There is a lesson to be drawn from the preponderance of these flint celts and axes over those of granite or limestone. Where flint is more common—as in the Ozarks—than other materials, aboriginal man modified his form of hatchet in accordance with the material at hand. It would be too hard for him to groove a flint axe. He, therefore, notched the sides of the rough blade or turtleback, and lashed it in the handle. If the blade got dull he scaled off a few flakes and restored the cutting edge. Flint axes made convenient and formidable implements and weapons. There was an abundance of surface flint in Indian Territory and Kansas, as well as quarry material. And the flint celt became widespread from a point about two hundred miles east of the Mississippi in Tennessee and Kentucky to southern Iowa and southern Indian Territory, three hundred miles west of the Mississippi. Outside of this belt flint celts are rare. Yet in widespread areas where flint abounds, celts and kindred implements of flint are not found. The range of the flint celts is from the rough implements to the highly developed spud-shaped polished flint celts found in Tennessee graves. [Illustration: FIG. 177. (S. 1–2.) More highly specialized notched implement, from the collection of W. H. Davis, Lowell, Ohio. Dark, bluish-gray flint. Found on the banks of the Muskingum River, near Marietta, Ohio, in 1887. ] These flint celts are usually rough, but frequently present a very high polish, indicating a long and continued use. Particularly is this polish noticed on the edges. The form of them does not vary as much as the forms of the celts in granite, limestone, sandstone, porphyry, or other materials. But flint celts may be divided into two classes, the oval form and the form with the sides somewhat square. I think the latter class represents the art of more skillful workmen. The specimens thus made are more nearly like the European type of square flint celts than are our other prehistoric implements. Flint axes form, of course, a separate division or class from the celts. [Illustration: FIG. 178. (S. 1–2.) Five flint celts from the collection of S. D. Mitchell, Ripon, Wisconsin. Such are found in Wisconsin as well as other parts of the country. ] [Illustration: FIG. 179. (S. 1–3.) Polished celts of flint. Upper row, adze-shaped; lower row, celt-shaped. From central and southern Kentucky. B. H. Young’s collection, Louisville, Kentucky. ] [Illustration: FIG. 180. (S. 1–2.) Ten flint celts of various types, Phillips Academy collection, Andover. These are of chert, jasper, and argillite, and were found in Kentucky, Arkansas, Missouri, and Iowa. They range from square celts to oval, although the cutting edge is usually at one end. ] [Illustration: FIG. 181. (S. 2–3.) Flint celt. Material: light-colored flint. Collection of M. L. Young, Pontiac, Illinois. Found in Massac County, Illinois, on the surface. ]