Attention may be called to the fact that not only the adobes found at Cliff Palace but also the mortar used in the construction of the walls contain ashes and sometimes even small fragments of charcoal. Clay or adobe plastered on osiers woven between upright sticks, so common in the walls of cliff-dwellings in Canyon de Chelly and in the ruins in the Navaho Monument, while not unknown in the Mesa Verde, is an exceptional method of construction and was not observed at Cliff Palace. The survival[25] of this method of building a wall, if survival it be, may be seen in the deflector of kiva K. [Footnote 25: In at least one of the Oraibi kivas the plastering of the wall is laid on sticks that form a kind of lathing. Whether this is a survival of an older method of construction or is traceable to European influence has not been determined, but it is believed to be a survival of prehistoric wall construction.] PLASTERING The walls of a number of rooms were coated with a layer of plastering of sand or clay. This was found on the outside of some walls, where it is generally worn, but it is best preserved on the interior surfaces. Perhaps the most striking examples of plastering on exterior walls occurs on the Speaker-chief's House, where the smoothness of the finish is noteworthy. From impressions of hands and fingers on this plastering it is evident that it was laid on not with trowels but with the hands, and as the impressions of hands are small the plasterers were probably women or children. In several instances where the plastering is broken several successive layers are seen, often in different colors, sometimes separated by a thin black layer deposited by smoke. The color of the plastering varies considerably, sometimes showing red, often yellow or white, depending on the different colored sand or mud employed.[26] The plastering not only varies in color but also in thickness and in finish. In the most protected rooms of the cave practically all the superficial plastering still remains on both the interior and the exterior of the walls, but for the greater part it has been washed from the surfaces and out of the joints in the outer buildings. The mortar was evidently rubbed smooth with the hands, aided, perhaps, with flat stones. The exterior of one or two rooms shows several coats of plaster, and different parts of the same walls are of different colors. Indistinct figures are scratched on several walls, but the majority of these are too obscure to be traced or deciphered. The plastering on the exterior and the interior of the same wall is often of different color. [Footnote 26: The red color is derived from the red soil common everywhere on the mesa. Yellow was obtained from disintegrated rock, and white is a marl which is found at various places. The mortar used by the ancient masons became harder, almost cement, when made of marl mixed with adobe.] PAINTINGS AND ROCK MARKINGS