Ordovician Basins of Argentina / Ricardo A. Astini -- Biostratigraphy / Edsel D. Brussa, Blanca A. Toro, and Juan L. Benedetto -- Paleobiogeography / Juan L. Benedetto -- Paleoecology and biotic events / Teresa M. Sanchez et al. -- Precordilleran reefs / Fernando L. Canas and Marcelo G. Carrera -- Sponges and bryozoans / Marcelo G. Carrera -- Brachiopods / Juan L. Benedetto -- Bivalves and rostroconchs / Teresa M. Sanchez -- Trilobites / Beatriz G. Waisfeld and N. Emilio Vaccari -- Ostracods / Maria J. Salas -- Graptolites / Blanca A. Toro and Edsel D. Brussa -- Trace fossils / M. Gabriela Mangano and Luis A. Buatois.