“…However, negative stratigraphic units, which sum a significant amount of the material record, have largely been invisible until very recently, largely due to lack of knowledge of specific methodologies and of the scientific developments in other European regions (Hamerow, 2011). While this type of construction has been known in the Anglo-Saxon world from the 1930s (Leeds, 1936;Ralegh Radford, 1957), and in Germany and France from the 1960s (Chapelot and Fossier, 1980;Demolon, 1972;Donat, 1980), their existence in the Iberian Peninsula was only identified in the late 1990s (Vigil-Escalera, 1999), followed soon by the first typological studies on these constructions (Azkarate and Quirós Castillo, 2001;Vigil-Escalera, 2000).…”