The President of the American Geophysical Union from 1948 to 1953 specialized in zoology as an undergraduate and received his doctorate in paleontology, although he is best known for his work in sedimentation and structural geology. Perhaps the election of a man with this background was a harbinger of things to come, since recent findings in geology and geophysics have led to a model of the earth in which it is apparent that the data from seismology, paleontology, paleomagnetism, sedimentology, geochemistry, structural geology, and other subdisciplines of the earth sciences are related in a very intimate way.

Before his death in 1965 this man, Walter Bucher, wrote a paper entitled ‘The Third Confrontation’ in which he recognized that the earth sciences were in for a major upheaval. Bucher noted that twice before there had been major confrontations between geologists and geophysicists. The first, in 1899, came when Kelvin estimated the age of the earth to be between 20 and 40 m.y., a concept that was distressing to geologists and paleontologists. The second, early in this century, concerned the origin of ocean basins, which, in the eyes of the foremost geologists of the day, were sunken or collapsed continents. This concept was geophysically unappealing.