Page:U.S. Department of the Interior Annual Report 1876.djvu/24

XX GEOLOGICAL AND GEOGRAPHICAL SURVEY. FIRST DIVISION.

The United States Geological and Geographical Survey of the Territories, under the direction of Professor Hayden, during the brief season of 1876, continued its work in Colorado, completing the western and northwestern portions, including a considerable portion of Eastern Utah, embracing an area of about 10,000 square miles.

The areas of exploration were much farther from the base of supplies than heretofore, being located in the remote interior of the continent, and at times infested with roving bands of hostile Indians. On this account the difficulties were much increased, causing great loss of time in traveling to and from the fields of labor.

The survey the present season was divided into five parties, four of them for topographical and geological work, and a fifth for making collections in natural history.

The topographical as well as the geological structure of the areas surveyed the present season was of the highest interest. It has been called the plateau region, and all the drainage extends westward into the Colorado River, and the streams, with their numerous branches, have worn deep gorges or canons into the crust of the earth four thousand feet or more in depth. Continuous sections of strata were thus exposed nearly a vertical mile in thickness, rendering the geology simple and expressive.

Six sheets of the physical atlas have now been completed in accordance with previous instructions from the Department of the Interior, and the engraving is nearly done, and that portion of the physical atlas embracing Colorado and parts of the adjacent Territories will be ready for distribution early in the spring. Each of the sheets embraces an area of over 11,500 square miles, with a total area of about 70,000 square miles. They are prepared on a scale of four miles to one inch, with contours of two hundred feet, and on these charts will be represented, by means of colors, the geological formations, as well as a great amount of valuable information of a practical character to the country in regard to the areas of grass, timber, and mineral lauds, and all those portions susceptible of cultivation by means of irrigation. Much information was also secured in regard to the ancient ruins of Southern Colorado, New Mexico, and Utah, and large collections of minerals, fossils, and other specimens of natural history. None of the parties were disturbed by hostile Indians, and the results of the season's labor are very satisfactory.

SECOND DIVISION.

The work of the geographical and geological survey of the Rocky Mountain region, under the direction of Prof. J. W. Powell, during the past year, will, it is believed, show practical and important results. On the arrival of the parties from the field late in the fall of 1875 work in the office was promptly organized and pushed with all possible vigor through the winter, spring, and early summer, until the