cviii GENERAL SUMMARY OF SCIENTIFIC AND 



United States Commission in 1873 and 1874, and had unusual facil- 

 ities in making collections in Natural History and Botany. These 

 collections are now deposited in the Smithsonian Institution, and 

 his rej)ort will form a separate volume. 



The labors of the parties belonging to the " Geographical Survey 

 of the Territories," under the direction of Professor F, V. Hayden, 

 . during the past season, have resulted in completing the survey of 

 the mountainous portion of Colorado, with a belt of Northern New 

 Mexico fifteen miles wide, and a belt in Eastern Utah twenty-five 

 miles wide. 



For the summer's work four field parties were organized, each ac- 

 companied by a topographer and a geologist, and a large amount of 

 geodetic, topographical, and geological work was done, the details 

 of which will be found in the body of the present work. 



Six sheets of the Physical Atlas of Colorado are nearly ready for 

 issue, covering an area of 70,000 square miles. The maps are con- 

 structed on a scale of four miles to the inch, with contour lines at in- 

 tervals of 200 feet. 



The United States Geographical Survey west of the 100th merid- 

 ian, under the command of Lieutenant G. M. "Wheeler, U. S. Corps of 

 Engineers, has been prosecuted energetically, both as to field-work 

 and in the arrangement and reduction of the mass of material ac- 

 cumulated. A detailed account of the results accomplished will be 

 found in the body of this work. 



Under the direction of Professor J. "W. Powell, the exploration of 

 the Rocky Mountain region has been carried on, as in previous years, 

 under the auspices of the Secretary of the Interior. A large amount 

 of triangulation and plane-table work was accomplished by the two 

 topographical j)arties, which were separated from the geological 

 parties, contrary to the custom heretofore. This method of opera- 

 tion gave increased facilities to both branches of the survey. An 

 account of both topographical and geological work is published in 



the body of the work. 



COSTA RICA. 



The results of various surveys have been united by Mr. Friederich- 

 sen. Secretary of the Hamburg Geographical Society, in making an 

 excellent map of the republic of Costa Rica. The map is on a scale 

 of 3oowo 5 ^^ about 8i inches to a degree, and is far superior to any 

 heretofore published of that country. 



BRAZIL. 



In a memorandum prepared to accompany a physical map of 

 Brazil for the United States Centennial Exhibition, Senor Homem 

 de Millo calls attention to the gross errors continually made hereto- 

 fore in the rei3resentation of the mountain and river systems of the 

 empire of Brazil. 



