The Silurian of the Brabant Massif crops out in the Sennette valley, near Ronquières. From these outcrops, the Mont Godart Formation is defined and the formerly poorly defined Ronquières Formation is redescribed in detail. Seven informal units, four of them divided into subunits, are distinguished in the Ronquières Formation. Based on Chitinozoa and graptolites, the age of the Mont Godart Formation is estimated possibly latest Homerian (Wenlock) or earliest Gorstian (Ludlow) and that of the Ronquières Formation as Gorstian (Ludlow). Four sedimentological facies occur: mud-grade turbidites predominate and are interbedded in anoxic laminated hemipelagites. Oxic bioturbated hemipelagites and metabentonites occur rarely. The palaeoenvironment of the sedimentary basin is interpreted as a turbiditic fan system directed to the east in a E-W trending trough with apparently northward directed currents. A major megacycle spans both formations. Relatively high energy sediments are present in the bottom of the Mont Godart Formation and in the top of the Ronquières Formation. Less energetic sediments, indicating a deeper sea environment, are found in between. A similar cycle of deepening and shallowing has also been observed in the late Wenlock and early Ludlow of the Welsh Borderland and of Gotland on the Baltic platform.