GEOGRAPHY OF NORTH AMERICA. 



By SAMUEL H. SCUDDER, 



Cambridge, Mass. 



The most important explorations of the year 1877 were 

 the government surveys of the unsettled parts of the national 

 domain. The oldest of these, the Geological and Geograph- 

 ical Survey of the Territories, under Dr. Hayden, completed 

 its -field work in Colorado in 1876; so that this new state, 

 although perhaps the most diversified in our Union, enters 

 upon life under the most propitious circumstances, its whole 

 territory better mapped than perhaps any older state. In 

 1877 the survey passed northward into Wyoming and Idaho, 

 taking in a tract of countrv between 107 and 112 W. Ions;., 

 extending from the Pacific Railway northward to the Yellow- 

 stone Park an area of about 30,000 square miles. This field 

 of operations, a preliminary survey of which was made in 

 1872, may be more easily conceived by stating that its south- 

 ern border is equal to the distance from Boston to Philadel- 

 phia or Montreal. A geodetic party carried the primary 

 trian ovulation over this entire region, measuring two base- 

 lines one near Rawlins, the other near Bear Lake locating 

 prominent peaks at intervals of from twenty to thirty miles, 

 building upon them stone monuments for future recognition, 

 and travelling at least five hundred miles. Thirty stations 

 were occupied and eleven more used as primary points, and an 

 average of eight angles were measured at each station occu- 

 pied. At the close of the season, the triangulation was con- 

 nected near Ogden with that of the Fortieth Parallel Survey. 



This region was also divided into three sections, each of 

 which was covered by a distinct party, fully equipped for 

 topographical and geological work: two of these divided be- 

 tween them the southern portion, including all the less di- 

 versified desert region ; while the third took the elevated 

 district in the northwest, in the immediate vicinity of the 

 Yellowstone Park. 



