Page:U.S. Department of the Interior Annual Report 1876.djvu/25

Rh for the fiscal year of 1876-'77 were available for the continuation of field operations. Daring the time thus indicated a "report on the geology of the Uinta Mountains and a region of country adjacent thereto" was completed, which was accompanied by an atlas, embracing a map of the district, exhibiting the local distribution of geological formations; another, showing, by appropriate colors, the distribution of irrigable lands, timber-lands, grass-lauds, and mineral-lauds, and four sheets devoted to the proper exhibit of the structural geology of the region.

In addition to this work, the necessary computations for the construction of the maps of the region previously surveyed were finished, the projections made, and the drawiugs completed ready for the engraver. In the mean time preliminary maps of the region were prepared and photolithographed.

After completing the report on the Uinta Mountains above mentioned, Professor Powell's time was chiefly occupied in the study of the ethnographic and linguistic materials collected in previous years. As soon as the appropriations for 1876-77 could be used the surveying corps took the field, and five parties were organized—one to continue the triangulation, two topographic parties, and two geological parties—These parties are still in the field. The region surveyed during the present season has been chiefly in the Territory of Utah, but a small part in the northern part of Arizona. The Rocky Mountain region of the United States, (not including Alaska,) or that portion west of the meridian of 99° 30', was by a former Secretary of the Interior divided into districts for surveying and mapping purposes, and these districts numbered; the area of each district is 2½ degrees in longitude, and 1¼ degrees in latitude. The region of country surveyed by the parties under the direction of Professor Powell is embraced in districts numbered 75, 85, 86, 95, 96,104, and 105; the first five lying directly west of the region in which Dr. Hayden is engaged, while districts 104 and 105 lie immediately south of the other districts in which he himself has been at work? During the earlier part of his work, before these districts were established by this Department, Professor Powell's work extended in an oblique direction from northeast to southwest along the general course of the Colorado River through the districts above designated, but the work was in such a condition that no one district was complete. During the present season his parties have been engaged in extending the survey over the unsurveyed fractional districts, so that final and complete maps of each may be constructed.

In addition to the determination of geodetic positions and general geographic features, the system of classifying the lands inaugurated in former years has been continued during the present; the object of this classification being to determine the extent and position of the irrigable lands, timber-lands, grass-lands, mineral-lands, and waste lands, the latter being composed of rugged mountains and desert plains.