The biography of Raphael Pumpelly, a transitional figure in a period of rapid change Raphael Pumpelly: Gentleman Geologist of the Gilded Age provides an excellent opportunity to look at the development of the profession of geology during the years spanned by his career, from 1860 to the early twentieth century. In this period, the practical applications of geology to resource development were of major importance, but geologists were also investigating new subjects, such as petrology, geomorphology, glaciology, and structural geology. These investigations resulted in an explosion of knowledge in these areas and in the growth of subdisciplines. Pumpelly did research in these fields but like others of his generation did not limit himself to any one of them; he remained a generalist in a time of increasing specialization, a transitional figure in a period of rapid change.