Traces of in addition to this such stones show traces of use, the edges being worn in such a manner as would naturally arise from their employment as cutting, scraping, or breaking instruments, then the proba bility that they were made and used for such purposes by intelligent crea tures is further strengthened.
Ejects of effects of fire on stones are altogether different from those of any other agency, and when we perceive that fragments otherwise of doubtful origin have been subjected to igneous action which geological surroundings do not explain, we can almost positively assert that they betray the presence of man, in all times the only fire maker.
Primary and Secondary Chipping.—Finally, the technical method of preparing the earliest stone implements is characteristic. It was by a process of fracture, known as primary and chipping. By the former the stone was broken off from its original matrix, and by a few well-directed blows brought approximately into the shape desired. In many stones which break with a conchoidal fracture, as flint, chalcedony, and jasper, when a fragment is detached by a sharp blow a semiglobular prominence is produced immediately below the point of impingement. This is called the bulb of percussion, and is almost characteristic of a blow aimed by an intelligent hand at a particular spot. The plane of percus sion is the comparatively level surface upon which the blow is struck, and the conchoia' of percussion is the conchoidal surface of the stone produced by the force applied. A close study of these three peculiarities reveals differences between them, when they are produced by natural and when by intelligent and directed force, sufficient to constitute them testimony of a high order to the presence or absence of intelligent design.
chipping, called by the French Manche, is the series of light fractures at the edge of a stone produced in order to obtain a sym metrical shape and a finer cutting edge. When the secondary chipping is such that these results are secured, it is considered proof positive of the handiwork of man, for we cannot conceive that the chance work of natural forces would combine to this end, any more than that if we threw down promiscuously the separate letters of the alphabet they should arrange themselves into a verse of poetry. The highest style of secondary chipping is when the flakes thrown off were long and narrow and pre cisely of the same width and thickness. This is called parallel chipping, and is seen only in the finest specimens of the art of the Stone Age, espe cially in relics from Denmark.
The .1fos1 Ancient Specimens of Human Art.—What are believed by many to be the most ancient remains of human industry yet discovered in the Eastern Hemisphere are certain worked flints from a deposit near Thenay, in Central France (pl. I, figs. I , 2), department of Loir-et-Cher, and similar specimens in silex from the alluviums of the river Tagus in Portugal (fig. 3).
The former were brought to the notice of men of science in 1S67 by the Abbe Bourgeois. They consisted of shaped stones with considerable uniformity of size and appearance, some showing marks of exposure to fire and others rough secondary chippings. Several competent geolo gists, who examined with great care the deposit from which they were obtained, pronounced it to be of the middle or late Tertiary.
The chipped siliceous fragments from the ancient bed of the Tagus near Lisbon were discovered by M. Ribeiro, and this stratum also has been declared by able judges to be of Tertiary Age. The supposed imple ments have a similarity of shape among themselves, but in no instances do they present secondary chipping or traces of the action of fire.
While several continental archaeologists of repute not only accept these remains as the work of man—or of the anthropoid which was his precursor and ancestor—but also place them in the remote geologic age mentioned, thus tracing man's ancestry in France and the Iberian Penin sula back to the middle Tertiary, the more cautious English writers, notably Professor Dawkins, have refused their assent to these con clusions.
These 'authorities point out the inherent improbability of the sur vival of the species through so long a duration of time; moreover, the specimens from Portugal rest so equivocally between natural and arti ficial shapes that they leave doubts in minds quite willing to .accept them; and although this can scarcely be said of the Thenay flints, the age of the deposit where these occur has not been settled beyond dis pute. While, therefore, M. de Mortillet and with him most of the French archaeologists have declared themselves of the opinion that a fire-making, tool-using animal flourished on French soil far back in the Pliocene, if not in the Miocene, such an interpretation of the facts has not been accepted by other antiquaries. The shape and character of these much discussed relics may be seen in the illustrations on Plate t (figs. I, 2, 3, the last from a supposed Tertiary deposit near Lisbon).