Two rather different elements combine to explain the origin of this volume: one scientific and one personal. The broader of the two is the scientific basis-the time for such a volume had arrived. Geology had made remarkable progress toward an understanding of the phys ical history of the Caribbean Basin for the last 100 million years or so. On the biological side, many new discoveries had elucidated the distributional history of terrestrial orga nisms in and between the two Americas. Geological and biological data had been combined to yield the timing of important events with unprecedented resolution. Clearly, when each of two broad disciplines is making notable advances and when each provides new insights for the other, the rewards of cross-disciplinary contacts increase exponentially. The present volume represents an attempt to bring together a group of geologists, paleontologists and biologists capable of exploiting this opportunity through presentation of an interdisciplinary synthesis of evidence and hypothesis concerning interamerican connections during the Cretaceous and Cenozoic. Advances in plate tectonics form the basis for a modern synthesis and, in the broadest terms, dictate the framework within which the past and present distributions of organisms must be interpreted. Any scientific dis cipline must seek tests of its conclusions from data outside of its own confines."

The Second International Symposium on Observation of the Continental Crust Through Drilling (supported by the Alfred Wegener Foundation, the Federal Ministry of Research and Technology, the German Research Society and the Inter-Union Commission on the Lithosphere) took place in Seeheim (Odenwald) and included a discussion on the Continental Deep Drilling Programme of the Federal Republic of Germany. This sym- posium was regarded as the continuation of a course agreed upon in Tarrytown in 1984. Here, the scientific contents and technical con- cepts of the technically complex and expensive experiments of conti- nental drillings were carefully coordinated before the national commit- tees carne to practical decisions. In Seeheim, rather than in Tarrytown, the methods of technical realization were in the foreground, as the results of scientific projects, e. g. , the NAGRA or the Salton Sea Scien* tific Drilling Project, were evaluated, supplementing industrial ultra- deep drilling experience. The presentation and discussion of the Con- tinental Deep Drilling Project of the Federal Republic of Germany was also granted ample scope with nine lectures and sixty posters. The con- tents of the KTB presentation have been summed up in two contributions and included in this volume. The conference centered on three major subjects: The National- Prograrrunes and Aspects of Geoscience: H. Vidal, FRG; H. Riesen- huber, FRG; E. Seibold, FRG; K. Fuchs, FRG; Cl. Megnien, F; R. S. An- drews, USA; F. G. Stehli, USA; E. A. Kozlovsky, USSR; E. V.