The lower Laclo River valley, which empties into the sea near Manatuto, is one such area.
The survey area, about 40 [km.sup.2], covers the lower floodplain of the Laclo River and the Lamessana lagoon to the east (Figure 5).
The eight fortified hilltop sites all have restricted access and far-reaching views overlooking the Laclo River mouth and lowland plains.
Many of these earlier sites also lie further from the Laclo river basin (Figure 5).
The record of fortifications on the landscapes of Tutuala, Ira Ara and on the lower Laclo River in Manatuto meets these conditions, a) All three areas were largely dependant on agriculture for subsistence, b) In all three areas, fortifications appear on the landscape primarily between 1150-1550 AD.