It is not, however, proven that the Mound Builders were the sole workers of these ancient mines. It is known that the Indians mined for flint. Some of the excavations for this purpose, in what is known as Flint Ridge, in Muskingum County, Ohio, are as marked as the traces of ancient mining in Michigan. Similar appearances are recorded in Missouri. As copper was in demand among the Indians, and as it is probable that they obtained much of it from the North, they may have continued to work the ancient copper mines until comparatively recent times. Mr. Lapham believes that the progenitors of the Indian tribes found dwelling in the regions near these mines, carried on mining operations there. Dr. Rau thinks it probable that small bands of various Northern tribes made periodical excursions to the locality, returning to their homes when they had supplied themselves with sufficient quantities of the much-desired metal. The fact that many of the modern Indian tribes knew nothing about these mines is not of much weight, when we reflect how easily a barbarian people forget events, even those of a striking nature. We are apt to judge the culture of a people by the skill they display in works of arts. The article on which the Mound Builder lavished most of his skill was the pipe. This would show that with them, as with the modern Indians, the use of the pipe was largely interwoven with their civil and religious observances. In making war and in concluding peace, it probably played a very important part. “To know the whole history of tobacco, of the custom of smoking, and of the origin of the pipe, would be to solve many of the most interesting problems of American ethnology.”91 The general decoration consisted in carving the bowl of the pipe into the shape of some animal or bird. In some instances we have carved representations of the human head. Such as these are of particular interest and value, as they are probably faithful representations of the features of the Mound Builders. This is a fine specimen found in one of the altar mounds in Ohio. The method of wearing the hair is worthy of notice. The holes placed in a row encircling the forehead and coming down as low as the ears, were once filled with pearls. In some they still remained when found, though they had been burned in the fire. The lines upon the face obviously imitate the custom of tattooing the countenance. Sculptured Face and Face of a Female.