F. GEOGRAPHY. 267 



for dissenting views. It is highly probable that the results 

 obtained during the past season will admit of a definite de- 

 cision with regard thereto. They will at least be entitled to 

 more consideration than those of explorers who have merely 

 traveled over a limited area, as so large a continuous dis- 

 trict containing: the formation has been examined. It is not 

 possible at present to state positively what these results will 

 be, but from the observations taken in the field it can be de- 

 duced that the age of the lignitic group near Trinidad is 

 not cretaceous. A full discussion of this important subject 

 will be found in the report for 1875. 



Upon the completion of the examination of the just-men- 

 tioned group, the work of the season was connected to the 

 north and northeast with that of 1874, and therewith finished. 

 On October 12th the party returned to Denver, having fully 

 accomplished the purpose for wdiich it was sent out. Im- 

 portant and useful information has been obtained regarding 

 the mineral and agricultural resources of the district, and 

 data have been obtained for the preparation of a topograph- 

 ical and geological map of the area surveyed. 



The southwestern division was conducted by W. II. Holmes 

 as geologist, with G. P. Chittenden as chief topographer, and 

 T. S. Brandegee as assistant topographer. Mr. Brandegee 

 acted as botanist also. 



The area assigned to this division is bounded on the east 

 by the work done by Mr. Wilson in 1874, or a line about on 

 the meridian of 108 W. long., on the south by the parallel 

 of 36 45', on the west by meridian 109 30', and on the north 

 by 37 30' N. lat. These boundaries included an area of 

 about six thousand five hundred square miles. An area of 

 about five hundred square miles was surveyed on the east- 

 ern base of the mountains on the outward march. Here Mr. 

 Chittenden made about twelve stations, connecting with the 

 former work, and completing the sheets to the proposed east- 

 ern line of the survey. 



The easternmost line of the district assigned to this division 

 was over four hundred miles from Denver. The party ar- 

 rived there on the 30th of June, and commenced work im- 

 mediately. 



The work was generally done by means of the plane table, 

 and reinforced by both vertical and drainage sketches from 



