Most persons familiar with the handiwork of prehistoric man agree that when man began to use stone implements he selected such natural or water-worn stones as required little work to make of them effective weapons. Along the shores of a river or lake, about the foot of a cliff, or on stony ground, he was apt to find fragments of rock broken by natural agencies. Some of these had sharp edges, and it is quite likely that his first knives and scrapers were flakes or spalls which served him as crude implements. This theory has been worked out at length in several publications and need not be repeated here. The chipped implements themselves evince all kinds of workmanship; some are well made, others appear to be either childish attempts or the work of artisans unskilled in flint-chipping. Some are finished, others are unfinished. Many an implement is open to question as to whether it is a rude complicated form, or an unfinished object, and numbers of these rude forms may be exceedingly old so far as we know; again some of the finer implements are doubtless old. [Illustration: FIG. 67. (S. 1–2.) Lance-heads: obsidian, from California. H. P. Hamilton collection. ] In classifying flint implements it is generally conceded that the oval form is the more simple, and Dr. Wilson’s classification begins with these. While the Committee accepted, as stated previously, his scheme, together with that of Mr. Fowke, yet it seems to me that a careful study of the oval forms convinces one that many of them are unfinished, and may have been intended for implements that would on completion be placed in another class. Also, that many of the oval and circular forms are thick and rough and do not appear to be implements. However, in the classification it is best not to consider whether these objects are finished or unfinished or for what purpose they were intended, but in my descriptions I have separated those which appear to be implements from those that do not. I have presented original specimens rather than tracings as did Dr. Wilson. The ordinary form of knife and the simplest form of projectile point is shown in Fig. 44, collection of Mr. D. N. Kern. These specimens were found in Lehigh County, Pennsylvania, and are made of yellow jasper, except the central one, which appears to be Flint Ridge stone. I have selected this group as typical. They represent the first stage of complete work after the turtleback or discs have been scaled to a proper size. Some of these are knives, some may have been arrow-points, all look old, and most of them fall in Class 1 B, although none of the bases are concave. Fig. 45 represents two rough knives which are just beyond the stage of turtlebacks. Fig. 46 is taken from a large flake of flint detached while chipping spades and other implements of unusual size on the site of the Indian Territory quarries. This flake has been edged and used as a knife.