:Permian rugose corals underwent evolutionary episodes of assemblage changeover, biogeographical separation and extinction, which are closely related to geological events during this time. Two coral realms were recognized, the Tethyan Realm and the Cordilleran–Arctic–Uralian Realm. These are characterized by the families Kepingophyllidae and Waagenophyllidae during the Cisuralian, Waagenophyllidae in the Guadalupian and the subfamily Waagenophyllinae in the Lopingian, and the families Durhaminidae and Kleopatrinidae during the Cisuralian and major disappearance of colonial and dissepimented solitary rugose corals from the Guadalupian to the Lopingian, respectively. The development of these coral realms is controlled by the geographical barrier resulting from the Pangaea formation. According to the changes in the composition and diversity of the Permian rugose corals, a changeover event might have occurred at the end-Sakmarian and is characterized by the mixed Pennsylvanian and Permian faunas to typical Permian faunas, probably related to a global regression. In addition, three extinction events are present at the end-Kungurian, the end-Guadalupian and the end-Permian, which are respectively triggered by the northward movement of Pangaea, the Emeishan volcanic eruptions and subsequent global regression, and the global climate warming induced by the Siberian Traps eruption.

This chapter presents a collection of first-generation Swiss geologists, who, around 1900, went abroad in order to work for oil organizations, both public and private. With the rise of oil exploration after 1900, the demand for experienced oil geologists grew rapidly. Oil companies started hiring trained geologists from different parts of the world, which led to an increasing number of Swiss geologists finding employment abroad. One of the first to start his career abroad was Carl Schmidt (1862–1923) from Basel, highly esteemed and later renowned for his achievements as a teacher of younger oil geologists. Another was Josef Erb (1874–1934), who accomplished an unparalleled career at Royal Dutch Shell. Other examples include Hans Hirschi (1876–1964), who worked for the Union des Pétroles d’Oklahoma for a few years, and Arnold Heim (1882–1965), working nearly 50 years for major oil companies. Many more followed over the decades to come, so that virtual successions took place between them: specific territories and specific companies were ‘handed down’ between geologists of the same nationality. Where once the Swiss were employed, others took over; the pioneers acted as door-openers for future generations.