48 REPORT OF THE SECRETARY. 



First Lieut. George M. Wheeler, Corps of Engineers,ITnited States Army, 

 and reporting to Congress through the Engineer Bureau of the War 

 Department, were begun in 1869. In that year the present officer in 

 charge, while making reconnaissances for routes of communication 

 through Southern Nevada, conceived the idea of extending the work to 

 other portions of the Military Department of California. A plan for 

 the prosecution of the same was presented while elaborating the results 

 of that year's work. Lack of funds prevented operations in 1870, but 

 in 1871 parties again took the field in Nevada, California, and Arizona. 



At that time the work received its principal support from the appro- 

 priation for " Surveys for Military Defenses," under which head it nat- 

 urally fell. In 1872, however, Congress appropriated special means and 

 a more complete organization was made, the survey being prosecuted 

 principally in Utah, but also in Arizona and Southeastern Nevada. In 

 1873 the character of the methods employed upon this work advanced 

 in proportion with the prospect of its development into an accurate 

 geodetic survey, extending over large areas. During this season many 

 points accessible to the telegraph were occupied for completing the sys- 

 tem, now extending from Eastern California, Nevada, and Northern Ar- 

 izona to the eastern base of the Eocky Mountains. In 1874, connection 

 between the east and west portions was made more perfect. In 1875. 

 the operations of the survey were conducted in two divisions, designated 

 as the California and Colorado sections, the former acting in portions of 

 the southern sierras and extending from the branches of the coast- 

 ranges south of latitude 37°, eastward toward the Colorado desert, 

 while the latter expanded the finished area of 1873 and 1874 in Colo- 

 rado and New Mexico. 



The distribution of areas surveyed thus far is as follows : 



Square miles. 



In Nevada ..... ..',' ..58,940 



In California 40, 625 



In Arizona «. 60, 120 



In Colorado 37, 550 



In Utah 44, 015 



In New Mexico 53, 236 



The maps issued to date cover areas as follows : 



Square miles. 



On a scale of 1 inch, to 8 miles 192, 217 



On a scale of 1 inch to 4 miles - : 13, 028 



On a scale of 1 inch to 2 miles 1, 091 



During the season of 1875 one party of the California section contin- 

 ued examinations for determining the practicability of diverting the 

 Colorado Eiver for the purpose of irrigation. The report of Lieutenant 

 Bergland on this subject, and the information already submitted by the 

 officer in charge of the survey, are sufficiently full to place this matter 

 at rest for the present. 



