“With the onset of the discussions concerning the question of how the eoliths were produced, ” wrote Breuil (1910, p. 386), “I frequently thought that an examination of the broken flints at the base of the Bracheux sands of the Thanetian at Belle-Assise would yield some interesting observations.” Breuil gathered specimens over the course of three years, carefully observing patterns of breakage. “I always avoided using metal tools to extract the flints, and also took care to reject those that had been subjected to contact from the picks of the workers. It is somewhat easy, at the moment one extracts a flint, to examine its surfaces, to see if the fracturing has been produced recently, or if the breakage took place before the excavation. The surfaces of ancient fractures always have thin deposits of iron or manganese” (Breuil 1910, p. 386).
Breuil (1910, pp. 386–387) then stated: “Having noted, without any possibility of doubt, the presence of flints with fractures indicative of intentional work and retouching, and thus resembling what are called eoliths, I invited many persons to come and confirm the fact. Capitan, Cartailhac, and Obermaier were able, along with me, to collect these characteristic flint objects with their own hands. Mr. Commont, with whom I had the pleasure of making an inspection of the flint-bearing strata, also collected some specimens. Furthermore, Commont found flints with features resembling intentional work and retouching in various Eocene exposures in Picardy. The stratigraphic position of the discoveries was the same as at Belle-Assise.”
Breuil then described specimens that displayed retouching, bulbs of percussion, and striking platforms. Some showed regular bifacial flaking, typical of Late Paleolithic implements. Others had chipping confined to the side of the flake opposite the bulb of percussion, another characteristic of human work. But Breuil (1910, p. 388) warned: “If in our descriptions we use terminology that normally is applied to proper tools of human manufacture, that is nothing more than a convention, a manner of expression, and does not at all signify that we suppose for an instant we are dealing with ancient implements made by people of Eocene or pre-Eocene times.”
Breuil felt that human action could be ruled out with complete certainty because the flints were found in an Eocene formation. Like many other scientists, he could not imagine human beings existed in the Eocene, when the mammals known from fossils were, apparently, quite different from those of today. Breuil (1910, p. 406) wrote of “the absolute unlikelihood of the presence, before the deposit of the Bracheux sands or during their deposit, of an intelligent being, a worker of flint.”
But if human action were to be excluded, how, then, had the flint objects been produced? Searching for a natural explanation, Breuil (1910, pp. 387–388) wrote: “It is easy to observe that the flints have not been subjected to transport, for their sharpest edges remain intact. From among the processes that could have resulted in their fracture, one can therefore eliminate the mechanical action of water, either of oceans or rivers. Further examination of the fracturing gives evidence of a different kind of mechanical action, which was able to produce facets and impressions analogous to those produced by intentional human work, or by energetic localized force. A bulb of percussion, more or less clearly present, is often found at the point where a flake was taken off from the surface of the parent block. One can totally eliminate a thermal origin of the fractures, because fractures produced by heat, in the form of surface flaking or cracking of the entire flint block, are completely different.”
Breuil (1910, p. 403) then presented specimens that he believed shed a very clear light on the mode of production of the “pseudotools” he had reviewed: “They are pieces of flint which were flaked while in their positions in the interior of the beds, the fragments remaining in contact with each other. It is easy to see that these fragments present conchoidal fracturing, with the production of positive and negative bulbs of percussion” (Figure 3.20).
Figure 3.20. Henri Breuil (1910, p. 405) found examples of flakes removed from parent blocks of flint by geological pressure in an Eocene formation in Clermont (Oise), France. Such specimens, he believed, showed that eoliths were not made by human beings.