buildings consists of a series of chambers, like the buildings at Quiengola described above (Fig. 32, a; p. 175), though on a smaller scale; another consists of a shrine standing free within an exterior building. Other similarities to Oaxaca remains include the presence of pillars to support a roof, found in a building in the neighbourhood, and again on a foundation-mound at San Isidro, immediately south of Misantla; and also numbers of heads, but in this case of clay, which appear to have been inset in the walls. At Texolo are mounds some of which are of earth alone, and these are occasionally arranged in a double row to enclose a court. Stone facing however is not unknown in this district. Of architectural remains as a whole it may be said that the Aztec buildings show a tendency to simplicity and exhibit on the whole fewer traces of arrangement on a large and comprehensive plan, such as may be observed at Teotihuacan. Teotihuacan itself, as far as actual buildings are concerned, has many points in common with Tulan, and in its general arrangement shows a considerable similarity to Monte Alban. The last-named site is obviously closely connected with other remains in Oaxaca; and Xochicalco, from its decoration, has similar affinities, affinities which extend to the pre-Aztec remains of the valley. Mitla stands practically by itself as far as artistic ornamentation is concerned, though the arrangement of the buildings is quite Oaxacan in character. The Totonac ruins display a certain affinity with the ruins at Quiengola, though this affinity cannot be said to be direct. The true relation between the two will be more apparent after the Maya remains have been considered. It is unsafe to draw any conclusion from structural points alone, since so much depended upon the presence in the neighbourhood of suitable materials; it was, for instance, the presence of trachyte in the Mitla region which enabled its builders to make use of large masses of stone, and pro-
