80 Explorations in Colorado. [ February, 
The party saw no lakes of more than four hundred yards in di- 
ameter and only two or three of those. The country is nearly 
all inhabitable both winter and summer, and considerable portions 
of it are valuable, and though three quarters of it is within the 
Ute Indian Reservation, the advantage of a more accurate knowl- 
edge of its character can readily be seen. 
While working in the low broken country of Southwestern 
Colorado last year, Mr. Chittenden made use of a light portable 
plane table and found it of great value. It appeared at that time 
that its value was greatest in that class of country, and that in a 
low rolling district with few prominent points, or in a high- 
mountain country, it would probably be of little or no use. 
Altitudes were determined by the mercurial barometer with a 
base at the White River Indian agency and checked by a con- 
tinuous system of vertical angles. The altitude of the agency 
has been determined by a series of barometric observations ex- 
tending over two years and a half and referred to railroad levels, 
and can probably be depended on to within a few feet. The al- 
titude of the agency being about sixty-five hundred feet, and the 
altitudes in the district ranging from five thousand to eight thou- 
sand feet, makes its location the best possible in height for a ba- 
rometric survey of the region. 
It is the intention of the survey during the coming year to 
publish some tabulated results of the barometric work in Colo- 
rado, showing the system and its accuracy and reliability. This 
may be of use in future work, since the topography of the whole 
West must greatly depend on barometric determinations of alti- 
tude, while Colorado has furnished almost every possible phase 
of western topography. 
The longest dimension of the work lying east and west and 
the White and Grand rivers running in approximately parallel 
courses, the district stretched from the White River up over the 
divide between the Grand and White and embraced the heads 
of the lateral drainage of the former river. 
The general topography is a gentle rise from the White River 
towards the south, and a sudden breaking off when the divide is 
reached into rugged and often impassable cliffs known on the 
maps as the Roan or Book Mountains. The gentle plateau 
slope of the White River side is cut by almost numberless and 
often deep cañons, and in many cases the surface of the country 
has been eroded, leaving broken and picturesque forms, the lower 
benches generally covered with cedars and piñons, and the upper 
rich in grass. 
