The potter, in preparing the vessel for the decorator, ordinarily finished it with a slip or wash of fine clay, which varied in hue from a gray white to a pale orange. A slip of bright red tint was also extensively used. The more delicate hues formed an excellent ground upon which to work. The slip covered surface was generally polished, often to a high degree, with the usual polishing implements, the marks of which can be seen upon the less carefully finished surfaces. By observers unacquainted with aboriginal methods this polish is liable to be taken for a glaze, and it has been pronounced a vitreous glaze by a few writers. It is more noticeable upon specimens that have been handled a great deal, as is the case with whistles, needlecases, and the like. The colors utilized in decoration, so far as they have been preserved, are the ground tints, described above, and the delineating colors, the latter consisting of black, white, red in various hues, and a dull purple. An additional color (or perhaps a solution without particular color) extensively employed in the designs has totally disappeared. The nature of the various colors has not been determined, but it is probable that some were of mineral and others of vegetal origin. Red was often employed as a ground color, as stated above, and sometimes covered the whole surface, but more frequently occupied zones or panels. In such use it was applied and polished down with the slip. Red was also extensively used in the delineation of decorative figures in several of the groups of ware, and is in all cases a permanent color. The hues vary decidedly with the groups of products, suggesting differences in people or in environment. White may have been freely used, but it is preserved in a few cases only, in which it was used in the production of simple decorative patterns, and appears to have been a somewhat thick or pasty color. Black was extensively used and was of two distinct kinds: a thick permanent pigment, employed in the delineation of designs, and a thin color, not so permanent and employed exclusively as a ground upon which to execute designs in other mediums. The latter may possibly be of vegetal derivation. Its use was confined to a single variety of ware, the lost color group. The former was employed in all the other groups, with one exception, the red line group. The light purple tint is but sparingly used and only in the polychrome group. It is very effective in combination with the reds and blacks upon the orange ground of this ware. It is probably of a mineral nature.