Grove Karl Gilbert

Grove Karl Gilbert 1843-1918, American geologist, b. Rochester, N.Y., grad. Univ. of Rochester, 1862. When the U.S. Geological Survey was created in the Dept. of the Interior in 1879 (to replace four surveys in the Dept. of the Interior and the Dept. of War), Gilbert was appointed senior geologist. His Report on the Geology of the Henry Mountains (U.S. Geographical and Geological Survey of the Rocky Mountain Region, 1877, 2d ed. 1880) contains the first description of a laccolithic mountain group, a form of mountain structure that he was the first to recognize and explain. The report introduced concepts of erosion, river development, and glaciation that are incorporated in modern theories of physical geology. One of the publications of the Geological Survey is Gilbert's Lake Bonneville (1890), a study of the ancient lake of which Great Salt Lake is the remnant. He mapped the ancient shores and outlets of the Great Lakes and was the first to recognize that the successive levels of the lakes were caused by the barrier of the receding glacier, which cut off the natural drainage of the region. He also published notable studies on Niagara Falls and the Niagara River, the glaciation and morphology of the Sierra Nevada, and hydraulic mining debris in the Sierra Nevada. In 1899 he accompanied the Harriman Alaskan expedition and wrote the volume Glaciers and Glaciation in its reports.

Bibliography: See biography by W. M. Davis in the Memoirs of the National Academy of Sciences, Vol. XXI (1926).

Gilbert, Grove Karl (1843–1918) An officer on the US Geological Survey, Gilbert made studies of Meteor Crater, Arizona, suggesting that it was the product of a collision with an asteroid, and also studied lunar craters. He investigated crustal movements around Lake Bonneville, developing a theory of crustal isostatic compensation (see ISOSTASY). He also distinguished between folded and block-faulted mountains.

Gilbert, G. K. (1843–1918) Grove Karl Gilbert is widely regarded as the most accomplished American geologist. After early experience with the Ohio, Wheeler, and Powell Surveys, he was one of the six original geologists hired in 1879 to the US Geological Survey. By 1888, he had risen to Chief Geologist, and his professional career was fully linked to the Survey. Gilbert received many honours in his own time, including the distinction of being the only person ever to serve twice as president of the Geological Society of America.

Gilbert is best known for the exemplary quality of his scientific monographs. As a member of the Powell Survey, he produced the 150-page Report on the geology of the Henry Mountains. In his structural analysis of the Henry Mountain laccoliths, Gilbert used quantitative mechanical procedures that anticipated the geodynamical modelling of today. Similarly, his analysis of erosional processes relied upon principles of energy and equilibrium in the operation of streams. These themes were continued in later works. His 1890 Lake Bonneville (US Geological Survey Monograph No. 1) was one of the consummate works of nineteenth-century geology. Not only did he describe the dynamics of lake shoreline formation; he showed how warping of the potential surface evidenced in the shorelines could be interpreted in terms of Earth's crustal dynamics. Later works, The transportation of debris by running water (1914) and hydraulic-mining debris of the Sierra Nevada (1917), are classics of fluvial geomorphology.

Gilbert believed that ‘the inculcation of scientific method’ was best achieved by example. In an 1885 Presidential Address to the American Society of Naturalists in Boston, he emphasized the role of hypothesis generation in geology. He proposed that scientific investigators, whom he contrasted with ‘theorists’, generated hypotheses via a creative process of reasoning via analogy. In a 1896 paper entitled ‘The origin of hypotheses, illustrated by a discussion of a topographic problem’, Gilbert expanded upon these views, equating the method of hypotheses to the method of science. In their quest to determine the antecedent causes of phenomena in evidence via their consequences, geologists must first make a kind of guess, to frame a hypothesis, that must then be evaluated for comparison of its deduced consequences against newly discovered facts. Although this pragmatic view of scientific method was shared by contemporaries such as T. C. Chamberlain, it was ignored by twentieth-century philosophers of science, who dismissed the ‘logic of discovery’ as unworthy of serious logical inquiry. Nevertheless, the respect accorded to Gilbert's methodology by practising Earth scientists continues to stand in sharp contrast to their general apathy in regard to the ideas of modern philosophers.

Victor R. Baker