| OCR Text |
Show 21 command of the latter, which is subdivided into three parties. This section of the expedition will disband at Fort Lyon, Colo., and during the season will conclude triangulation- work left incomplete because of the uncertainty of making the best selection of the vertices of a system of triangles in a section of country thickly studded - with mountain- peaks, over which no prior reconnaissance has been made, experienced during the last as well as in preceding seasons. Lieutenant Morrison and party are instructed to fill in a space left blank in the southwestern portion of sheet 69, and search further for a line for a wagon- route leading from the valley of the Arkansas to the headwaters of the Puerco of the West, and thence branching to Northern and Eastern Arizona in the vicinity of Prescott and Camp Apache, most of which has already been determined by officers sent out from the headquarters of the Department of the Missouri, and by parties of this survey. Detailed work extending eastward to the central line of sheet 78 will be carried as far to the south as the time and force will permit. This section, an expedition by itself, is most completely equipped, and good work, and a great deal of it, is expected to result. The California section has been subdivided into five parties. Detailed operations will be completed as far as practicable in sheets 72 and 73. A belt of triangles will be carried along the peaks of the coast and Sierra Nevada ranges as far north and eastward as Death Valley; portions of the outlying basins and their surrounding mountains in the vicinage will be worked up in detail by another party. The special party under Lieutenant Bergland will examine the Colorado River, making special preliminary surveys at the following points: 1st, foot of Virgin Canon; 2d, mouth of Rio Virgen; 3d, mouth of Vegas Wash 5 4th, near Cottonwood Island 5 5th, Camp Mohave; 6th, in the vicinity of the " Needles." The flow of the river and the character of its sediments will be determined at the mouth of the Rio Virgen and at Camp Mohave. The character of the soil in the vicinity of the above- named places, and along the routes to and from their field of labor, will be carefully noted. An approximate estimate of the cost of a canal leading from any of the above points, if one feasible can be found, with the preliminary location of its line, will be made. The above are a number of the subjects from which results are expected to be obtained during the short field-season that they will be required to labor in that hot and now comparatively desert region. This special survey, if carried forward to completion, implies other examinations than those necessary to prove its practicability as an engineering problem, and involving detailed investigations into the present physical condition, the climatic, and other oscillations, with attendant hygrometric and surface changes in this great area of drainage; and, in view of the limited means available, no more than a preliminary examination, arranging in skeleton the accumulation of existing facts, and those made known by the labors of this season, can be expected. A report of their results will be communicated at an early day, after their return from the field, October 15, and also a detailed estimate of the time and means necessary to determine with certainty the possibility of the diversion of the Colorado for purposes of irrigation at any point along its present channel between the foot of the Grand Canon and its entrance into Mexican territory at the boundary, below Fort Yuma, Cal.; it having been demonstrated by results already obtained that such |
