Rugose coral assemplages may be used to characterize Belgian Viséan strata but there are some dmerences between contemporary coral assemblages from the Namur-Dinant basin and from the Visé area (Campine-Brabant basin). The Namur-Dinant basin was a relatively closed environment usually separated from the Visé area by some kind of barrier. Corals could have migrated into it from Ireland or are endemic. In contrast, the Visé area was an open environment with corals showing affinities with those of the British Central Province, the USSR and Africa.