1854 - 1944
The department of geoscientific studies at Princeton University dates from 1854, when Arnold Guyot was appointed by the College of New Jersey as Professor of Geography and Physical Geology. Guyot, formerly a professor at the University of Neuchatel, left Switzerland in the wake of the revolution of 1848, and lectured at Cambridge, Mass., before joining the College (formally renamed Princeton University in 1896). Guyot would remain the sole instructor in geological sciences for the next 19 years. In that time, he was largely responsible for the genesis of the Geological Museum (currently housed in the building which bears his name), which grew out of the fossils and geological specimens he collected for instructional purposes. In 1873, Dr. Franklin C. Hill, the first addition to the proto-department, became Curator of the Geological Museum, then located in Nassau Hall. Also in that year the John C. Green School of Science was founded, bringing with it the appointment of Dr. Henry R. Cornwall as Professor of Analytical Chemistry and Mineralogy.

From its earliest years, the department was a leader in geological and paleontological fieldwork. In 1877, three of Guyot's students - William Berryman Scott, Henry F. Osborn and Francis Speer - participated in the first Princeton field expedition to Colorado and Wyoming for the purpose of collecting vertebrate fossils - no small undertaking since significant portions of the area were as yet unsettled. It was the inaugural expedition in a series of field trips to the American west made by Princeton students and faculty, eight of which Scott himself would lead between 1882-1893. Scott was later awarded the Blair Professorship of Geology and Paleontology (1884), the department chair (1904-1930), and introduced to the University a two-part course on evolution, a subject on which he published. Another important addition to the growing program in earth sciences came in 1882 with the appointment of William Libbey as Professor of Physical Geography. In 1880, Libbey had served as Guyot's assistant and later was the first student to receive the doctoral degree in science at Princeton.

Libbey also conducted extensive fieldwork and geographical exploration; among his travels was an attempted ascent of Mt. St. Elias in Alaska (1888), as well as two journeys to Greenland, first as geographer of the Peary Auxiliary Expedition (1894) and again as the leader of the Princeton scientific party on the Peary Club's relief ship (1899). His spectroscopal analysis of the gasses at Kilauea was the first detection of hydrogen in those emissions. Despite the growth of geological and paleontological studies at Princeton in the mid- to late 19th century, there were no formally discrete departments or sections in geosciences until the early 1880's when concentrations in "Physical Geography" and "Geological Paleontology" were introduced.

The turn of the century, however, saw a reorganization of University departments, resulting in the creation of a single Department of Geology (1904). The succeeding five years were to be a period of considerable growth for the department. New groups of undergraduate and graduate courses were adopted, including Stratigraphy, Petrology, Chemical Geology and Vertebrate Paleontology, among others. Also in the century's first decade, the University established its Graduate School as a separate organization; no systematic program of study had formerly existed on the graduate or post-graduate level, and the three doctorates in science that had been conferred to this point were on the basis of research merit. The end of this eventful decade saw the relocation of the Geology Department from its former quarters in Nassau Hall to the newly-constructed Guyot Hall (1909). Still home to the present Geosciences Department, Guyot Hall was designed by departmental members and funded by the mother of Cleveland H. Dodge (1879), a University trustee. The stone carvings adorning the exterior of the building are thought to have been the work of the studio of Gutzon Borglum, the sculptor who created the presidential effegies of Mt. Rushmore.

The department (and the University in general) experienced a second period of growth during the 1920's, leading to the acquisition of more faculty and expanded course offerings, as well as new opportunities in fieldwork. In 1926, Richard M. Field organized Princeton's Summer School of Geology and Natural Resources, a yearly field course designed to train students in techniques of geological and geophysical research. The summer program, still extant, is currently listed in the departmental course offerings as GEO 311. In the following year, the University received funds to endow the Knox Taylor Professorship of Geography, awarded first to Professor Paul MacClintock, formerly of the University of Chicago. Another key figure in the development of the department at this time was Alexander .H. Phillips, whose work on the role of trace metals in the life processes of marine organisms and the extraction of radium from Colorado carnotite were significant advances in his field.

The economic depression of the 1930's brought about a temporary reduction of department personnel, but did not prevent the organization of an unprecedented array of Princeton-led field projects in geosciences. Among these were a series of expeditions to Newfoundland beginning in 1932 under the direction of faculty member A.K. Snelgrove. The field work was jointly conducted by faculty, graduate and undergraduate students, encompassing several projects in different parts of the island. Snelgrove was subsequently appointed by the Newfoundland Government to direct the Newfoundland Geological Survey, a post which he held simultaneously with his professorship at Princeton. This led to a cooperative and long-lasting relationship between the Survey and Princeton's Department of Geology.

Another major undertaking in field research at this time was the "Red Lodge Project" (1930), initiated by Richard M. Field and fellow faculty member W. Taylor Thom. Red Lodge and its successor, the Yellowstone-Bighorn Research Association (1936), were designed to further geological knowledge both in general and about that region in particular. In the tradition of Field's "Summer School" program, one of the project goals was to provide a favorable field situation for the training of students. Red Lodge and YBRA proved to be highly successful; by 1941 over 44 colleges and universities had been represented in these projects by faculty, graduate and undergraduate students. Although he would remain active with Red Lodge, Field went on to conduct measurements of gravitational anomalies in the Caribbean, marking a significant chapter in Princeton's long-standing involvement in the study of that region's geology.

In 1932, Field recruited Harry Hammond Hess, then only a few months away from his Ph.D., to assist in the research. After Hess took his doctorate, he joined the department faculty, succeeding Alexander Phillips in 1934 as Professor of Mineralogy and later serving as department chair from 1950-66. Hess remained actively interested in ocean basin research throughout his entire career; after the Second World War, his continued work in this field would eventually lead to his ground-breaking theory of sea floor spreading, which contributed significantly to the understanding of plate tectonics and continental movement.

In 1942, the entry of the United States into the Second World War prompted the University to adopt an accelerated study program, allowing its students to complete their coursework within three years or less. In spite of this, the Department of Geology saw a marked decrease in enrollment as more and more students interrupted their studies to enter the armed services or undertake work otherwise related to the war effort. An even sharper decrease in department faculty necessitated special courses during the Winter Reading Period, doubled enrollment for several classes and field expeditions, and a larger program of study for the summer term. The department also responded to the national crisis by adopting courses specifically designed for military purposes, particularly army topography and the interpretation of arial reconaissance photography. These were offered to a group of students largely composed of enlisted men. The war had many long-lasting effects on the department, not the least of which was an increased awareness of the importance of instruction in the relationships between geosciences and culture, global economics and public policy.

1945 - Present
In the decade following the Second World War, the department faced new challenges as increased graduate enrollment put greater demands on the still-diminished faculty. The retirement of veteran professors Field, Thom, and MacClintock (among others) within a relatively brief span of time amplified the necessity of bringing new and reputable instructors to the University's geosciences team. Hess, then department chairman, always remained acutely sensitive to the high demands of the department in the credentials and capabilities of incoming faculty, and recognized that despite the difficulties of the existing workload, they could not afford to compromise on the quality of their instructors. The boom in technological progress occasioned by the war also put severe demands on the available space for scientific equipment in Guyot Hall, while the eventual increase in the number of faculty restricted available office and classroom space. The shortage would not be rectified until 1959, when ground was broken for a new building for the Biology Department adjacent to Guyot Hall, freeing up considerable space in Guyot formerly occupied by Biology personnel.