born at Newport, graduated from Yale (1862), after which he made a horseback trip across the continent to work in the mines of the Comstock Lode and California. He was next engaged (1866–77) in a geological survey of the Cordilleran ranges from eastern Colorado to California, whose results were published in the cooperative Report of the Geological Exploration of the Fortieth Parallel (7 vols., 1870–80). This is said to have been the most thorough and the most exact government survey published to that date. After heading the U.S. Geological Survey (1878–81), he continued his own important writings on geological and geophysical problems. His most popular work was the series of sketches Mountaineering in the Sierra Nevada (1872), scientifically accurate as well as charmingly descriptive of the region. His ability as an author is further seen in “The Helmet of Mambrino” (Century, May 1886), and in the discussions with his friends John Hay and Henry Adams, which are said to have been partly responsible for the novels The Bread-Winners and Democracy.