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General overview

1The experimental toolkit of bifacial pieces made in flint was created between December 2004 and June 2008 under the direction of É. Claud. It is comprised of 94 pieces made by three experimenters: S. Maury (78 pieces), M. Brenet (12 pieces), V. Mourre (2 pieces) and M. Lenoir (one piece) (figure 1).

Figure 1 - Experimental manufacturing of flint bifaces; on the left with an organic hammer (experimenter: S. Maury), on the right with a mineral hammerstone

Figure 1 - Experimental manufacturing of flint bifaces; on the left with an organic hammer (experimenter: S. Maury), on the right with a mineral hammerstone

Experimenter: M. Brenet

2The principal aim was to create bifaces to be used in the acquisition and transformation of different materials under different functional constraints. The second objective was to provide the products and by-products of complete knapping sequences to respond to techno-economic research questions. and the third was to test the effect of resharpening bifaces on the formation of traces of use (table 1). 81 bifaces were used on their edges on organic materials, or in some cases transported in sacks, and the resulting use-wear patterns have been described in Part I, chapter 2.10. Of these 81 bifaces, two were unfortunately not recovered at the time this inventory was compiled: one of them was used on wood and the other for skinning, 13 of the bifaces inventoried were not used experimentally and were reserved for studies of the traces related to manufacture.

Table 1 - Recording of the manufacturing sequences for the 92 bifacial tools

Experimenters

Sequences of knapping not conserved

Sequences of knapping conserved

Sequences of resharpening conserved

Total

Michel Brenet

12

12

Michel Lenoir

1

1

Serge Maury

64

7

6

77

Vincent Mourre

2

2

Total

67

19

6

92

3Information pertaining to the hammers, the techniques and the gestures of percussion and abrasion, and the order in which they were employed during manufacture were systematically considered in 21 tests. For the 71 others, only the type of hammer – mineral or organic – was recorded.

Materials and methods

4The experimental assemblage was inventoried on September 29, 2015 and includes 81 bifaces, four bifacial points and seven bifacial side scrapers in flint from different sources (primarily: Santonian flint from Charente or “Grain de Mil”, Maastrichtian flint of the Bergeracois type, Senonian flint from Dordogne). The bifaces were mostly made on flakes (59 of 92), though some were made on blocks (table 2, figures 2a-3b).

Table 2 - Flint types and blanks used for biface manufacturing

 

Type de silex

 

 

Grain de mil

Bergeracois

Senonian

Sault

Pressigny

Undetermined

Total

Plaques and blocks

5

1

6

Non-cortical flakes

29

14

1

1

45

Cortical flakes

10

4

14

Cores

2

2

Undetermined

15

4

3

1

1

1

25

Total

56

27

4

2

1

2

92

5Two thirds of the pieces are asymmetrical in cross section: planoconvex or convex / planoconvex. The rest do not show any differential surface treatment and are more or less regular and biconvex in cross section. It is worth noting that 62 of the 64 asymmetrical pieces were made on flakes while five of the seven biconvex pieces were made on plaques (table 3, figures 3a, 5b).

Table 3 - Cross section of bifaces according to the blanks used

 

Cross section

 

 

Biconvex

Convex / planoconvex

Convex / plane

Total

Nodule or plaque

5

1

6

Non-cortical flake

7

18

20

45

Cortical flake

4

5

5

14

Core

1

1

2

Undetermined

11

10

4

25

Total

28

34

30

92

Figure 2 - Bifaces with a convex distal edge (TLCAC)

Figure 2 - Bifaces with a convex distal edge (TLCAC)

a: biface on flake in "Grain de mil" flint, from Charente region, with convergent lateral cutting edges; b: biface on flake in Maastrichtien flint, from Bergerac region

Photographs: É. Claud

Typology and techno-typology of bifaces

6The experimental pieces were sorted into four primary techno-typological groups. based on structure (outline. convergence. angle. and pointedness) of their lateral edges and their point or their lateral edges and their transverse distal edges (table 4). These techno-types correspond to two primary techno-morpho-functional groups of archaeological bifaces known for the period concerned.

Table 4 - Techno-types et types de pièces bifaciales façonnées

Biface techno-types

TLCAP

TLCTDO

TLCAC

TLCTDT

TC

Total

Cordiform biface

17

3

20

Elongated cordiform biface

20

2

22

Cordiform biface with cortical butt

2

2

Pointed cordiform biface

1

1

Sub-cordiform biface

4

2

1

7

Triangular biface

4

1

5

Sub-triangular biface

8

1

9

Oval biface

1

2

2

5

Sub-oval biface

1

2

3

Lanceolate biface

3

3

Irregular biface

2

1

3

Irregular biface with cortical base

1

1

Bifacial Mousterian point

3

3

Atypical point

1

1

Bifacial convergent scraper

1

1

Bifacial oval scraper

2

3

5

Bifacial convex scraper

1

1

Total

65

14

8

4

1

92

7The most common techno-type is that of bifaces with convergent lateral cutting edges and a pointed apex (TLCAP, n=65) (figures 2a-3a). The pieces within this type display variation in terms of outline, cross section, morphology of lateral cutting-edges (rectilinear, convex, irregular or denticulate) and in term s of the cross section and angle of the apex. These have been distinguished from pieces with convergent lateral cutting edges and a convex non-pointed apex (TLCAC, n=8) (figures 2b, 4a).

8The non-pointed pieces with a distal edge that is continuation of the lateral edges were divided into two groups:

  • bifaces with lateral convergent or convex cutting edges and an oblique distal cutting edges (TLCTDO, n=14) (figure 3b);

  • bifaces with lateral convergent or convex cutting edges and a transverse distal cutting edge (TLCTDT, n=4) (figure 4b).

Figure 3

Figure 3

a: Biface with an asymmetric cross section, convergent lateral cutting edge and an pointed apex (TLCAP) ; b: biface with a symmetric cross section and a distal oblique cutting edge (TLCTDO)

Photographs: M. Brenet

9The pieces were also compared to the classical bifacial types for the late Middle Palaeolithic (Bordes. 1988); cordiform bifaces were the most numerous (n=52) followed by triangular bifaces (n=14) and oval bifaces (n=8). It must be noted that nine of the pieces are not typologically bifaces but bifacial side scrapers or Mousterian points (table 4, figure 4a); such is the case of the only piece with convex cutting edge (TC), which is typologically a bifacial convex side scraper.

Techno-types and cross sections of the pieces

10Amongst the largest group of pieces – that of bifaces with convergent and pointed cutting edges (TLCAP) – pieces that are asymmetrical in cross section are the most prevalent (49 of 65). This is also true for the bifaces with convergent cutting edges and convex apical cutting edges (TLCAC; 6 of 8). For the bifaces with oblique distal cutting edge (TLCTDO), there is an equal number of symmetrical and asymmetrical pieces (7 and 7), while three out of four pieces with transverse cutting edge (TLCTDT) are biconvex in cross section (table 5).

Figure 4 - Bifacial scraper with a convex apex, made on a flake in flint from Charente (TLCAC) ; biface with a transverse distal cutting edge made on a flake in flint from Bergerac region (TLCTAT)

Figure 4 - Bifacial scraper with a convex apex, made on a flake in flint from Charente (TLCAC) ; biface with a transverse distal cutting edge made on a flake in flint from Bergerac region (TLCTAT)

Photographs a: E. Claud ; b: M. Brenet

Table 5 - Biface cross sections according to their techno-types

 

Volumetric form

 

Biconvex

Convex / planoconvex

Convex / plane

Total

Lateral convergent cutting edges and pointed apices

16

30

19

65

Lateral convergent cutting edges and convex apices

2

2

4

8

Lateral convergent or convex cutting edges and oblique distal cutting edge

7

2

5

14

Lateral convergent or convex cutting edges and transverse distal cutting edge

3

1

4

Convex cutting edge

1

1

Total

28

34

30

92

Techno-types and use

11Ten bifaces and three bifacial side scrapers of the 92 experimental pieces were not used. The 79 pieces that were used were primarily employed in woodworking (n=34) and various cutting activities in butchery (n=20), while eleven pieces were used in the transformation of animal materials (hide, bone, and antler), three were used to cut herbaceous plants, and four were used to dig in a clay-sand soil; finally, two bifacial points were used experimentally as hunting projectiles, and five bifaces (with or without wrapping) were transported in a sack. The numbers presented here are slightly different than those presented in Part I, chapter 2.10 because they are based on the pieces as a whole, while the numbers in chapter 2.10 are based on active zones, of which some pieces have more than one.

1261 of the 65 pointed bifaces (TLCAP) were used, mostly in woodworking (28) and butchery (14) (table 6).

Table 6 - Practised activities according to the biface techno-types

 

Simplified techno-type

 

TLCAP

TLCTAC

TLCDO

TLCTDT

TC

Total

Woodworking

28

2

2

2

34

Butchery

14

1

3

2

20

Hide working

6

1

7

Bone working

3

3

Antler working

1

1

Cutting herbaceous plants

2

1

3

Projectile use

2

2

Digging soil

2

1

1

4

Transport

3

2

5

Not used

4

3

6

13

Total

65

8

14

4

1

92

Hafting of the pieces

13Over the course of their use, only 14 pieces were used with a wooden handle (n=7) or a wrap made of strips of hide or plant fibers (n=7), the 65 others were held in hand (table 7, figure 5). It must be noted that nine of the handles or wraps were applied to bifaces that had been used to strike wood.

Table 7 - Prehension mode of bifaces during use, according to activities

 

In a wrap

Hafted

Bare hand

Total

Woodworking

5

4

25

34

Butchery

1

19

20

Hide working

7

7

Bone working

1

2

3

Antler working

1

1

Cutting of herbaceous plants

1

2

3

Projectile use

2

0

2

Digging soil

4

4

Transport

5

5

Total

7

7

65

79

Duration of use of the pieces

14With regard to the duration of use of the pieces, in the case of the two most treated materials – wood and meat – the bifaces were used for an average of 46 minutes each in butchery, compared to an average of 37 minutes per tool in woodworking (table 8). Use-time varied for the other materials worked (table 8):

  • cutting herbaceous plants, average of 47 minutes;

  • hide working, average of 33 minutes;

  • antler working, 30 minutes for a single biface;

  • digging soil, an average of 26 minutes;

  • bone working, an average of 13 minutes.

15These durations, which were generally adequate for the completion of the respective tasks (except in the case of the working osseous materials, to which the cutting edges of the bifaces proved ill‑suited) are very different from the durations of experimental transport and propulsion. For the pieces used as projectiles, the experiments terminated as soon as the point penetrated the animal, which was achieved with one shot for the first piece and with two shots for the second, the transport-times in the sack were around 6 h 20 min per piece (table 8).

Figure 5

Figure 5

Hafted biface (a) and biface wrapped in a vegetal sheath (b), used for chopping green wood (a) and scraping dry wood (b)

Photographs: E. Claud

Table 8 - Number of bifaces used for each activity, and experiment durations

 

Number of pieces

Average duration of use (min.)

Cumulative durations of use (min)

Woodworking

34

3 685

1253

Butchery

20

4 568

868

Hide working

7

3 286

230

Bone working

3

1 333

40

Antler working

1

30

30

Cutting of herbaceous plants

3

4 667

140

Projectile use

2

15

3

Digging soil

4

2 625

105

Transport

5

379

1895

Total

79

4564

Dimensions of the pieces

16The dimensions of the pieces are variable, ranging from 50 to 158 mm in length, from 38.5 to 101.9 mm for width, and between 9.8 mm and 39.8 mm in thickness. The majority of the pieces (69 of 92) fall between 80 and 120 mm in length. With regard to mass, this variable shows the greatest diversity, from the smallest pieces at 28 and 32 g, used as projectiles, to the bifaces weighing more than 350 g that were hafted for woodworking (table 9, figures 6‑7).

17The pieces with the greatest average volume are those used in butchery (104 mm in length and weighing 160 g on average) and in woodworking (99 mm in length and weighing 134 g on average). The two points used as projectiles were the smallest (62 mm and 29.8 g on average). The other pieces, used to work bone or hide, cut herbaceous plants, dig soil, or test the effects of transport are of average lengths ranging from 90.2 to 99.8 mm and of average mass ranging from 88 to 99.6 g (table 9). The sole piece used to work antler measured 104 mm in length and weighed 98 g.

Table 9 - Average dimensions and masses of bifaces according to the praticed activities

 

Number of pieces

Average length (mm)

Average width (mm)

Average thickness (mm)

Average masses (g)

Woodworking

34

991

646

201

1 342

Butchery

20

1 037

699

228

1 595

Hide working

7

975

585

175

984

Bone working

3

902

575

182

883

Antler working

1

104

593

184

98

Cutting of herbaceous plants

3

911

57

182

918

Projectile use

2

617

458

104

298

Digging soil

4

916

604

161

973

Transport

5

998

601

177

996

Total

79

Figures 6 - Lengths, widths and thicknesses of 92 experimental bifaces viewed in graphs

Figures 6 - Lengths, widths and thicknesses of 92 experimental bifaces viewed in graphs

Angles of the cutting edges

18The average edge angle was calculated with a goniometre for four zones on each piece:

  • on the basal edge (three measurements);

  • on the two lateral cutting edges at the apical third of the piece (two to three measurements);

  • at the point or distal cutting edge (two to three measurements).

19For all techno-types, the edge angles of the pieces decrease regularly from the bases to the cutting edges and then the apices.

Figure 7- Lengths, widths and masses of 92 experimental bifaces viewed in graphs

Figure 7- Lengths, widths and masses of 92 experimental bifaces viewed in graphs

20The pieces with convergent pointed cutting edges or convex apices (TLCAP and TLCAC) possess edge angles and cutting edge angles that are on average very narrow: 62° to 63° on the basal edge, 42° on the lateral cutting edges and 35° to 37° at the apices.

21The pieces with distal oblique cutting edges (TLCDO) have wider average edge angles than the preceding group on all edges: 68.4° on the basal edge. 46° to 46.4° on the lateral cutting edges. and 42.5° at on the apical cutting edge.

22Finally, the pieces with transverse distal cutting edges (TLCTDT) present even wider average edge angles on the bases and lateral edges – 79.5° to 53° – while the average angle of the transverse cutting edges was similar to that of the pointed pieces: 35.5° (table 10).

23Within each activity, the angles of the lateral and distal or apical cutting edges of the pieces are relatively varied. If we exclude the eleven experiments of projectiles, digging, and transport, the most acute lateral and distal or apical cutting edges (from 41.7° to 42.6° and from 34.9° to 35°) were preferentially used for butchery and hide working (table 11). It is worth noting that the average of 36.6° for the distal sections of the 34 pieces used on wood would not be taken into account because the distal cutting edges of 10 of these pieces were either too irregular to be measured or were fractured during use.

24Finally, we note that the experiments in working bone and antler were conducted with bifaces whose lateral and distal or apical cutting edges were among the widest, with averages between 43° and 46.3°, but the angles were measured after use. and it is possible that the measured angle was augmented by the scarring of the edges related to use on these particularly hard materials (table 11).

Table 10 - Average angles of bifaces cutting edges according to techno-types

 

Code

Average angles

 

base

left side

right side

distal part

Lateral convergent cutting edges and apical point

TLCAP

62

424

438

354

Lateral convergent cutting edges and convex apex

TLCAC

629

421

433

368

Lateral convergent cutting edges and oblique distal edge

TLCTDO

684

464

46

425

Lateral convergent cutting edges and transverse distal edge

TLCTDT

795

533

53

355

Table 11 - Average angles of bifaces cutting edges according to the practised activities

 

Average angle

 

left side

right side

lateral edges

distal part

Projectile use

395

40

398

28

Digging soil

393

415

404

36

Transport

404

412

408

37

Butchery

428

407

417

349

Hide working

447

404

426

35

Woodworking

44

476

458

366

Cutting of herbaceous plants

403

45

427

38

Antler working

42

44

43

43

Bone working

46

467

463

43

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Table des illustrations

Titre Figure 1 - Experimental manufacturing of flint bifaces; on the left with an organic hammer (experimenter: S. Maury), on the right with a mineral hammerstone
Crédits Experimenter: M. Brenet
URL http://journals.openedition.org/palethnologie/docannexe/image/4257/img-1.jpg
Fichier image/jpeg, 117k
Titre Figure 2 - Bifaces with a convex distal edge (TLCAC)
Légende a: biface on flake in "Grain de mil" flint, from Charente region, with convergent lateral cutting edges; b: biface on flake in Maastrichtien flint, from Bergerac region
Crédits Photographs: É. Claud
URL http://journals.openedition.org/palethnologie/docannexe/image/4257/img-2.jpg
Fichier image/jpeg, 51k
Titre Figure 3
Légende a: Biface with an asymmetric cross section, convergent lateral cutting edge and an pointed apex (TLCAP) ; b: biface with a symmetric cross section and a distal oblique cutting edge (TLCTDO)
Crédits Photographs: M. Brenet
URL http://journals.openedition.org/palethnologie/docannexe/image/4257/img-3.jpg
Fichier image/jpeg, 37k
Titre Figure 4 - Bifacial scraper with a convex apex, made on a flake in flint from Charente (TLCAC) ; biface with a transverse distal cutting edge made on a flake in flint from Bergerac region (TLCTAT)
Crédits Photographs a: E. Claud ; b: M. Brenet
URL http://journals.openedition.org/palethnologie/docannexe/image/4257/img-4.jpg
Fichier image/jpeg, 59k
Titre Figure 5
Légende Hafted biface (a) and biface wrapped in a vegetal sheath (b), used for chopping green wood (a) and scraping dry wood (b)
Crédits Photographs: E. Claud
URL http://journals.openedition.org/palethnologie/docannexe/image/4257/img-5.jpg
Fichier image/jpeg, 57k
Titre Figures 6 - Lengths, widths and thicknesses of 92 experimental bifaces viewed in graphs
URL http://journals.openedition.org/palethnologie/docannexe/image/4257/img-6.jpg
Fichier image/jpeg, 43k
Titre Figure 7- Lengths, widths and masses of 92 experimental bifaces viewed in graphs
URL http://journals.openedition.org/palethnologie/docannexe/image/4257/img-7.jpg
Fichier image/jpeg, 47k
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Référence électronique

Michel Brenet, « Annex 3 - Inventory of bifacial flint tools used in the experiments », Palethnologie [En ligne], 10 | 2019, mis en ligne le 01 novembre 2019, consulté le 16 décembre 2019. URL : http://journals.openedition.org/palethnologie/4257

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