ing in accordance with a definite plan prepared beforehand. In Chichen Itza grotesque masks are found in some of the buildings, composed of details which do not fit into the scheme, a fact which proves that the Maya mason was not above utilizing material gleaned from the ruins of former buildings, besides affording evidence that such structures are of later date. It has already been mentioned that circular columns are peculiar to Yucatan, and it may be added that a variety of ornament derived from them was also applied to the outer surface of buildings, in the form of series of pilasters, such as are found at Sayil, and Labna and elsewhere (Pl. XXV, 1; p. 332).
Mortar, obtained by burning the local limestone, besides being used in great quantities for the hearting of buildings, was also employed for flooring, and, as stucco, for making up defects in wall-surfaces and designs. Besides this it was extensively used for moulded decoration at certain sites, notably Palenque. Here the limestone is of a very hard variety, and difficult to work with such tools as the Maya possessed; as a result, the art of modelling in relief attained a great development, and some of the finest works of Central American art are those produced by the stucco-workers of Palenque. Where the relief is low, the stucco has been employed alone, but where bold effects were desired, as on the roof-combs, a regular skeleton of the design has first been prepared, of limestone blocks, over which the stucco has been applied and moulded to the requisite form.
Colour formed an important aid to Maya ornament, and was frequently applied to stone carvings. It seems to us rather barbarous to cover fine stone reliefs with a coat of coloured stucco, but the Maya artist had no scruples on this score, and reliefs have been found at Palenque to which several layers of the above have been applied at different times. Many of the stelæ, especi-
