82 : Geographical Notices. 
Art. X1.—(eographical Notices. No. X. 
direction which is given in most of the popular maps. 
‘The mountains in our territory west of the Mississippi rivet, 
from where they rise above the horizontal strata of recent geo 
logical formations on the east to their disappearance under the 
waters of the Pacific Ocean, form a nearly continuous mass of 
upheaved ridges, with occasional intervening level plateats 
The direction of the central line of this mass between the 3: 
and 49th parallels of north latitude, is about north 20° wes 
The greatest width perpendicular to this direction is along the 
e passing from the vicinity of San Francisco through that af 
the Great Salt Lake to Fort Laramie. This distance is 
1,000 miles, or, if we include the Black Hills of Nebraska, 
1,125 miles. : 
“The great mountain mass, of which that in our territory 
forms but a part, extends with varying breadth nearly on the 
line of a great circle of the globé from Cape Horn north to Bek 
ring Straits, and thence south along the western part of Asia ® 
the island of Sumatra. Its length is about 240 degrees, % 
18,560 miles, being two-thirds of the circumference of the earth 
“The area occupied by and included in this mountain 
the level tertiary and cretaceous strata of the eastern plains i 
give evidence of the existence of vast areas whose exte t mus 
} ; ; in some cases whole 
ridges even, having been swept away or broken into separa? 
ons, ae 
_ “Already enough has been learned to establish the existent 
in these mountains of the equivalents of many of the geo! Feed 
formations; and it is probable, when investigations have a 
carried to the same extent as in the civilized portions of 
earth, that the geologist will find here new and still more 
plex fields for research, : 
“The classification of the separate parts of this mount? 
mass, SO as to present its physical characteristics clearly 
a 
