The arrow-heads, spear-heads, and knives of the prehistoric races have such likeness of form, style, and size that a line of division between the three is practically impossible. A small implement may be an arrow-head; a large one of the same type may be a spear-head, while either or both may have served as knives. The distinction might be better made if the shafts or handles remained; but these, together with the lashings and attachments, have decayed and disappeared, except when bitumen or gum has been employed.

An implement of this kind, whether large or small, with a light, long shaft, would be an arrow; the same with a heavy, long shaft would be a spear, while either of them with a shaft and lashing, but short instead of long, would be a knife or dagger. Indeed an implement of the latter class might be accidentally made through the breaking of the shaft of a spear or arrow; but none of these implements of the real prehistoric man have been found with their shafts or handles and lashing fastenings, and so we are driven to theory for their name and uses.

The classification of stone arrow-heads, spear-heads, and knives has been attempted by few archaeologists and with but slight success. No classification has as yet been generally adopted. Those heretofore attempted have been too complex, the divisions have been too close, and the distinctions not sufficiently broad to be popular. A classification of infinitesimal divisions, with slight differences, difficult to distinguish and still more difficult to remember, will never be satisfactory or acceptable.

I have attempted the following classification for these implements in the Department of Prehistoric Anthropology of the National Museum, believing it to be free from the foregoing objections, and yet to be broad enough to include practically all the implements of this kind made or used by prehistoric man.