608 REPORT OF NATIONAL MUSEUM, 1904. 



traversed by the Pacific Railroad. The region explored, however, 

 was a very extended one, reaching from the eastern Colorado range to 

 the Sierra Nevadas, with an average width of about 100 miles along 

 the fortieth parallel. 



» The plan of the work, as outlined by Emmons," contemplated making 

 a topographical map of the region on the general plan of those made 

 at the present time, i. e., one on which the topography was indicated 

 by contour lines rather than hachures on the hillsides, the then pre- 

 vailing custom. The scale adopted was 4 miles to the inch, and the 

 original area divided into three rectangular blocks or atlas sheets, each 

 about 165 miles in length by 100 miles in width. " Subsequently two 

 more blocks were surveyed, making the total area surve}ed and 

 mapped some 82,500 square miles. 



The party, according to the author above quoted, rendezvoused in 

 California in the early part of the summer of 1867, and began their 

 work at the east base of the Sierras in August, with J. D. Hague, 

 Arnold Hague, and S. F. Emmons as geological assistants. Though 

 tew in number, the force was beyond question the best equipped of 

 any that had thus far entered the field of American geology. 



The winter of 1867-68 was spent at Virginia City, Nevada, in the 

 stud} 7 of the Comstock Lode, the mines of which, then but 1,000 feet 

 in depth, had already produced some one hundred millions of dollars. 

 The results of this work appeared in J. D. Hague's monograph, The 

 Mining Industry, published in 1870. 



During the season of 1868 the work of the survey was pushed east- 

 ward entirely across the Great Basin to the western shore of Great 

 Salt Lake. In that of 1869 the desert ranges of Utah, the Wasatch, 

 and the western end of the Uinta ranges were surveyed. This com- 

 pleted the work as originally planned, and with headquarters at New 

 Haven, the task of working up the collections and platting the topo- 

 graphic and geologic notes was undertaken. 



This work was, however, abruptly interrupted in the summer of 

 1870 by telegraphic orders from General Humphrey, directing the 

 party to once more take the field, Congress, without solicitation, hav- 

 ing appropriated money for the continuation of the survey. It being 

 then too late in the season to prepare the necessary outfit for work in 

 the high mountain regions east of the Wasatch, the season was devoted 

 to a study of the extinct volcanoes, Mount Shasta, Mount Rainier, 

 and Mount Hood. Among the results of this study was the discoveiy 

 of the first-known active glaciers within the limits of the United 

 States. 



During the summers of 1871-72 the survey was carried eastward to 

 the Great Plains and included an examination of the Eocene beds of 



« Presidential Address, Geological Society of Washington, 1896. 



