On the basis of all available piston and DSDP cores taken from the seafloor around Iceland an attempt is made to establish a history of major explosive North Atlantic Cenozoic volcanism from the distribution of volcanic ash layers. The earliest sediment reached is early Eocene. After interpolating for missing data and correcting for effects of prevailing winds and regional plate tectonics, the analysis provides an estimate of the rate of explosive Cenozoic volcanism. Two epochs appear outstanding in rates of volcanism; middle Eocene shows the highesat rate, and Pliocene, next highest, has about half the Eocene rate. These are followed in decreasing order by Pleistocene, Miocene, and Oligocene. The analysis further suggests that the Cenozoic ash layers originated in subaerial volcanism related to the growth of Iceland.