In discussing celts, gouges, and adzes, I said almost nothing about the material out of which these were manufactured. Fortunately, our friends the geologists and mineralogists have devoted some time to this subject. Professor George L. Collie, Dean of Beloit College and Curator of the Logan Museum, prepared a paper which is published in the _Wisconsin Archeologist_, June-September, 1908. The title of this is “Aboriginal Discrimination in the Selection of Materials for Tools.” I reproduce sections of it here, as it describes the various stones selected by aboriginal man. [Illustration: FIG. 249. (S. 1–6.) In this figure I have shown five of the Connecticut axes from A. E. Kilbourne’s collection. So far as type is concerned these might have been found in Pennsylvania, Connecticut, or eastern Canada, for they are typically New England. The ones at the right and the left show scarcely any traces of chipping, but the centre ones have been chipped and later ground and polished. These are of Class “A,” the groove entirely encircling the specimen, yet the groove on the surfaces is very slight, but pronounced and deep at the edges. ] I would call attention to Professor Collie’s able paper, because he comments not only on these implements from the point of view of a geologist, but also adds no little to our sum of archæological knowledge:— “Under this head it is my desire to discuss some evidences that the American aborigine exercised deliberate choice when he picked out materials for the manufacture of artifacts. “Stone had to be shaped by some one or more of five processes as is well known. These manual arts, as stated by Holmes, are as follows: (1) Fracturing by splitting, breaking, flaking; (2) bruising by battering, pecking, bushing; (3) abrading by grinding, rubbing, polishing; (4) incising by cutting, piercing, drilling; (5) modeling by stamping or hammering. These shaping arts called for different types of material in several instances and this necessitated choice on the worker’s part at the outset. He not only needed to know what kind of an artifact he was to make, but which of the several processes he was to employ before he finally settled upon the material he would use. Man learned by slow degrees and by experience the nature of rock properties. He learned to distinguish between different types of rocks much as a modern geologist does in the field by taking account of two features, namely: (1) The mineralogical composition; (2) the texture of the rock. I do not mean to imply that early man was absolutely guided by the quality of the rock; other factors entered into the choice, but rock character was always a prominent factor. [Illustration: