At the right, in row I, are the slightly curved crescents or pick-like forms. More pronounced curves in these, as shown in row J, enable one to make a series ending in the L-shaped forms. In row K, the oval slate pebble is drilled through its long diameter, or through the short diameter, according to the fancy of the native, and the grain or strata of the stone. Some of the specimens exhibit slightly flaring sides and these become more pronounced until the “butterfly” form of problematical stones is apparent. The eighth specimen from the left toward the right in row K indicates how this stone may take another form. Row M to the left indicates small pendants, probably used for nose, rings, and ear-rings. These are not very common. M, to the right, is the series beginning with two forms of ridged unperforated gorgets which are coffin-shaped, and ending in the ridged gorget, opposite which (to the right) are drawn two arrows. On the right of the plate, in row N, is the ridged gorget terminating in the boat-shaped object; and below, the ridged form ending in two objects having elevated, horn-like protuberances in the centre. Row O, to the left, is the ordinary oval, not flat but thick and round, which may be slightly grooved at one end. This series progresses through forms with wide shoulders and narrow necks and long, pointed bodies. Of the purpose of these we possess no knowledge. Numbers of them are found in the United States; but none of the specimens shown at the right in row O (left side of sheet) have to my knowledge been found in mounds or graves. [Illustration: FIG. 305. (S. 1–5.) A good series of the flat, rectangular gorgets (also a few ovate ones) of all kinds. The three central objects and the lower central one do not belong in this classification. Students should examine all these twenty-seven objects carefully. Materials: slate, granite, sandstone, diorite. Collection of J. A. Rayner, Piqua, Ohio. ] The materials out of which these two hundred and twenty-one specimens are made are various shales, granite, sandstone, banded slate, mica schist, and porphyry. The arranging of all these types is not arbitrary. Another observer might group them in a different manner. I do not maintain that they should be grouped this way. But we have so many of them in our American museums that an attempt at grouping and classifying them should be made. About twelve years ago, just before Mr. Peabody endowed the Department of Archæology at Phillips Academy, I began the study of the problematical or unknown forms. I found that these objects were mentioned more or less briefly in nearly a hundred reports, books, and scientific papers. In the “Handbook of American Indians,” they are discussed under various heads and small illustrations are presented. [Illustration: