I have hitherto been treating of the production of flint flakes for various purposes. In such cases the flakes are everything, and the resulting core, or nucleus, mere refuse. In the manufacture of celts, or hatchets, the reverse is the case, the flakes are the refuse (though, of course, they might occasionally be utilized) and the resulting block is the main object sought. To produce this, however, much the same process appears to have been adopted, at all events where flint was the material employed. The hatchets seem to have been rough-hewn by detaching a succession of flakes, chips, or splinters, from a block of flint, by means of a hammer-stone, and these rough-hewn implements were subsequently worked into a more finished form by detaching smaller splinters, also probably by means of a hammer, previously to their being ground or polished, if they were destined to be finished in such a manner. In most cases, one face of the hatchet was first roughed out, and then by a series of blows, given at proper intervals, along the margin of that face the general shape was given and the other face chipped out. This is proved by the fact that in most of the |32| roughly-chipped hatchets found in Britain, the depressions of the bulbs of percussion of the flakes struck off occur in a perfect state only on one face, having been partly removed on the other face by the subsequent chipping. There are, however, exceptions to this rule, and more especially among the implements found in our ancient river gravels. In some cases (see _postea_, Fig. 12) the cutting edge has been formed by the intersection of two convex lines of fracture giving a curved and sharp outline, and the body of the hatchet has been subsequently made to suit the edge. The same is the case with the hatchets from the Danish kjökken-möddings and coast-finds, though the intersecting facets are at a higher angle, and the resulting edge straighter, than in the specimens which I have mentioned. The edge is also, like that of a mortising chisel, at the extremity of a flat face, and not in the centre of the blade. The cutting edge has, however, in most of the so-called celts of the ordinary form, been fashioned by chipping subsequent to the roughing out of the hatchet; and even in the case of polished hatchets, the edge when damaged was frequently re-chipped into form before being ground afresh.