TOOLS MAKYTH MAN—OAKLEY 435 
flaking was of the high-angled type characteristic of the work of 
nature. 
Out of 1,800 measurements of platform-scar angles in 18 different 
human industries, Barnes found less than 18 percent over 90°; but in 
flaked flints from Eocene deposits over 54 percent of the flake scars 
proved to have angles over 90°, while among flaked flints from the 
Crag formations over 62 percent of the flake scars are more than 90°. 
Professor Barnes concluded: “The high proportion of high-angle 
scars in the Tertiary flints contrasts sharply with the paucity of high 
angles in the human industries, and suggests that the Tertiary flaking 
B. Natural Fractures. 
Seren re i 
“23 ¢€ SF 83 F 6 9G M4 2 KB HI 6 
C. Human Work 
Fic. 1.—Percentages of obtuse platform-scar angles found in: 4, eoliths in flint, including 
Sub-Crag (J and 3); B, Naturally fractured stones, including flints crushed under cart 
wheels (3) or broken in foundering of deposits (4), and chipped hard rocks in moraines (7); 
C, human flint industries, mainly early, including Abbevillian (2), Acheulian (5-8, /2), 
Tayacian (9, 10), and Mousterian (J3). (After A. S. Barnes, by courtesy of the editor 
of American Anthropologist.) 
was due to soil movements under pressure arising from solifluxion, 
foundering, or ice action” (Barnes, 1943). 
Warren reached a similar conclusion after prolonged study of the 
character of the Crag flaking (1948) and, having reviewed the geo- 
logical evidence, concluded that the Stone Bed and Bone Bed did not 
accumulate as beach deposits, but on a submarine fioor, “which cannot 
reasonably be supposed to have been available for human habitation.” 
As about 50 percent of stones in some parts of the Stone Bed are flaked, 
and as the deposit occupies several hundred square miles, a widespread 
natural cause was most probably responsible for them. The striations 
and bruisings which many of the Sub-Crag flints show are consistent 
with Warren’s idea that the chief cause of the flaking was the ground- 
