Structures 2C7 and 2C8, Ruppert 1952:Figs. 12, 13
related sculptural forms presents challenges because it is unknown when the first serpent ramps were carved at Chichén Itzá. In the sequence on the main plaza, serpent ramps first appear on the Temple of the Warriors. It is unknown whether the Chac Mool Temple had them, and the north ramps of the Castillo, with the serpent heads below, are plain. Serpent ramps at the Ball Court, when present, are carved in half round, and are therefore not clearly comparable, and the undulating serpents on the ramps of the Caracol may have been later additions. Thus, there are no positively early examples of the undulating serpent on a stairway ramp, nor is it common to omit a serpent head carved in full round from ramp or column. All things considered, the serpent column from structure 2C3 is probably a late form, carved for the same symbolic effect as the carvings in full round but requiring much less effort on the part of the sculptors. What evidence there is suggests that the Northwest Group is late in the architectural sequence at the site.
Conclusions Study of the outlying groups reveals that the architects of Chichén Itzá usually, but not invariably, followed certain conventions of group organization and development. The closest parallels in courtyard organization are observed between the north court of the Initial Series Group and the northwest court of the Southwest Group, where five buildings of similar type in each group occupy similar locations on the court in relation to each other. A similar, although not quite so close, arrangement is seen in the Group of the Bird Cornice, and three of the much ruined structures in quadrant 3B seem to have this nucleus of courtyard development. The general pattern is this: a central two-chambered structure or “temple” stands on the east side of the court, facing west or northwest. Adjacent to the south and slightly east is a gallery patio structure. A small colonnade might enclose the north end of the court, and this colonnade might 128