A field workshop of the International Geoscience Programme (IGCP) Project 499 entifled 'Devonian Land-- Sea Interaction: Evolution of Ecosystems and Climate' (DEVEC)was held between 14 and 22 May 2007 in San Juan, Argentina. The Devonian of the San Juan and Mendoza Precordillera and the San Rafeal Block are of special interest for the project due to the palaeogeographic and biostratigraphic importance in the Devonian Malvinokaffric Realm, but also in the tecto-sedimentary evolution of the Precordillera terrane.