mA; 6284 projections Weathered flint nodules (from soliflucted gravels) and fresh flint with 0.354 s exposure and a voxel size of 42.9 mm. In order to reduce from chalk exposures in the at Boxgrove were used to the effects of beam hardening the X-rays were filtered with a manufacture handaxes. The antler hammer was held at the prox- 0.5 mm thick copper plate. The long axis of the antler was oriented imal end and struck against the tool-edge to detach flakes. Mostly, vertically with respect to the beam, thus ensuring maximum res- the knapper struck the hammer at right angles to the handaxe edge, olution whilst minimizing streak artefacts (Yu et al., 2004). The but it was sometimes held at an oblique angle, or even parallel to micro-CT data were reconstructed using CT-PRO software version the edge. Flaking alternated between a succession of light blows to 2.0 (Metris X-Tek) and rendered using VG Studio MAX 2.1 (Volume first prepare and strengthen the striking platform (Fig. 2A), Graphics, Heidelberg, Germany).

Fig. 1. (A) Photograph and longitudinal and transverse CT sections (BeC) of the experimental antler hammer. (D) CT surface rendering showing position of the cross-sections CS1e3. The original profile of the working area is indicated by the dashed lines. Scales A, B and D ¼ 50 mm; C, E and F ¼ 10 mm. 4530 S.M. Bello et al. / Journal of Archaeological Science 40 (2013) 4528e4537

Fig. 2. Drawings showing how the experimental antler hammer was used (A) to remove thinning flakes, and (B) strengthen the platform.

To explore the micro-topography of the use-damage we scattered electron (BSE) images to be obtained without the appli- employed focus variation microscopy (FVM), using the Alicona cation of a conducting layer on the specimen. Topographic BSE Infinite Focus microscope (AIFM). The AIFM combines a short depth imaging mode was used to reduce elemental contrast between light of focus with vertical scanning to produce a true-colour rendering element-rich silica (with a low BSE coefficient, hence dark) and of the surface in three dimensions (Bello and Soligo, 2008; Bello bone, with calcium and phosphorus giving a higher BSE coefficient et al., 2009, 2011; Danzl et al., 2009). Area and linear measure- (bright). The operating parameters were: accelerating voltage of ments were recorded from the 3D model using MeX software; 15 kV; spot size 500; pole-piece to specimen working distance of measurements were calibrated to conform to ISO standards. Typi- 15 mm. Energy-dispersive X-ray (EDX) microanalysis was carried cally, images were captured using a 2.5 objective lens (magnifi- out using an Oxford Instruments X-Max 80 Silicon Drift Detector cation 45.72) and a vertical and lateral resolution of 10 mm and and INCA software. The working distance between the specimen 3.47 mm respectively; a 5 objective (magnification 91.44, vertical and the EDX detector varied between 14 mm and 22 mm. This resolution ¼ 1.74 mm, lateral resolution ¼ 1.49 mm) was used to configuration was used to intercept X-rays from a broad area, which record features of the embedded flint fragments and morphology of is more suitable for elemental mapping. the surface marks. To examine differences in the density and dis- tribution of knapping damage, we divided the apical end of the 4. Results antler into horizontal zones (‘basal zone’, BZ; ‘apical zone’, AZ), which were further subdivided vertically into sectors (‘left sector’, The surface of the antler used for hammering displays extensive LS; ‘central sector’, CS and ‘right sector’, RS; Fig. 3AeB). The mod- modification, with the most concentrated damage near the apical ifications were scored according to the classification of Mallye et al. end covering an area of about 240 mm2. The intensity of use is (2012, Fig. 2, page 1134), who defined ‘pits’ as depressions with a visible on the CT sections (Fig. 1BeC), which illustrate attritional sub-triangular or ovoid form, and ‘scores’ as depressions with a loss of the outer cortical surface towards the apex. In this area, the linear form. cortical bone has been penetrated and the internal trabecular tissue To record finer details of the use-damage we examined selected exposed (Fig. 1C e Cross-sectional profile 1, CS1). The CT sections areas using a LEO1455VP scanning electron microscope (SEM). also show increased density of the outer-layer of the cortex asso- Images were captured at high resolution (3 nm) and at a magnifi- ciated with the percussion damage. This reflects the compaction of cation ranging from about 40 to 600. The SEM was operated in the surface due to repeated compression from hammering (Fig. 4B). variable pressure mode (chamber pressure 15 Pa), enabling back- Heavy pitting in form of overlapping grooves and flaking is S.M. Bello et al. / Journal of Archaeological Science 40 (2013) 4528e4537 4531

Fig. 3. (A) Drawing showing the subdivision of the working area of the experimental hammer into sectors (LS, CS, RS) and zones (AZ, BZ), and their corresponding FVM images (B and C) with the location of pits (red dots), rectilinear scores (green lines) and embedded flint chips (white boxes 1e7). Only complete pits and scores are indicated. (D) FVM image of unmodified area with (E) the locations of natural indentations (yellow boxes). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) common on the working area of the hammer. Microscopically, inclusions exhibited silicon picks which distinguish them from the modifications on this area include crushing, micro-flaking, abra- surrounding bone. The large silicon and oxygen peaks in Fig. 5B sion, striations and numerous overlapping and intercutting de- spectra 1 to 4 (S1eS4) indicate the presence of silicon dioxide pressions (Fig. 1E). The most common types of damage are (SiO2), either as a crystalline material such as or a crypto- indentations and gouges. Pits are often associated with micro- crystalline material like flint or . The conchoidal fracture on cracks and crushing, and internal micro-striations are sometimes the flake (Fig. 6) is also typical of the fracture pattern of micro- observed within and on the flanks of the pits. Grooves are V-shaped crystalline silica. Analyses of the surrounding matrix (Fig. 5B, S5e notches, which are generally asymmetrical in cross-section. These S7) showed the presence of calcium and phosphorus peaks typical features are occasionally associated with rounding and polishing of of bone. Smaller peaks representing carbon, aluminium and iron the edges of the indentations. The morphology and microscopic are probably associated with environmental contamination from details of the grooves are reminiscent of chop-marks made with a soil and handling (sulphur, carbon and potassium). The EDX maps stone tool (Shipman, 1981). Overall, pits (n ¼ 271) are more also clearly show that the flakes contain high silicon levels, that the numerous than scores (n ¼ 74; Fig. 3C). Pits are not distributed surrounding matrix was calcium-rich (bone) and that the evenly over the three vertical sectors, but are more concentrated in aluminium-bearing contamination was distributed in minute par- the apical zone of the hammer (this difference is statistically sig- ticles across the surface (Fig. 7). The flint chips identified using SEM nificant, Chi2 test, p < 0.0001; Figs. 1 and 3C; Table 1). Scores are and EDX, were measured with the FVM. The flint chips were more frequent in the central region, where they are evenly generally small, with an average length of 1.13 mm, an average distributed between the basal and apical zones. Scores are less width of 0.47 mm and an average surface area of 0.81 mm2. In all frequent in the lateral sectors, where they are unevenly distributed but one case, the flints were elongate (i.e. length at least twice the between the basal and apical zones (Fig. 3C; Table 1). The non- width measurement). random distribution of pits and scores appeared to be associated None of these modifications are found on the handle of the with the most intensively used region of the apical portion (Figs. 1 antler hammer. There is no loss of outer cortical surface or and 3C; Table 1). For all worked zones, scores were on average compression of the trabecular surface (Fig. 1C e CS2 and CS3). Only longer (mean length 4.05 mm) than pits (mean length 1.96 mm; a few non-overlapping, scattered and shallow indentations are t ¼ 16.70, df ¼ 343, p < 0.001) and pits (mean depth 210.8 mm) were visible (Fig. 1F). These have predominantly a linear form and seem generally deeper than scores (mean depth 156.8 mm; t ¼ 3.81, to be randomly scattered without a preferential orientation df ¼ 343, p ¼ 0.001; Table 2). (Fig. 3E). Occasionally, they are associated with micro-cracks and Examination under the binocular microscope of the apical sur- crushing, but no internal micro-striations are visible. These marks, face of the antler resulted in the identification of seven putative with an average length of 2.22 mm, width of 0.31 mm and depth of flint chips embedded in six scores and one pit. EDX spectra of five 74.36 mm, were consistently different from any of the two types of 4532 S.M. Bello et al. / Journal of Archaeological Science 40 (2013) 4528e4537

Fig. 4. (A) CT-rendering of the apex of the experimental hammer, showing micro-topography of the use-wear and the location of embedded flint chips (1e5, 7). (BeC) Apical CT cross-sections, showing fractured flint chip (5aeb) and cracks in the outer surface of the antler (white arrows). The higher density of the working surface (black arrows) is due to compaction of the antler cortex. Scale: B ¼ 5 mm; C ¼ 1 mm.

Table 1 indentations observed on the worked area of the antler (Table 3). Number of non-overlapping pits and grooves according to their location on the Although more similar to scores in their overall dimensions, they experimental antler hammer (Fig. 3C). differed from these in being slightly longer, but significantly nar- LS CS RS Total rower (t ¼ 13.6, df ¼ 296, p < 0.001) and shallower (t ¼ 6.224, df ¼ 296, p < 0.001). The metrical characteristics of the marks on Pits Grooves Pits Grooves Pits Grooves Pits Grooves the handle suggest that they were produced by processes other AZ 57 14 53 21 84 8 194 43 than knapping and were more similar to natural modifications BZ 30 7 39 19 8 5 77 31 ’ Total 87 21 92 40 92 13 271 74 produced during the life or the deer (Olsen, 1989; d Errico and Villa, 1997; Giacobini and Patou-Mathis, 2002; Jin and Shipman, 2010;

Table 2 Mean values of length, width (in mm) and depth (in mm) of non-overlapping pits and scores according to their location on the used area of the experimental antler hammer.

LS CS RS Total

Length Width Depth Length Width Depth Length Width Depth Length Width Depth (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm)

Pits AZ 2.23 1.72 219.8 1.94 1.49 257.5 1.79 1.32 203.0 1.96 1.48 222.8 BZ 1.80 1.41 151.2 2.33 0.73 208.5 2.00 1.50 155.1 2.09 1.59 180.6 2.08 1.61 196.2 2.10 1.60 236.7 1.81 1.33 198.8 Mean 1.99 1.51 210.8 Max 4.31 3.01 540.04 Min 1.00 0.52 17.24 SD 0.55 0.46 112.91 Grooves AZ 3.90 0.87 160.7 3.87 0.73 158.5 4.80 0.79 185.4 4.05 0.79 164.2 BZ 3.16 067 114.6 3.07 0.69 145.0 4.28 0.74 196.6 3.28 0.69 146.5 3.65 0.81 145.4 3.49 0.71 152.1 4.60 0.77 189.7 Mean 3.73 0.75 156.8 Max 8.72 1.81 440.56 Min 1.79 0.23 29.16 SD 1.35 0.29 88.84 S.M. Bello et al. / Journal of Archaeological Science 40 (2013) 4528e4537 4533

Fig. 5. (A) Photograph of the apical working area of the experimental antler hammer with embedded flint chips 4 and 5 (scale 10 mm). (B) SEM image of the hammer using backscattered electrons, with points analysed by energy dispersive X-ray spectroscopy (EDX; S1e7). The horizontal axis of the spectrum is the X-ray energy and the vertical axis is the total number of X-rays counted. The peak at zero keV is generated by the instrument electronics as a reference. (C) Coloured digital elevation model generated using the focus variation optical microscope (Alicona InfinitFocus; BeC. Scale ¼ 1 mm). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) 4534 S.M. Bello et al. / Journal of Archaeological Science 40 (2013) 4528e4537

Table 3 Length, width (in mm) and depth (in mm) of indentations on the un-used area of the experimental antler hammer (Fig. 3E).

Length (mm) Width (mm) Depth (mm)

1 0.92 0.54 183.72 2 2.20 0.27 82.56 3 1.68 0.37 58.29 4 1.91 0.29 98.38 5 3.54 0.20 49.36 6 0.21 0.19 58.84 7 1.88 0.15 36.27 8 1.97 0.17 17.34 9 3.08 0.13 36.05 10 3.58 0.29 55.29 11 6.76 0.74 170.35 12 2.40 0.20 43.86 13 1.38 0.44 92.9 14 1.95 0.36 71.51 15 1.83 0.18 30.16 16 0.42 0.28 69.07 17 0.48 0.42 26.65 18 2.30 0.55 145.65 19 1.88 0.44 110.99 20 2.68 0.29 70.5 21 3.48 0.11 30.98 22 4.29 0.23 154.29 23 0.52 0.52 81.92 24 2.02 0.30 46.68 25 1.41 0.20 37.66 26 3.74 0.20 57.67 27 1.40 0.18 90.71 Fig. 6. Stereo-pair image showing the micro-topography of embedded flint chips 4 and Mean 2.22 0.31 74.36 5 (see Fig. 5) on the experimental hammer. The arrow indicates conchoidal fractures. Max 6.76 0.74 183.72 Scale ¼ 1 mm. Min 0.21 0.11 17.34 SD 1.40 0.15 44.91

Fig. 7. (A) SEM backscattered electron image (BSE) of flint chips 4 and 5 (see Figs. 5 and 6) on the experimental hammer. (BeD) EDX maps of elemental distribution: (B) silicon, (C) aluminium and (D) calcium. (E) BSE image and combined elemental maps shown as false colours: silicon in red, calcium in blue and aluminium in green. Areas of the flint chip appear as dark in the image because of the uneven topography of the fracture surfaces, which lie below the surface of the antler and are therefore shielded from the X-ray detector. Scales ¼ 100 mm. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) S.M. Bello et al. / Journal of Archaeological Science 40 (2013) 4528e4537 4535

Malerba and Giacobini, 2002). Finally, no flint chips were observed and d’Errico, 2011). These marks can be measured using focus embedded in the handle of the antler hammer. variation microscopy and the quantitative parameters can be used to compare marks on worked and un-worked surfaces of an antler. 5. Discussion Differences in their morphology and metrical characteristics may be indicative of different knapping actions and the varying degrees The different techniques employed illustrate microscopic fea- of force required to prepare ‘platforms’ or to remove larger thinning tures that are diagnostic of antler knapping hammers. Each tech- or trimming flakes. The experimental antler hammer was used to nique has advantages and limitations for this type of analyses. knap flint using direct percussion only and therefore differences in Micro-CT scanning, as well as recording the gross 3D surface knapping action (i.e. strength of the blow and how the hammer was morphology (Fig. 1), revealed the extent of the attritional loss of the held) are probably the major factors in determining the outer cortical surface and the density differences associated with morphology of the pits and scores observed. The other important compaction due to repeated hammering (Figs. 1 and 4). Both factor determining the characteristics of the marks is the cortical loss and compression provide new discriminating features morphology of the edge of the tool against which the hammer was indicative of knapping damage on soft hammers. However, it struck. Further experiments should be undertaken to determine if should been taken into account that antlers from various cervid pits and scores are produced by different knapping actions and the species have different knapping properties and their use may effects of the strength of the blows on the morphology and size of potentially result in differences in the type and intensity of cortical the knapping damage. attritional loss. Further experimental works should be undertaken Hitherto, several authors (Bordes, 1974; Mallye et al., 2012; to establish how the intensity of hammering can affect cortical loss, Olsen, 1989) have highlighted the importance of flint chips in attrition and compaction, as these features are likely to indicate the identifying archaeological soft hammers. Recognizing flint chips duration of use in archaeological hammers and the extent to which embedded in the surface of bone and antler can be challenging these tools were curated. because of the difficulty in distinguishing them from adhering The most common types of damage observed on retouchers and sediment or concretions. In this study, five complementary tech- percussors are indentations, gouges and scores (Averbouch and niques (binocular microscopy, micro-CT scanning, FVM, SEM and Bodu, 2002; Bordes, 1974; Mallye et al., 2012; Olsen, 1989; Verna EDX) were used to aid the identification of flint chips. In all cases,

Fig. 8. SEM image and EDX spectra of flint chip 7 on the experimental hammer. Analysis of the area S1 shows a large zero peak, indicating that few X-rays are reaching the detector (i.e. the area is a ‘shadowed’ topographic low). The area S2 shows small peaks for Mg, Na, Al, Cl and K which indicate probable surface contamination. A third area of the flint (S3) is free of surface contamination and shows the characteristic peaks of silicon and oxygen. Scale ¼ 100 mm. 4536 S.M. Bello et al. / Journal of Archaeological Science 40 (2013) 4528e4537 initial interpretations based on examination with the binocular These techniques applied to the analysis of further experimental microscope were confirmed by FVM, SEM and EDX analysis. Micro- studies have the potential to unravel key questions on how ham- CT images of the experimental hammer were more difficult to mers were held and manipulated during different knapping ac- interpret without prior knowledge of their locations (Fig. 4C). This tions, the intensity and the duration of their use and therefore the was unexpected given the contrast in density between antler extent to which these tools were curated, and the identification of (mean 1.63 g/cc, range w1.50e1.72 g/cc in adult white-tailed deer; the lithic raw material and its source. Miller et al., 1985) and flint (2.57e2.64 g/cc; Deer et al., 1980). In the experimental hammer, the difference in density between the flint Acknowledgements and antler were reduced to compression and compaction of the working area, which made it difficult to locate flint chips embedded This work was part of the Ancient Human Occupation of Britain in the cortex of the antler. This problem is compounded by cracks project, funded by the Leverhulme Trust and the Human Behaviour and voids in the antler surface which can be confused with frag- in 3D project funded by the Calleva Foundation. We are grateful to ments of flint. Advantages of CT-scanning include the measure- the flint-knappers who participate in the experiments at Boxgrove ments of the angle and depth of embedded flint chips, important and to Lady Maude of Redvins for procuring the antler hammer attributes for interpreting how hammers were held during use and, described in this paper. We thank Alex Ball, Thomasz Goral and consequently, the possible determination of handedness. Anton Kearsley for their help while conducting SEM analyses. Elemental mapping and micro-probe analysis were particularly fl effective in visualizing int inclusions. However, the complex References topography (Fig. 6) complicates the collection of elemental data from some parts of the surface and prevents quantitative analysis Abel, R.L., Laurini, C., Richter, M., 2012. A palaeobiologist’s guide to ‘virtual’ micro- from this type of surface. When compared with the BSE image CT preparation. Palaeontol. Electron. 15, 1e16. Averbouch, A., Bodu, P., 2002. Fiche percuteur sur partie basilaire de bois de cervidé. (Fig. 7A), the dark areas seen in all three element distribution In: Patou-Mathis, M. (Ed.), Industrie de l’os préhistorique. Cahier X, Com- maps (Fig. 7BeD), can be seen to correspond to depressions in the presseurs, Percuteurs Retouchoirs. Editions Société Préhistorique Française, rough antler surface as well as features on the flake (fissures and Paris, pp. 103e115. cracks). Problems were also encounter using SEM images to Bello, S.M., Soligo, C., 2008. A new method for the quantitative analysis of cutmark micromorphology. J. Archaeol. Sci. 35, 1542e1552. distinguish between fractured, shattered and crushed antler and Bello, S.M., Parfitt, S.A., Stringer, C., 2009. Quantitative micromorphological analyses chips of flint that were embedded in the bottom of pits and scores. of cut marks produced by ancient and modern handaxes. J. Archaeol. 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