The first chair of the department, Oliver C. Farrington, came to the Museum at the time of its founding in 1893. Farrington built the collections into worldwide importance during his tenure. Elmer S. Riggs, appointed shortly after The Field Museum's opening, became the first paleontology curator, and assembled the nucleus of the vertebrate paleontology collections. Riggs collected many dinosaurs from the Rocky Mountain states and Canada, and led several expeditions to South America where he amassed an outstanding Cenozoic mammal collection. Henry W. Nichols, the second chair, specialized in mineralogy. He was followed by Sharat K. Roy, who studied in his native India, London, and Illinois, and led a number of museum expeditions, including those to Baffin Land and Labrador in 1927-1928. Bryan Patterson, on staff from 1926 to 1955, published extensively on Riggs' collection of South American fossil mammals, and made several major collections in the United States, including those from the Piceance Basin, one of the first significant Paleocene fossil vertebrate faunas. His collection and studies on the Trinity Cretaceous mammals of "metatherian-eutherian grade" from north Texas was a major contribution to mammalian paleontology. Rainer Zangerl became head of the department in 1962 after serving seventeen years as curator of fossil reptiles. Zangerl extended his interest to Pennsylvanian paleoecology, and co-authored (with Eugene Richardson) a now classic memoir on paleoecology of Pennsylvanian black shales. Zangerl was succeeded in 1974 by Edward J. Olsen, who came to the museum in 1960 after teaching at Case Institute of Technology and Western Reserve. David M. Raup joined the geology staff as department chair in 1978, following faculty positions at the California Institute of Technology, Johns Hopkins, the University of Rochester, and the University of Chicago. John R. Bolt became department chair in 1981, following a period in which Bertram G. Woodland was acting chair. Bolt received his doctorate from the University of Chicago, and joined the Museum in 1972 after several years of teaching at the University of Illinois at Chicago. Peter R. Crane joined the Department in 1982 and served as Chair from 1990-1992 before taking a more senior administrative position. The current chair, John J. Flynn, joined Field Museum's geology staff in January, 1988, following several years as a professor in the Department of Geological Sciences at Rutgers University.