F. GEOGEAPHY. 253 



Colorado ; and Santa Fe, New Mexico. The Salt Lake City 

 party Avas in charge of Lieutenant R. L. Hoxie, of the Engi- 

 neers, and took the field about the 20th of May. The Colo- 

 rado party was under the command of Lieutenant William 

 L. Marshall, of the Engineers, and was occupied in ascertain- 

 ing the general profile of the continental divide, from the 

 latitude of Denver, Colorado, to that of Fort Wingate, New 

 Mexico, and extending laterally, so as to embrace a rectangu- 

 lar area limited on the east by the meridian of 105 30', and 

 on the west by that of 107; on the north by the latitude 

 of Denver, and on the south by the southern boundary of 

 Colorado. 



The Santa Fe division, which was under the immediate 

 command of Lieutenant Wheeler himself, was massed at that 

 place about the 10th of June, for the purpose of connecting 

 the survey with areas previously explored in Northern and 

 Eastern Arizona in 1871, and carrying it eastward as far as 

 the Rio Grande, in order to complete the atlas sheets of the 

 proposed great topographical atlas of the Western territory. 

 By this branch of the expedition a belt of triangulation was 

 carried on to the western boundary of New Mexico, which 

 was completed on the 1st of August; thence, to the south- 

 ward, three parties were started in nearly parallel lines to the 

 southern limit. A sub-topographical party was detailed from 

 this part of the survey about August 1st, connecting north 

 and eastward, with a view of discovering a route connect- 

 ing the head of the San Luis valley, Colorado, with Fort 

 Wingate, New Mexico, or some point to be determined in 

 that vicinitv, from which Northern and Eastern Arizona 

 might be reached by shorter routes. 



In addition to the officers of the army already mentioned 

 in connection with this survey, are First Lieutenant Samuel E. 

 Tillman ; Second Lieutenant Andrew H. Russell, Third Cav- 

 alry ; and Second Lieutenant L. H.Walker, Fifteenth Lifantry. 



The astronomers have already been mentioned. 



The topographei*s are, Louis Nell, chief of triangulation ; 

 B. J. Ainsworth, sub-assistant ; Gilbert Thompson and John 

 J. Young, chief topographers ; E. J. Sommer and Max Schmidt, 

 assistant topographers. 



The meteorological observers are T. O. Brown, William 

 Summers, M. M. Magnet, and C. D. Gedney. 



