A concentration of pits in a very small area was excavated at Outeiro Alto 2. The concentration was generically circular (Figure 1).
The pits were all almost empty of archaeological material. In the periphery there were three Late Neolithic hypogea and a grave pit (Figure 2).
To try to understand the concentration of pits in this small area, with no overlaps and surrounded by tombs, a study of the morphology and volumes of the pits was done. It was possible to cluster the pits in three groups of sizes and deepness (Figure 3).
When those clusters were plotted in the plan, a pattern emerged (Figure 4): the deepest pits formed a circle with a square in the centre and two pits towards north; then surrounded by the smallest pits; and the intermediate pits scattered in the SW area.
The distribution, the size of the central pits and the absence of archaeological material inside them (just two or three small shards of pottery) clearly suggest a circular wooden structure of henge type surrounded by the tombs.
This context is published here: Valera & Filipe,2012.