The record of Lower and Middle Devonian sedimentation in the SW border of the Iberian Massif is scarce. The scattered presence of uppermost Lower Devonian to Middle Devonian limestones in the SW margin of the Ossa-Morena Zone sheds light on the local and regional paleogeography and allows to clarify geodynamic models for the northern Gondwana realm during the Devonian. The several studied localities show the presence of isolated reef structures and spatially associated calciturbidites, interpreted as a result of the erosion of the reef buildings. Coeval volcanic rocks suggest reef development was supported by volcanic edifices, but in other instances basement highs may have supported the reef structures. Two global events, the basal Choteč and the Kačák, are recorded in these limestones, providing a better understanding of the paleogeographical extent of these events and their lithological, stratigraphical and paleoecological expression
