With regard to the external shaping of the perforated stone axes not much need be said. They appear to have been in some |53| cases wrought into shape by means of a pick or chisel, and subsequently ground; in other cases to have been fashioned almost exclusively by grinding. In some of the axe-hammers made of compact quartzite, the form of the pebble from which they have been made has evidently given the general contour, in the same manner as has been observed on some fibrolite hatchets, which have been made by sawing a flat pebble in two longitudinally, and then sharpening the end, or ends, the rest of the surface being left unaltered in form. This is also the case with some stone hatchets, to form which a suitable pebble has been selected, and one end ground to an edge. Such is a general review of the more usual processes adopted in the manufacture of stone implements in prehistoric times, which I have thought it best should precede the account of the implements themselves. I can hardly quit the subject without just mentioning that here, as elsewhere, we find traces of improvement and progress, both in adapting forms to the ends they had to subserve, and in the manner of treating the stubborn materials of which these implements were made. Such progress may not have been, and probably was not, uniform, even in any one country; and, indeed, there are breaks in the chronology of stone implements which it is hard to fill up; but any one comparing, for instance, the exquisitely made axe-hammers and delicately chipped flint arrow-heads of the Bronze Age, with the rude implements of the Palæolithic Period—neatly chipped as some of these latter are—cannot but perceive the advances that had been made in skill, and in adaptation of means to ends. If, for the sake of illustration, we divide the lapse of time embraced between these two extremes into four Periods, it appears— 1. That in the Palæolithic, River-gravel, or Drift Period, implements were fashioned by chipping only, and not ground or polished. The material used in Europe was, moreover, as far as at present known, mainly flint, chert, or quartzite. 2. That in the Reindeer or Cavern Period of Central France, though grinding was almost if not quite unused, except in finishing bone instruments, yet greater skill in flaking flint and in working up flakes into serviceable tools was exhibited. In some places, as at Laugerie-haute, surface-chipping is found on the flint arrow-heads, and cup-shaped recesses have been worked in other hard stones than flint, though no other stones have been used for cutting purposes. |54| 3. That in the Neolithic or Surface Stone Period of Western Europe, other materials besides flint were largely used for the manufacture of hatchets; grinding at the edge and on the surface was generally practised, and the art of flaking flint by pressure from the edge was probably known. The stone axes, at least in Britain, were rarely perforated.