This field guide will provide a good insight into the Lower Palaeozoic geology of the Dyle (first day) and Senne (second day) basin areas, which are among the most important and extensive outcropping zones of the Brabant Massif. Fifteen selected outcrops are visited. They cover all the stratigraphic range observed in the Brabant Massif from the Lower Cambrian (Blanmont Formation) to the upper Silurian (Ronquières Formation) and also the Brabantian unconformity. An up-to-date geological introduction syntheizes the most recent publications and the results of the recent 1/25,000 scale mapping of the Brabant. In each stop, a detailed description is provided of the location, stratigraphy, lithology and structural architecture, followed by interpretations. The observations and their implications are placed in the broader context of the Cambrian to Devonian odyssey of the Brabant Massif within the wandering history of the Avalonia microplate.