Outlines of two additional examples of these objects are given in Figs. 12 and 13. The tablets are round, thick, and slightly concave above and are margined with rows of sculptured heads. The supporting column in the first is a plain shaft and the base is narrow and somewhat concave underneath. In the second the column is hollowed out and perforated. [Illustration: Fig. 13. Stool with perforated base, carved from gray basaltic rock--⅓.] As bearing upon the possible use of these specimens it should be noticed that similar stool-like objects are made of clay, the softness and fragility of which would render them unsuitable for use as mealing plates or mortars, and it would also appear that they are rather fragile for use as stools. I would suggest that they may have served as supports for articles such as vases or idols employed in religious rites, or possibly as altars for offerings. _Celts._--The class of implements usually denominated celts is represented by several hundred specimens, nearly all of which are in a perfect state of preservation. They are thoroughly well made and beautifully finished, and leave the impression upon the mind that they must represent the very highest plane of Stone Age art. Although varying widely in form and finish there is great homogeneity of characters, the marked family resemblance suggesting a single people and a single period or stage of culture. They are found in the cists along with other relics and are very generally distributed, a limited number, rarely more than three, being found in a single grave. They may be classified by shape into a number of groups, each of which, however, will be found to grade more or less completely into the others. They display all degrees of finish from the freshly flaked to the evenly picked and wholly polished surface. The edges or points of nearly all show the contour and polish that come from long though careful use. All are made of compact, dark, volcanic tufa that resembles very closely a fine grained slate. The following illustrations include all the more important types of form. There are but few specimens of very large size. That shown in Fig. 14 is 8¼ inches long, 4 inches wide, and seven-eighths of an inch thick. The blade is broad at the edge, rounded in outline, and well polished. The upper end terminates in a rather sharp point that shows the rough flaked surface of the original blocking out. The middle portion exhibits an evenly picked surface. The rock is a dark slaty looking tufa, the surface of which displays ring or rosette-like markings, reminding one of the polished surface of a section of fossil coral. These markings probably come from the decomposition of the mineral constituents of the rock. [Illustration: Fig. 14. Large partially polished celt of mottled volcanic tufa--½.]