the central portion, existed when the country was first settled by the whites, but from various causes it has been reduced until it now is all of one level. This, while the largest, is only one of several hundred such places.” Similar operations were employed in Indian Territory and elsewhere. In the quarries of Little River, Tennessee, the flint occurred in nodular form in limestone ledges. It was easier for the natives to burn the limestone and remove the nodules than to quarry in the flint layers of Flint Ridge. Fig. 1 shows the nodules outcropping in two layers in the limestone ledge. Mr. D. N. Kern, of Allentown, Pennsylvania, informs me that there are fully two hundred pits of various sizes where the natives quarried material, within some miles of his home. Professor Wm. H. Holmes published in the 15th _Annual Report_ of the Bureau of Ethnology a comprehensive paper entitled “Stone Implements of the Potomac-Chesapeake Tide-Water Province.” This paper embodies the observations for a number of years on the archæology of Virginia, Maryland, and the District of Columbia. The description of the quarries along Piney Branch, a small tributary of the Potomac, in the District of Columbia, in this volume is complete, and I wish to recommend to students and readers who wish to obtain a broad understanding of the subject a perusal of Professor Holmes’s paper. The entire genesis of implement making is ably presented. While other quarries have not been so carefully worked, and certainly not described in detail, the method employed by the prehistoric peoples at the Piney Branch quarry, and in the rhyolite sites further back in the hills on either side of the Potomac, may be taken as typical of aboriginal quarrying in the United States. That is, of quarrying in beds where boulders or nodules are embedded in clay or gravel or till. The boulder or nodule materials and the flint strata occurring in different formations were quarried by different methods. The Piney Branch quarries are an illustration of the separation of material from the general mass and composite of boulder and clay. It was easy to get at the material, but more difficult to fashion the implements, because quartzite, quartz, and argillite were harder to work than flint. At Flint Ridge, while quarrying was extremely difficult, the material once secured could be very easily fashioned. The planes of cleavage of flint, as all know, were very different from those of the boulders found at Piney Branch. [Illustration: FIG. 32. Flaking by pressure. Manner of holding as observed among many tribes by J. W. Powell and others. ] [Illustration: FIG. 33. Flaking by pressure, bone pincers being used. ]