Morphologically, the Hautes Fagnes area (NE Belgium) is at present a regional high, rising some 100-150 m above the Ardennes plateau, which is slightly inclined to the NW (1°). Recently, a number of residual Late Cretaceous deposits in this area have been sampled in an attempt to reconstruct the gradual Campanian-Maastrichtian transgression onto the area, which acted as a monadnock during this period. Each succession starts with a basal conglomerate, which becomes progressively younger towards the summit of the Hautes Fagnes, indicating the step by step inundation of the area. The deposits have been analysed for bioclast assemblages, fish remains and phosphatised macrofauna, as well as for various microfossil groups, such as forams, ostracodes and sponge spicules. These allow a brief discussion of the paleoenvironment and age of these completely decalcified strata.