Carlos Ribeiro, one of the directors of the Geological Commission of Portugal, voyaged in 1858 to many countries of Europe to acquire publications, equipment and comparator collections. In Paris he met Paul Deshayes, a well-known conchologist, who gave him access to his personal collections of Tertiary deposits from France and helped him to classify Portuguese fossils. The outcome of the joint work can be seen in the Ribeiro List, which is preserved in the historic archives of the National Energy and Geology Laboratory (Alfragide, Portugal). These classifications served as a basis for a monograph published by Pereira da Costa, Ribeiro's colleague on the Geological Commission, and the definition of the stratigraphy of Portugal's Tertiary deposits.