1. INTRODUCTION
The Paleogene of Belgium is divided into 23 formations. Eighteen formations are placed into 8 groups: the Chalk Group (Houthem Fm), the Haine Group (Ciply Fm, Mons Fm and Hainin Fm), the Landen Group (Hannut Fm, Tienen Fm), the Ieper Group (Kortrijk Fm, Tielt Fm and Gentbrugge Fm), the Zenne Group (Aalter Fm, Brussel Fm and Lede Fm), the Tongeren Group (Zelzate Fm, Sint-Huibrechts-Hern Fm and Borgloon Fm) and the Rupel Group (Bilzen Fm, Boom Fm and Eigenbilzen Fm). The Opglabbeek Fm, Bertaimont Fm, Heers Fm, Maldegem Fm and Voort Fm are not placed into a group. The occurrences of the paleogene formations are illus-trated in Figs. 1, 2 and 3. A subdivsion of the formations into members or layers is given. However, this subdivision must not be considered as formal since some of the members are still under debate. Stratigraphic units with a rather local significance such as the Hyon Fm and the Onhaye Fm are not yet incorporated in this overview. The latter formation is considered as a tertiary relict found in sinkholes of the Sambre and Meuse region.
