Recent archaeological investigations along the lower Negro and upper Xingu
Rivers in the Brazilian Amazon provide important new evidence bearing on lo
ng-standing debates about the size and permanence of Amerindian settlements
in the region. Preliminary regional surveys and more in-depth study of sel
ected large (30-50 ha) sites, particularly analyses of the associations bet
ween structural features, anthropologically altered soils, and artifact dis
tributions, lead us to conclude that large, permanent settlements, likely a
ssociated with fairly dense regional populations, existed prehistorically i
n both areas. These findings cast doubt on the view that environmental limi
tations prevented sedentism and demographic growth among Amerindian populat
ions throughout much or all of the region. Specifically, we conclude that f
ully sedentary and relatively large populations emerged in a variety of Ama
zonian settings prehistorically, not necessarily correlated with the distri
bution of one or another narrowly defined ecological variable (e.g., high f
ertility soils). Thus, a critical evaluation of core concepts in Amazonian
anthropology, such as the varzea/terra firme dichotomy or tropical forest c
ulture, is advised.