Table 1.

Percentage presence of elongate Acheulean bifaces with breadth/length (B/L) ratio 0.50 or less. (Columns: approximate age in millions of years; total sample number; number of specimens with ≤ 0.50; percentage of the elongated specimens; B/L ratio for all bifaces; mean length of all bifaces; mean length of bifaces with B/L ≤ 0.50. Measurements: author, except Kalambo Falls (D. Roe and J. D. Clark); Peninj (I. de la Torre). Principal site sources: San Isidro/Pinedo (Spain) [94] Kapthurin (Kenya) [75,76,95] Kalambo Falls (Zambia) [49] STIC (Morocco) [96] Kilombe (Kenya) [97] Kariandusi (Kenya) [98] Cornelia (S. Africa) [99] Peninj (Tanzania) [100,101].)

	approx. age (Ma)	N (all)	N with B/L ≤ 0.50	% with B/L ≤ 0.50	B/L all	mean length all	mean length with B/L ≤ 0.50
San Isidro	0.3	45	15	33	0.55 ± 0.07	148	164
Pinedo	0.3	58	4	7	0.61 ± 0.09	118	148
Kapthurin	0.3	35	2	6	0.68 ± 0.11	147	202
Kalambo Falls B4	0.4	25	4	16	0.61 ± 0.10	170	208
Kalambo Falls A6	0.4	47	8	17	0.58 ± 0.07	169	163
STIC	0.7	299	52	17	0.57 ± 0.09	161	178
Kilombe	1.0	627	35	6	0.60 ± 0.07	146	167
Kilombe AS	1.0	21	5	24	0.56 ± 0.07	138	148
Kariandusi	1.0	126	20	16	0.58 ± 0.06	164	186
Cornelia	1.0	12	6	50	0.54 ± 0.06	201	221
Peninj BAY	1.4	18	6	33	0.54 ± 0.09	179	199
Peninj MUG	1.4	77	20	26	0.59 ± 0.09	158	182