His twin brother David Williams also became a geologist. References and sources References Sources Alexander R. McBirney, Rock Stars: The Father of Modern Volcanology: Howel Williams (1898–1980), GSA TODAY, August 2000 Howel Williams (1898-1980), In Memoriam written by A. Pabst, I. S. E. Carmichael, L. Constance, and G. H. Curtis, Earth & Planetary Science, University of California, Berkeley 20th-century American geologists Members of the United States National Academy of Sciences American volcanologists 1980 deaths 1898 births