OCR Text |
Show 7 and all possible means employed to bring its labors to the highest practical standard attainable. TOPOGRAPHY. The duties in this branch for the field- season of 1S72 were carried on by two main field- parties, each of which was again subdivided. The area covered, amounting to a little more than 50,000 square miles, lies, for the most part, in western and southwestern Utah ; parts of eastern and southeastern Nevada; northern and northwestern Arizona. The work connects with the survey of the fortieth parallel on the north, occupies portions of the great Salt Lake, Sevier Lake, and other interior basins, and of the valley and basin of the Colorado, in and around the lower of the main or grand cations. Connection was also made with the surveys of 1869 and 1871, aud the area was found to be well distributed in regard to the filling out on the map of: the atlas sheets, numbered 2, 9,16, 3,10, and 17. The area of the 1872 survey had been traversed in several directions by the following of our early explorers: Bonneville, in 1834; Fremont, in 1844; Stansbury, in 1849; Gunnison, in 1853: Beckwith, in 1854; and Simpson, in 1859; whose results have been embodied on the United States Engineer Map of the Western States and Territories. The survey for a special contour map of the Eli mining district, Nevada, was made, and more time taken in the gathering of minute topographical data in the vicinity of the several mining districts. The rule of making the survey more perfect in localities abounding in the precious and economic minerals, t) r where other subjects of practical importance are found, has been strictly followed, and was frequently applied during the season of 1872 in Utah, where the developments in regard to mineral exposure are both varied and complete. The survey for 1872 has furnished complete and connected profiles from Salt Lake, in Utah, to the vicinity of Prescott, in Arizona, and a feasible route can be easily selected that, in a short time, can be rendered highly useful for mail communication, transportation of Government supplies, and the interior passage of troops in changes of station, or other military movements. A report in detail upon this subject appears in the progress report for 1872, in which document also the subject of irrigation in its application to agricultural, mining, and grazing purposes will be treated, and the probable practical points mentioned where water is likely to be obtained by artesian boring. The parties, thoroughly organized for the season of 1873, have already taken the field. Main party No. 2, under Lieutenant Hoxie, starting from the vicinity of Salt Lake, accomplishing certain unfinished areas in sheets Nos. 3 and 10, and then, crossing the Colorado, joins the southern part of the survey. Main party No. 3, in charge of Lieutenant Marshall, took their departure from Denver, and for the greater part of the season will operate in the southwestern portion of Colorado, below the latitude of Denver. Main party No. 1, under my own direction, moves from the vicinity of Santa F6, and constitutes the southern brauch of the survey for this year, occupying areas mostly in Eastern Arizona and Western New Mexico. These parties all converge at Fort YVingate, N. Mex., for disbanding in the fall. A special triangulation- party carry a system of triangles from the meridian of the astronomical station established at Santa F6, west to the one hundred and ninth meridian of west longitude, and thence south to the thirty- second parallel of north latitude. The parties are early in the field, and fruitful results may be expected. The office- work upon the maps continues while operations are going |