Abstract George Gaylord Simpson (1902-1984) dominated American paleontology for some five decades spanning the middle of the twentieth century. This dominance was both quantitative and qualitative, for Simpson not only published hundreds of articles, monographs, and books (his bibliography includes more than 750 entries), but his work had major impact on contemporary views of the origin, classification, and evolution of mammals; historical biogeography; principles of taxonomy and systematics; biostatistical methods; and most significantly, the formulation of the modern evolutionary synthesis. The Capitol Heights neighborhood of Denver where Simpson spent his youth includes two of the houses where he lived; the home of his childhood playmate and future wife Anne Roe; the church where he pumped the organ and whose teachings he eventually disavowed; the elementary school where he excelled as a student and suffered for it; the firehouse where the fire horse died; and the corner where he sold lemonade for spending money.

Abstract In the two decades preceding the establishment of plate tectonics theory, G. G. Simpson wrote a series of papers that refuted the paleobiogeographic evidence purportedly requiring direct continental connections. So cogent was his rebuttal that drift proponents thereafter downplayed the past distribution of fossils. Simpson presented several different arguments. He restricted his discussion to Cenozoic mammals with whose evolutionary history he was most familiar; he challenged the accuracy of the proponents舗 data; he criticized their methodology, both with respect to its undue appeal to authority and its lack of parsimony; he used his own “coefficient of faunal similarity” to show that present-day mammal distributions on dispersed continents are comparable to those for Tertiary continents; and perhaps most effective was his statistical argument that trans-oceanic dispersal of organisms, while highly improbable for a single event, is practically certain given the many opportunities for such events over geologic time spans. Simpson舗s objections arose from his own independently developed theory of historical biogeography which, by relying on mobile organisms dispersing across stable continents, was fully adequate to explain the paleobiogeographic data. Simpson thus regarded both drift theory and trans-oceanic land-bridges neither sufficient nor necessary to account for those data.

Abstract This collection of papers examines various aspects of reef form and development. Despite their variety of topic and treatment, they have two unifying elements: a fresh look at old themes and historical evolution. Although much has already been written about reefs, these papers provide interesting and important insights to our continuing understanding of them. These papers were originally part of a symposium entitled Reef Complexes in Time and Space, held at the annual SEPM meeting in Calgary, June 1970.