Samuel Warren Carey is distinguished for his extensive studies of the geology of Australia and Papua New Guinea. He is particularly noted for his contributions to the theory of plate tectonics. He used his analysis of the geology of PNG to build up a detailed picture of indestructible continental blocks mobile over the surface of the globe. Much later discoveries by others of seafloor spreading and subduction replaced his hypothesis of an expanding earth. He played an important role in advancing this major feature of the dynamics of the earth.