The King Survey was a smaller organization, with Congressional authorization of definite scope and a systematic plan of operation. The beginning of construction of the Union Pacific terminated the period of the railroad surveys under the War Department and afforded opportunity for geologic work that would be more than exploratory: the opening up of the new country made investigation of its resources logical. This fact was recognized by Clarence King, who had traversed the same route as a member of an emigrant train with his friend James T. Gardner. His plan to make a geological cross section of the Cordilleras, with a study of the resources along the route of the Pacific railroads, won the support of Congress, and the “Geological Exploration of the Fortieth Parallel” was authorized in 1867, with Clarence King as geologist in charge, under the Chief of Engineers of the Army. Field work was begun in the summer of that year, and it is interesting to note that Mr. King and his small force of geological assistants—the two Hagues and S. F. Emmons—began at the western end of this cross section, and in this and subsequent years extended the survey from the east front of the Sierra Nevada to Cheyenne, covering a belt of territory about 100 miles in width. This comprehensive plan was carried out in the field operations, and the scientific and economic results were systematically worked up in the reports, which appeared in 1870–80. The only departure from this plan was a study of the volcanic mountains Shasta, Rainier, and Hood, in 1870, occasioned by an unexpected and unsolicited appropriation for field work, and that summer’s work resulted in the discovery of active glaciers, the first known within the United States.