"The most unusual feature of Chicanel culture, however, is the high elaboration of architecture, above all in the latter part of the Late Preclassic, from 100 B.C. to A.D. 250. It must be remembered that the Petén-Yucatán shelf is blessed with an inexhaustible supply of easily cut limestone, and with abundant flint for tools with which to work it. Moreover, the Maya of the lowlands had discovered as far back as Mamón times that if limestone fragments were burnt, and the resulting powder mixed with water, a white plaster of great durability was obtained. And finally, they quickly realized the structural value of a concrete-like fill made from limestone rubble and marl.
With these resources at hand, the Maya temple architect was able to create some elaborate constructions at a very early date. At the great Petén sites of Uaxactún, Tikal, and El Mirador, deep excavations have shown that major pyramids, platforms, and courts were already taking shape by late Chicanel times. There is general agreement, for instance, that the E-VII-sub pyramid at Uaxactún was built late in the Chicanel phase; beautifully preserved by the overlay of later structures, this truncated temple platform is faced by brilliantly white plaster [which unfortunately has become moss-covered and blackened since its uncovering] and rises in several tiers each having the apron moldings which are so distinctive a feature of Maya architecture in the lowlands. On all four sides are centrally placed, inset stairways flanked by great monster masks which apparently represent the Jaguar God of the Underworld (the night sun), as well as sky-serpents. Postholes sunk into the floor show that the superstructure was a building of pole and thatch."
Michael D. Coe, The Maya, p. 61-2