NO. 1 CULTURAL DEVELOPMENT IN LATIN AMERICA 21 
termixed with the Plateau tradition, as at Chalcatzingo, Gualupita, 
Tlapacoya, and Tlatilco. Elsewhere, both traditions followed an in- 
dependent evolution, as can be observed at such sites as Zacatenco, 
El Arbolillo, Copilco, La Venta, Tres Zapotes, Trapiche, Vie j on, 
Panuco, and El Openo (fig. 3) . 
Urban Formative Period (800 to 200 B.C.) — The transition from 
Village Formative to Urban Formative reflects an important step for- 
ward in the economy, making possible the support of temples and a 
priesthood. The existence of these requires a major technological ad- 
vance, an increase in population size and density, a more marked di- 
vision of labor, stronger social organization, and the production of a 
food surplus. 
During this period, some towns were transformed into ceremonial 
centers, which served as a focus for the population of the surround- 
ing area. The increased population implies a more intensive form of 
agriculture. Larger areas of forest were cleared for fields, and in 
some places terraces were constructed to counteract erosion of the 
slopes. The developing priestly class acquired political control 
through its religious, economic, and administrative functions. The 
pantheon included a god of fire (Huehueteotl) and an early form of 
the god Tlaloc. 
Among architectural achievements, stone-faced platforms are com- 
mon, as well as stepped platforms of rectangular or circular plan, 
earth mounds, and altars. Pyramidal structures exist but are rare and 
simple in construction. Building materials included stone, river cob- 
bles, mud, earth fill, and, toward the end of the period, stucco. 
In some places the calendar was beginning to develop; in others, 
the burial of important persons began to take place in tombs of stone. 
Other variations include severing of heads as trophies, placing of the 
body on a couch of bark, and radial burials. Glyphic writing, polish- 
ers for floors and walls, and other new elements appeared, and trade 
relations between groups were intensified. 
Among the principal crafts are pottery making, weaving, basketry, 
and stone working. Pottery decoration is mainly polychrome (red, 
black, white, cream, buff, orange), but other common techniques are 
negative painting, fresco, and white-on-red. New ceramic elements 
include mammiform supports, tetrapod supports, spout with bridge 
handle, basal flange, tall annular base, ring base, zoned painting 
(bounded by incised lines), and applique adornos on the vessel body. 
Figurines are made by applique or are well polished and painted. 
Smiling-faced, solid, handmade figurines, and hollow polychrome 
ones also occur. Other diagnostic traits of this period are obsidian 
