An 1862 graduate of the Sheffield Scientific School at Yale, Clarence King served as a volunteer member of the California Geological Survey from 1863-1867 before receiving an appointment to head the U.S. Geological Exploration of the Fortieth Parallel. With a rising reputation in the discipline, King helped organize the U.S. Geological Survey in 1879, becoming its first director, however he resigned in 1881 to enter into private work as a mining engineer and economic geologist. The King Papers consists of a dozen letters written by King to his colleague and friend Samuel Franklin Emmons, 1873-1894, that are revealing of their personal friendship as well as of the politics of the early organization and management of the U.S. Geological Survey.

One of Philadelphia's most recognized geographers at the turn of the twentieth century, Henry Grier Bryant (1859-1932) was an explorer, traveler, and writer known for an avid interest in the arctic. His financial independence enabled Bryant to devote his life to expanding geographic knowledge, as an officer of the Geographic Society of Philadelphia and Alpine Club of America, and as an explorer and traveler to Labrador, Greenland, the Canadian Rockies, South America, and southern and southeast Asia. The Bryant Letterbooks include an important slice of outgoing correspondence from the geographer and explorer, Henry G. Bryant, documenting his interest in geography and exploration. The four volumes consist of letterpress copies of outgoing correspondence (1884-1890, 1899-1902, 1902-1903, and 1913-1918) concerning personal and financial matters as well as business conducted as an officer of the Geographical Society of Philadelphia and Alpine Club of America. The collection also includes three folders of correspondence addressed to Bryant, 1886-1911, mostly pertaining to the Alpine Club.