He established that the ice ages of the last half million years or so are a cyclic phenomenon. This supported the ideas of Milankovitch and revolutionized ideas about the history of the oceans and the glaciations. He was also the proponent of Project "LOCO" (for Long Cores) to the U.S. National Science Foundation. The project was a success. It gave evidence of the history of the oceans and tested the hypotheses of seafloor spreading and plate tectonics.