The Mountains of Western North America. 85 
“Since Frémont’s expedition began, a large portion of the 
area of these mountains in the territory of the United States 
as been examined, and many new attempts have been made to 
systematize the knowledge acquired. The most important the- 
ory advanced is that of parallelism in the ranges, the foundation 
of which I shall briefly indicate. 
“On the map o wis and Clarke the Rocky mountain 
Tanges are represented parallel to each other with a northwest 
trend. That this was their theory is evident, from the fact that 
they indicated the Black Hills about the source of the Shyenne 
as having this same trend, though they never saw them, an 
only knew of their existence from hearsay. 
“The maps of Captain Frémont showed a parallelism and 
general north and south direction of the mountain ranges from 
the Wasatch, east of the Salt Lake, to the Sierra Nevada, in- 
cluding all the numerous intermediate ranges. 
_ “The maps made by Major Emory, near the 32d parallel, and 
in New Mexico, showed again a remarkable parallelism of the 
mountain ridges, those in this latitude having a northwest trend 
Cn. parallel to the Rocky mountains, as shown by Lewis and 
arke, 
“The maps of Lieutenants Abert and Peck, of Lieutenant 
Simpson, of Lieutenant Beckwith, Lieutenant Williamson, and 
Lieutenant Parke, have all shown a local parallelism to exist in 
different parts of the mountains. The systems of ridges have 
og varying from a few degrees north of east to north 45° 
es 
. "The idea has lately begun to prevail that this local parallel. 
ism 1s the characteristic of the great mountain mass throughout 
its whole extent. Whether this idea has been true or not it 
been attended with some practical advantages. Instead of one 
er two main summits for an overland road to pass, it shows us 
that we must expect many. On every route explored across the 
Sontinent, at least four well-defined summits have been discov- 
d, and on some of them many more. Some of these ridges 
fnclose interior hydrographic basins. Others are traversed by 
Tvers, but the passes thus made are generally impracticable, 
and, for the purposes of travel, might almost as well never have 
“In many places, however, the mountain ridges have not 
this local paratisian, of which a few instances will be cited. 
The Uintah mountains, east of the Great Salt Lake, trend nearly 
ast and west; the Wind River mountains about north 45° west; 
d the Humboldt range about north 20° east; these three ranges 
§ comparatively near to each other. 
“Humboldt, in speaking of the Sierra Nevada, says, ‘it soon 
Separates into three ae 
