The Chellean pick was made by striking a round or oval nodule of flint with another stone and knocking off pieces. Most of the detached flakes were large, as shown by the surfaces from which they came off; perhaps most of the chips averaged a square inch. Anything like fine work or evenness of outline was therefore out of question. One can imagine that many tools were spoiled, or broken in two, by the knocks to which they were subjected in their manufacture. The flakes struck off fell to the ground and were discarded. If the workman was sufficiently skilful, and luck stayed with him, he would before long be holding the sort of implement that has been described. Not more than a few dozen strokes of the hammer stone would be required to produce it.
Fig. 18. Stone implements illustrating the principal types of Palæolithic chipping. a, Chellean pick, a roughly flaked core; b, Mousterian scraper, a flake with retouched edge; c, Solutrean blade, evened by retouching over its entire surface; d, Magdalenian knife, a flake detached at one blow. For comparison, e, an obsidian knife or razor from Mexico, made by the same process as d.
Some attempt has been made to distinguish variant forms of Chellean tools, such as scrapers, planers, and knives. But some of these identifications of particular types are uncertain, and at best, the differences between the types are slight. It may be said with approximate accuracy that the long Chellean period possessed only the one tool; that this is the first definitely shaped tool known to have been made by human hands; and that it is therefore the concrete evidence of the first stage of that long development which we call civilization.[11]
Acheulean.—The Acheulean period brings to light a growing specialization of forms and some new types. Rude scrapers, knives, borers, can be distinguished. The flakes struck off are finer than in the Chellean and the general workmanship averages higher; but through the whole of the Acheulean there is no new process. The Chellean methods of manufacture are improved without an invention being added to them.
Mousterian.—In the Mousterian period a retrogression would at first sight seem to have occurred. Tools become smaller, less regular in outline, and are worked on one side only. The whole Mousterian period scarcely presents a single new type of implement of such all-around serviceability as the Chellean pick. Nevertheless the degeneration is only in the appearance of the implements. Actually they are made by a new process, which is more advanced than that followed in the Chellean and Acheulean. In these earlier periods flakes were struck off until the kernel of stone that remained was of the shape desired for the tool. The Mousterian technique is distinguished by using the flake instead of the core. This is the cause of Mousterian tools being generally smaller and lighter.
Secondly, when the flake dulled by use, its edge was renewed by fine chipping. The pieces detached in this secondary chipping are so small that it would have been difficult to knock them off and maintain any regularity of edge, for to detach a chip by a blow means violent contact. If the blow is a bit feeble, the chip that comes off is too small. If the artifact is struck too hard, too large a chip flies off and the implement is ruined. Fine chips are better worked off by pressure than by impact. A point is laid upon the surface near the edge. When this point is pressed down at the proper angle and with proper firmness, a scale flies off. With some practice the scales can be detached almost equal in size. The point may be of softer material than the stone. It is in the nature of flint, and of all stones that approach glass in their structure, that they break easily under pressure in definite planes or surfaces. Modern tribes that still work flint generally employ as a pressing tool a piece of bone or horn which comes to a somewhat rounded point. This is usually attached to the end of a stick, to enable a better grip of the working tool, the butt end being clamped under the elbow. A tool of the same sort may have been employed in the Palæolithic. The process of detaching the scales or secondary flakes by pressure is known as “retouching.” Retouching allows finer control than strokes delivered with a stone. The result is that Mousterian implements, when at their best, possess truer edges, and also greater variety of forms adapted to particular uses, than those of preceding ages ([Fig. 18], b).
In spite of their insignificant appearance, Mousterian tools accordingly show advance in two points. First, the flake is used. Secondly, two processes instead of one are followed; the knocking off of the flake followed by its retouching.