His students made important advances in a variety of subjects, including alluvial chronology, periglacial and glacial geology, wind action, soil and vegetative effects on landscape development, and archaeology. His influence is indicated by the fact that of the four geologists who have received the National Medal of Science, three were students of Kirk Bryan.〔Leopold did not provide a list of the National Medal of Science winners to whom he referred, and his meaning is not apparent. Earth scientists in addition to Leopold who had received the National Medal of Science at the time of this statement include geochemist Wallace S. Broecker, oceanographer Walter Munk, geophysicist Frank Press, oceanographer Roger Revelle, geologist William Rubey, planetary geologist Eugene Shoemaker, meteorologist Verner Suomi, geophysicist George Wetherill, and geographer Gilbert F. White. None of these men's biographies (other than Leopold's) suggest that they ever studied formally under Bryan, although several may have collaborated with him.〕