NO. 1 CULTURAL DEVELOPMENT IN LATIN AMERICA 19 
Incipient Agricultural Period (6000 to 2000 B.C.) — At the be- 
ginning of the Altithermal Period, many of the grasslands began to dry 
up, causing the dispersion and extinction of the large mammals and 
forcing man to adapt himself to new ecological conditions. He may 
have done this partly by migrating to areas where the environment 
was more favorable, such as the Sierra de Tamaulipas, the Valley of 
Tehuacan, the coast of the Gulf of Mexico, Chiapas, and other re- 
gions. In these areas, as the climatic conditions became once more 
stabilized in the direction of increased humidity, some of the groups 
gradually converted from collectors of wild foods to incipient cul- 
tivators. Specialized techniques were developed for the acquisition 
and preparation of food, and are reflected in a new tool inventory in- 
cluding mortars, metates, manos, hammerstones, bark beaters, and 
awls. 
The survival of some of the techniques of the nomadic hunters is 
attested by finds of Lerma points in the Cueva de Coxcatlan, Puebla, 
and in the Sierra de Tamaulipas (MacNeish, 1961, p. 23), where 
they are associated with artifacts of the Incipient Agricultural tradi- 
tion. Other finds, such as those of Santa Marta in Chiapas, Chalco, and 
Chicolaopan in the Valley of Mexico, and Frightful Cave in Coa- 
huila, attest to the presence of similar groups and provide the first 
evidence of the cultivation of maize (at least by 3500 B.C.) and 
squash, the manufacture of baskets and cloth, burial practices, and 
possibly of pottery making, since crude sherds have been found in 
Coxcatlan below levels with pottery of Formative types. 
FORMATIVE HORIZON (2000-200 B.C.) 
Village or Rural Formative Period (2000 to 800 B.C.) — By the end 
of the preceding period, groups in several areas had laid the founda- 
tion for what would become the Mesoamerican cultural complex. By 
at least 1700 b.c. farming communities had developed. These are 
aligned in two important cultural traditions, that of the Central 
Plateau and that of the Gulf coast. These societies depended upon 
maize agriculture for their principal subsistence, but also drew upon 
the resources of wild plant and animal foods when they were available. 
Among their common and diagnostic characteristics were the manu- 
facture of highly developed pottery, special burial practices, limited 
trade relations, and a simple form of social organization. 
Settlements are along rivers, lakes, or arroyos, or on the coast, 
agriculture being dependent on rainfall and on natural flooding of the 
land. Maize, squash, beans, and possibly cotton and manioc were cul- 
tivated. Later, slash-and-burn technique made possible the utilization 
