The enclosure is not entirely on top of the small hill; starting from the top, it develops along the southern slope facing the stream, with limited visibility over the surrounding landscape. Its prevailing section has two concentric ditches, with the larger axis in a northwest-southeast direction. The outer ditch is 180m x 140m, about 10-12 metres from the inner ditch, a similar distance to the double outer ditches found in other enclosures (like Perdigões, Salvada, and Folha do Ouro, the latter of which is on the southern route), suggesting a pattern. Ditch 1 has an entrance on the south-east side, which corresponds to a gap about 5/6 metres wide, in front of which there is a small semi-circular ditch, similar to the doors in the outer ditches of Perdigões and other enclosures. Ditch 2 has an entrance with a simple gap in the same area, although smaller and slightly to the left than the previous one, and another to the north. There seem to be three entrances to the inner enclosure: the most obvious is to the south; another appears to correspond to a ditch hiatus at the west end; the last to a ditch hiatus on the east lobe. The entrances do not have a patterned orientation, but it is interesting to note that the enclosure’s axis is orientated at 120º, i.e. at the winter solstice. Recent surveys attributed this enclosure to the Chalcolithic period, with bell-beaker ceramics (second half of the 3rd millennium BC) and some human bones collected inside a ditch, an unusual situation in these smaller enclosures.

The main specificity of the Montoito enclosure is the ellipsoidal plan of its double external ditch. It is unique within Alentejo and even Iberian ditched enclosures but has known parallels, for example, in Germany. The curved lines prevail in the architectural design of these sites; there are no right angles, and very open angles only appear in the outermost ditches of Moreiros 2 (Arronches). The curve reigns supreme in the tendency towards circular and concentric plans or in the winding layout of many of the ditches. But the said form, which also features curved lines but is geometrically similar to an ellipse, only exists in Montoito. This tendency towards circularity relates to Neolithic worldviews, notably in how the circular design (but also the oval or ellipsoidal) articulates with cyclical perceptions of time and the mythologies of eternal return that could have integrated these worldviews.

Archaeological surveys and geophysical prospecting using magnetometry.

Valera, A.C.; Becker, H. Costa, C. (2014), “Os recintos de fossos Pré-Históricos de Monte da Contenda (Arronches) e Montoito 2 (Redondo)”, Estudos Arqueológicos de Oeiras, 21, CMO, 195-216.