LETTEE. 9 



was extended into the Territory of Wyoming, along tlie line of the 

 Union Pacific Eailroad. A second annual report was made as the re- 

 sult of this brief preliminary examination. But it was not until the 

 spring of 1869 that the survey received its present form. At the close 

 of the session a clause was added to the sundry civil bill, in the follow- 

 ing words, " For the continuation of the geological survey of the Terri- 

 tories of the United States, by Prof. F. Y. Hayden, ten thousand dollars, 

 to be expended under the direction of the Secretary of the Interior." 

 By direction of the Secretary of the Interior a geological reconnaissance 

 was extended along the eastern portion of the Eocky Mountain range, 

 from Cheyenne to Santa ¥6, N. Mex., and in the winter of 1869-70 an 

 annual report was published containing the preliminary results. In 1870 

 the appropriation was increased to $25,000, and the season was occupied 

 in exploring portions of Wyoming Territory. In 1871 $40,000 was ap- 

 propriated for the continuation of the survey, and by direction of the 

 Secretary of the Interior the work transferred to the interesting region 

 about the head-waters of the Yellowstone and Missouri Elvers. To this 

 expedition one topographer was attached. 



In 1872 the work was continued in that region, with an increased ap- 

 propriation of $75,000, with two large parties and a full corj)s of 

 topographers and geologists. The result was a still more detailed ex- 

 ploration of previously little-known portions of Montana and Idaho, 

 especially about the sources of the Yellowstone, Missouri, and Snake 

 Elvers. A preliminary account of the results of the survey was given 

 in the annual report for 1872. 



During the season of 1873 the geographical, as well as the geological, 

 corps was more complete and better prepared for its duties than at any 

 previous period. The Territory of Colorado was assigned to it as the 

 field of its labors ; and the report of progress, which contains many of 

 the important results, is now ready for publication. 



THE PUBLICATIONS OF THE SURVEY. 



The plan of publication of the results of the survey has been matured 

 gradually, and it is believed that it meets the requirements of the scien- 

 tific men of the country, as well as the people at large. The publica- 

 tions are divided into three principal classes. 



The first class consists of the annual reports, or reports of progress. 

 These will be issued every year, and will give early information of the 

 progress of each season's labors. They will contain much new and im- 

 portant matter. 



The second class comprises a series of "miscellaneous publications" 

 on different subjects connected with the West, which are important contri- 

 butions, but are to some extent compilations, and usually issued in smaller 

 editions. They consist of elevations, meteorological observations, ac- 

 counts of the botany, ornithology, entomologj^, catalogues, &c.; all based 

 on the labors of the survey. 



