It is a well-known fact that the rattlesnake is the variety almost universally represented, and we find that these engravings on shell present no exception to this rule. From a very early date in mound exploration these gorgets have been brought to light, but the coiled serpent engraved upon their concave surfaces is so highly conventionalized that it was not at once recognized. Professor Wyman appears to have been the first to point out the fact that the rattlesnake was represented; others have since made brief allusion to this fact. Two examples only have been illustrated; one by Professor Jones,[147] who regards it as being without intelligent design, and the other by Dr. Rau,[148] who does not suggest an interpretation. Among the thirty or forty specimens that I have examined, the engraving of the serpent is, with one exception, placed upon the concave side of the disk, which is, as usual, cut from the most distended part of the _Busycon perversum_, or some similar shell. The great uniformity of these designs is a matter of much surprise. At the same time, however, there is no exact duplication; there are always differences in position, detail, or number of parts. The serpent is always coiled, the head occupying the center of the disk. With a very few exceptions the coil is sinistral. The head is so placed that when the gorget is suspended it has an erect position, the mouth opening toward the right hand. As at first glance it will be somewhat difficult for the reader to make out clearly the figure of the serpent, even with the well defined lines of the drawing before him, I will present the description pretty much in the order in which the design revealed itself to me in my first attempt to decipher it. The saucer-like disks are almost circular, the upper edge being mostly somewhat straightened--the result of the natural limit of the body of the shell above. All are ground down to a fairly uniform thickness of from one-eighth to one-fourth of an inch. The edges are evenly rounded and smooth. Two small holes for suspension occur near the rim of the straighter edge, and generally on or near the outline of the engraved design, which covers the middle portion of the plate. The diameter ranges from one to six inches. To one who examines this design for the first time it seems a most inexplicable puzzle; a meaningless grouping of curved and straight lines, dots and perforations. We notice, however, a remarkable similarity in the designs, the idea being radically the same in all specimens, and the conclusion is soon reached that there is nothing haphazard in the arrangements of the parts and that every line must have its place and purpose. The design is in all cases inclosed by two parallel border lines, leaving a plain belt from one-fourth to three-fourths of an inch in width around the edge of the disk. All simple lines are firmly traced, although somewhat scratchy, and are seldom more than one-twentieth of an inch in width or depth.