Several factors are responsible for the distribution of the malacological fauna on the beaches of our coast. A detailed analysis of this fauna (4309 individuals from 93 species), sampled in the mean tide level on the beach over a distance of 6 km (starting from the harbour of Ostend towards Klemskerke), shows the presence of marine, brackish water, freshwater shells together with landsnails. After grouping the different species with reference to their ecological affinity, distribution histograms were made and a statistical analysis was executed. Due to these distribution tests the unexpected presence of freshwater and brackish water species has been corresponded with the existence in the past of outflow channels and a wadden landscape. Such type of analysis seems to give very good complementary research tools for the study of the recent geology of the coast and for local archaeological investigations.