LATE 19th CENTURY PETROLOGY, INCLUDING GRANITIZATION AND CIPW, IN SOCIAL CONTEXT

George Huntington Williams, first Professor of Geology at the Johns Hopkins University, was born (1856) in Utica, New York, of a father who became a prosperous banker. His mother’s maiden name was Doolittle. A male relative, born in the year after Williams, had the first name, Dana. Two leading geologists of the 19^th century, James Dwight Dana (1813-1895) and Charles Doolittle Walcott (1850-1927), were natives of the Utica area. Professor Williams published most of his important papers in the American Journal of Science, which Dana edited, or as reports of the U.S. Geological Survey (USGS), of which Walcott became Director a few days before Williams died. Williams died on 12 July 1894 in Utica of typhoid which he probably contracted from drinking contaminated well water in the Rock Creek valley, just north of the District of Columbia.

Publications of Dana and Williams, and annotations by Williams on the printed publications of Dana, indicate that into the 1880s, Dana favored granitization as the mode of origin for igneous and metamorphic rocks, and Williams believed that pressure and temperature, almost independent of composition, determined those rocks. Dana’s published work at the end of his life resembled more that now would be igneous petrology.

The CIPW classification of igneous rocks started in the late 19^th century, became codified in early 20^th century, and is still used into the 21^st century. CIPW is the 20^th century acronym for Cross, Iddings, Pirsson, and Washington – four petrologists in alphabetic and chronologic (by birth) orders. As implied in Davis Young (2003, 2009), Williams functioned as the first W in the acronym, but he died before the formulation of normative CIPW calculations. These five petrologists had remarkably similar histories: all born between 1854 and 1867; three of the five graduated from Yale and the other two (including Williams) from Amherst; all studied in Germany, three of the five (including Williams) at Heidelberg under Rosenbusch, each learning the German petrography and petrology of the day. The similarity likely extended to their families’ wealth that provided extended study and travel in Europe and independence in their employment. These results depend on information in the Department of Rare Books and Manuscripts, Sheridan Libraries, of the Johns Hopkins University.