That seems to be a significant difference between walled and ditched enclosures in Portugal.
Tor in the top of a hill used to built Castro de Santiago during Chalcolithic
Naturally, as argued before (for instance here), no building is performed in an insignificant space. Everything built is in dialogue with a local landscape, with its meanings, visibilities, resources, particularities. And all of those previous conditions are, in one way or another, incorporated in the building.
But when we compare walled and ditched enclosures we can observe that the former tend to present a great variety of forms of adaptation and incorporation of previous elements of the landscape, while the ditched enclosures mainly reflect a dialogue with topography, geology and visibility conditions.
Rocks, tors or cliffs, are usually incorporated as part of the structures that enclose. Although in other parts of Europe we can see that also in ditched enclosures (like the French “enceinte à éperon”), so far those solutions were not identified in Portuguese ditched enclosures.
Large wall from rock to rock that defines the inner enclosure at Castro de Santiago.
In terms of the architectonic features, walled enclosures seem to use the available natural conditions in a different way. Perhaps one of the reasons is that the design, the layout, was less significant than the ones presented by ditched enclosures and answered to different goals.
Plan of the several walled structures that, together with the previous rocks, define Castro de Santiago enclosure.