During the period 1993-1999 the quaternary deposits have been mapped on the sheets ( 1 :50.000) Bruges, Lokeren, Tieltand Ghent (NW Belgium) using mainly barehole descriptions from several archives. The paper describes the fundamental mapping unit, the interpretation procedures and the elaboration of the legend and it presents an informal regional lithostratigraphical column (Tab. I). The lithostratigraphical maps show the vertical succe sion of the different lithotypes. A lithotype is a geological unit characterised by its specific lithology, its sedimentgenesis and its climatic-stratigraphical position. Each lithotype is represented by a letter symbol (Fig.4) and each specific succession (lithoprofile type) by a code composed of the succession of the lithotype symbols (Fig.3). The lithoprofile map has a double legend. The analytica! version provides the lithoprofile type codes (Fig.5). lts legend is simple and easy to memorise. It allows an easy digitalisation. Thickness of the units is shown on additional thematic maps. The synthetic version shows a speci fic colorfor each of the lithoprofi Ie types (Fig. 7). Reading those maps demands a contim1ous return to the legend. That mode of representation however allows to oversee at once the spatial distribution of any lithoprofile type. It also allows to underline certain priorities or classification modes of lithoprofile types. Both versions ofthe lithoprofile type map are easily transforn1ed into a lithostratigraphical profiletype map by adaptation of the legend. That application however demands the definition of forma! quaternarylithostratigraphical units. Maps and comments may be consulred on the website http://dov.vlaanderen.be of the Ministry of the Flemish Community.