The 3,000-year-old finds consist of remnants of a square platform and a long platform separated by a plaza, say archaeologist Takeshi Inomata of the University of Arizona in Tucson and his colleagues. Critically, the two structures run from east to west. Renovations to the square platform transformed it into a 6- to 8-meter-high pyramid by around 2,700 years ago. A new version of the long platform was built behind the original at that time. That layout, joining a square or pyramid with a platform in an east-west alignment, formed the centerpiece of ritual areas in many later Maya cities. Ceremonial structures at Ceibal and nearby sites got the cultural ball rolling, the researchers suggest, in a Maya society that eventually featured writing, a complex calendar and massive temples.So at the bottom this dig they did not find people who were recognizably Mayan but not yet possessed of Mayan-style ceremonial architecture. Instead, they found people who were not Mayan in most ways but already had the basic temple-courtyard complex that would be the ceremonial center of every Maya city to come. Their conclusion was that the ceremonial complex came first, and that Mayan culture grew from the fusion of previously disparate peoples through the adoption of the religion and its rites.
A comparable argument, I suppose, would be to say that the civilization of western Europe formed from the disparate cultures of the early Middle Ages largely through the spread of the Latin church.