NO. 1 CULTURAL DEVELOPMENT IN LATIN AMERICA 107 
that in the future it will be possible to define an Initial Monochrome 
Pottery Horizon represented by Cienaga I, Tafi, Pichalo, Candelaria 
I, Molle I, and Molle II. 
Intermediate or Middle Ceramic Period (a.d. 700 to 1000). Tia- 
huanacoid influence is evident particularly in the Puna de Atacama. 
In northwestern Argentina, the period is marked by the florescence 
and decline of the Aguada Culture, Haulfin (?) and San Jose. An- 
other complex of this period is Pozuelos. 
Late Ceramic Period (a.d. 1000 to 1450). Well-integrated local 
complexes emerge. Ceramically, the area is united by the Late Bicolor 
Horizon. Representative complexes include : Belen, Santamaria, San- 
gasta, Hornillos, Tilcara Black-on-Red, Coquimbo Clasica, Puneno, 
Arica I, and Atacamenan urban centers. 
Empire or Inca Period (a.d. 1450 to 1550) . 
Early Ceramic Period. — The dates now in our possession indicate 
rather clearly that pottery-making cultures arrived in northwestern 
Argentina between 500 B.C. and the beginning of the Christian era. At 
this time, there were already two well-differentiated traditions. These 
first pottery complexes were superimposed on preceramic complexes 
of the Intihuasi II and III type. Although we cannot be certain 
whether or not these latter groups were incipient agriculturalists, we 
do know that they had hunting and gathering economies with strong 
emphasis on the latter practice (as indicated by the abundance of flat 
milling stones), which would have facilitated the acceptance of agri- 
culture. 
It is difficult to trace the derivation of the two early pottery tradi- 
tions, Tafi and Candelaria I. The closest affiliations of Tafi appear to 
be with the Mound Culture or Chullpa-Pampa-like complexes of 
south-central Bolivia. Our information on these is exceedingly sparse, 
but the pottery types seem closely related. The second tradition, Can- 
delaria I, resembles more the pottery later developed among the Pa- 
rana River cultures. Its origin should probably be sought via the large 
rivers or along the eastern slope of the Andes at the edge of the 
Tropical Forest. 
The Cienaga gray incised pottery tradition, which appears slightly 
later, is analogous to that found in the region of the Selvas Occi- 
dentals (Valley of the San Francisco), suggesting that its origin 
may lie in that direction, or in southern Bolivia. It is unreported so 
far in the Puna and in northern Chile. Some traces exist in the region 
of the Valles Transversales, which have been classified as Molle, but 
these appear from their quantity and type to be importations or influ- 
