40 KEPORT OF THE SECRETARY. 



sides, from 800 to 1,000 feet above the bottom, in almost inaccessible 

 positions. From all the information that conld be obtained from the 

 present race of Indians, these dwellings were inhabited at least eight 

 centuries ago by a race of sun-worshippers, which were driven south- 

 ward, step by step, by a persistent foe from the north. 



The sixth division, under Mr. J. T. Gardner, continued the primary tri- 

 angulation over the mountainous region of the southwest, extending 

 into Utah, and connecting with some of Professor Powell's stations. 



The seventh division was under the immediate direction of Professor 

 Haydeu, and made special studies of those portions of Colorado that 

 presented rather complicated problems in geology. A careful survey 

 was made of the Elk Mountains, of the Morainal deposits in the valley 

 of the Upper Arkansas, and the coal-beds along the east base of the Col- 

 orado range of mountains from CaSon City to Cheyenne. The season's 

 labors were in every respect successful, and a large amount of topo- 

 graphical, geological, and natural-history material was secured for the 

 eighth annual report to the Secretary of the Interior. 



The publications of the survey during 1874 were the Bulletin Ko. 1 

 and iSTo. 2, and second series, Nos. 1, 2, 3 ; miscellaneous publications. 

 Nos. 3, 4, 5, Gj Cretaceous Flora, by Leo Lesquereux, 7th Annual Eeporl, 

 (Colorado.) 



Surrey under Professor Powell. 



This was the continuation of the geological and geographical explora- 

 tion of the basin of the Colorado of the West in Utah, prosecuted for sev- 

 eral years previous. For this work two parties were organized, one under 

 the charge of Prof. A. H. Thompson, and the other under the immediate 

 direction of Professor Powell himself. Each party had a number of 

 assistants, and to the latter was added a photographer. Thetirst party 

 ■was enjployed in carrying forward the work in Central Utah, and tlie 

 second party in Northeastern Utah. 



The valley of the Sevier, near the town of Gunnison, was selected as 

 the proper position for the base-line from which a series of triangles 

 could be extended to the north, east, and south, and connected uith 

 those which had been established in former years. 



For hypsometric determinations Green Kiver City on the Union Pacific 

 Eailroad, Salt Lake City, Gunnison, and Pangwitch were selected, fiom 

 their connection with railway surveys, as known points of reference for 

 altitudes to be ascertained by the barometer. 



The geographical determination of latitude and longitude rests pri- 

 marily on the base-line, the terminations of which were established by 

 astronomical observations. For latitude the zenith-telescope was em- 

 ployed, and for longitude telegraphic methods were adopted. 



The material was collected for maijping and exhibiting the resources 

 of a section of country heretofore but little known, embracing many 

 ranges of mountains and i^lateaus, with valleys drained by streams 



