Thomas C. (Thomas Chrowder) Chamberlin

Born in Mattoon, Illinois, on September 25, 1843, Thomas Chrowder Chamberlin became one of the most influential American geologists of his era. He taught at Beloit College, worked with the Wisconsin Geological Survey, and later served as president of the University of Wisconsin before moving to the new University of Chicago, where he built its geology department.

Chamberlin is especially remembered for his work on glacial geology and for encouraging scientists to test multiple possible explanations rather than settling too quickly on a single answer. He also founded the Journal of Geology in 1893 and remained an important voice in American science for decades.

His interests ranged far beyond rocks and ice. Chamberlin wrote about the age of the Earth, past climates, and planetary origins, and he became widely known for the planetesimal hypothesis, developed with astronomer Forest Ray Moulton, which offered a new way to think about how the solar system formed. He died in Chicago on November 15, 1928.