HENRY S. WILLIAMS (1847-1918)-THOUGHTS ON EVOLUTION

A native of Ithaca, New York, Williams was educated at Yale University and twice served on the faculty of Cornell University, with ten years as a member of the Yale faculty in between his two faculty years at Cornell. Williams is best known for his work in paleontology and stratigraphy. It was through his efforts that in North America the Carboniferous Period was subdivided into the Mississippian and Pennsylvanian Periods. But also, even though he was a devoted Christian, in his own way Williams was a champion of Darwin's idea of the evolutionary process by natural selection. During his first tenure at Cornell, he began to include more and more Darwinian concepts in his paleontology classes. As he gained more and more knowledge of the fossil record, especially about the Devonian brachiopods of New York, he began to wonder about the rate of evolutionary changes; something that still provides a challenge for us today. His conclusion is found in a set of class lecture notes prepared sometime in the 1880s or 1890s, but no later than 1902; notes that he used in his classes at both Cornell and Yale. In these Williams wrote, "If therefore it be a general law (as I have much reason to believe is actually the case) it could be said truthfully in many cases that genera do arise suddenly, geologically speaking, and not by slow and gradual process of evolution." [Parentheses in the original]. His interpretation appears to have been one of very fast evolutionary change, followed by long periods of stability; an idea currently associated with the term "punctuated equilibria," yet H. S. Williams came to this conclusion at least 100 years ago. The main focus of this paper is the development of the idea by Williams and what he did with it later.