Davis, William Morris (1850-1934)

Davis, William Morris (1850-1934)

American geologist

William Morris Davis was a geographer, meteorologist, and geologist who devised a relative method of determining the age of a river system. Davis' method of landscape analysis considered the cyclical nature of erosion and the subsequent uplift of the surrounding land in order to determine the age of the river in relation to its surroundings.

Davis was born in Philadelphia, Pennsylvania into the city's social elite. His grandmother was Lucretia Mott, the famous abolitionist. William Morris Davis bore the name of his uncle, a congressman. Davis spent many of his childhood summers in the farmlands of Pennsylvania, which instilled in him a deep interest in natural history. This interest spurred Davis to study at the Lawrence Scientific School of Harvard University. After his graduation in 1869, he pursued a master's degree in mining engineering, also at Harvard. Davis embarked on a tour of the mining districts of the Lake Superior region with Raphael Pumpelly during the summer of 1869. Later in the same summer, Davis helped Josiah Dwight Whitney conduct fieldwork in the Rocky Mountains. In 1870, Davis accompanied one of his former teachers, Benjamin Gould, to Argentina for the purpose of organizing an astronomical observatory. Davis remained in Cordoba for two and a half years assisting Gould with the observatory and undertaking meteorological work. Davis then returned to Philadelphia after experiencing differences with Gould.

Davis later became an instructor at Harvard, but initially struggled to interest his students. He commenced a lifelong career in research and writing in 1882. In the 1880s, Davis received notice for his work in geology and meteorology , but was internationally known for his research in physical geography . Davis turned out many articles on the Triassic formation of the Connecticut River Valley and on meteorological topics. In 1889, Davis wrote a paper on "The Rivers and Valleys of Pennsylvania." In this paper, Davis introduced the cycle for river system formations that was reiterated in many more of his works. Davis believed that running water is the single most important agent in creating landscapes. At the beginning of his erosion cycle, rivers are small, shallow streams, the result of imperfect drainage of the surrounding topography . With time, the streams carve out deeper channels, widen, and contributing tributaries form. These tributaries, in turn, bring in more and more water creating larger, more powerful waterways. Waterfalls are caused by the contrast of hardness of the rocks as they are worn back. Side-streams then form their own valleys and the valley slopes increase as more soil is carried downstream. At maturity, the river has a system of headwater branches that gnaw at the uplands, which in turn widen the rivers. The surrounding mountains then slowly erode over time. This erosion deposits a large amount of sediment into the rivers. This causes the rivers to become increasingly sluggish and the tributaries dwindle as the flow of water slows. The cycle then begins again when another episode of uplift rejuvenates the river systems. Davis, who was influenced by the English scientist Charles Darwin's organic evolutionary theories, determined the relative age of the river system by discerning its place in the erosion cycle and thus, proposed a cyclical nature to the evolution of the landscape.

Davis published the textbook, Elementary Meteorology (1894), which was widely used in colleges. Other relevant scientific literature published by Davis includes: Elementary Physical Geography (1902), Geographical Essays (1909), The Lesser Antilles (1926), and The Coral Reef Problem (1928). In The Coral Reef Problem, Davis endorsed both James Dwight Dana's and Darwin's belief that barriers such as atolls and reefs are the result from the slow subsidence of the ocean bottom under the upward growing formations of islands.

Davis was appointed Sturgis-Hooper Professor of geology at Harvard in 1898. He retained this position until his retirement in 1912. Davis founded the Association of American Geographers in 1904. He also played a major role in the Geological Society of America. In 1928, Davis, a widower, married his third wife and settled in Pasadena, California where he peacefully lived out his final years until his death in 1934.

See also Landscape evolution