58 ROUTE NEAR THE FORTY-FIRST AND FORTY-SECOND PARALLELS. 
ries, with grades of 69.5 and 40.3 feet per mile. The summit is a broad terrace at the foot of 
the Uinta mountains, and has an elevation of 8,373 feet. From this point the line descends 
over the undulating country separating the Uinta and Bear River mountains, crosses the head 
of Bear river, and, entering the valley of White Clay creek at its head, follows that stream to 
its junction with Weber river. 
The Wahsatch mountains néw intervene between this rolling country and the Great Salt 
lake, and the passage through them may be effected by following Weber river, or by ascending 
to near the sources of the Timpanogos, and descending that stream—both being affluents, 
directly or indirectly, of the Great Salt lake. The distances are about the same to their common 
point on that lake. 
There are cafions upon both these streams; that of the Timpanogos is ten miles in length, 
and narrow, being from 100 to 300 yards in width. It is direct in its general course, but 
must be bridged at several points to avoid short curves. The sides are of blue limestone, and 
will require rock-blasting at some points. The river, thirty yards wide, descends with a pow- 
erful current, and, when most swollen, is six feet above its ordinary level. 
The upper cafion, on Weber river, is rather a gorge, or defile, eight and a half miles 
long. The mountains rise to a great height above it, and are rocky and precipitous, and 
much broken by ravines. The river is winding, and it will be necessary to cross it frequently. 
The lower cafon, near the borders of the valley of the Great Salt lake, is four miles 
long, direct, with an average width of 175 yards, the stream being thirty yards wide, and 
impinging, frequently, with great force against the base of the mountains, which are sufli- 
ciently retreating to admit of the practicable passage of a railway. 
Entering the valley of Great Salt lake from either this or the Timpanogos cation, there 
is no obstacle to the construction of a railway, passing by the south end of the lake, and 
crossing the Jordan, Tuilla valley, and Spring or Lone-Rock valley, to its west side. 
By the valley of the Timpanogos, the distance from near Fort Bridger to the south end 
of the Great Salt lake, on the western side of the valley of the Jordan, is 182.55 miles—the 
greatest grade required, eighty-four feet to the mile. 
The amount of work required on this section, excepting that along the cafion, will not, 
in the opinion of Lieutenant Beckwith, be great. 
‘From the western shore of Great Salt lake to the valley of Humboldt river the country 
consists alternately of mountains, in more or less isolated ridges, and open, level plains, 
rising gradually from the level of the lake on the east to the base of the Humboldt mount- 
ains on the west—that is, from 4,200 feet to 6,000 feet above the sea.’’ West of the Hum- 
boldt mountains the country is of the same character, the plains declining until, at the west 
shore of Mud lake, usually called the foot of the Sierra Nevada, the elevation is 4,100 feet. 
Here the ground rises again to the plain, table-land or basin of the Sierra Nevada, whose eleva- 
tion is 5,200 feet above the sea. It is covered with irregular spurs, ridges, and isolated peaks, 
rising a few hundred feet, leaving a plain surface in a north and south direction sometimes ten 
miles, sometimes only a few hundred yards, in width. In an east and west direction this 
plain is about forty miles in extent, bounded at either end by mountains, the summits of 
the passes through which are 400 and 500 feet above the plain, and which prevent its drain- 
age into the Great Basin, or into the waters of the Pacific. This plain, or basin of the Sierra 
Nevada, might properly be called a part of the Great Basin, since it is in every respect similar 
to it. 
The mountains in this space of 500 miles, between the Great Salt lake and the foot of 
the Sierra Nevada, have a general north and south course; occasionally cross-spurs close the 
valleys to the north and south, but more frequently this isolation is only apparent. They are 
sharp, rocky, and inaccessible in many parts, but are low and easily passed in others, their 
general elevation varies from 1,500 to 3,000 feet above the valleys, and but few of them 
retain snow upon their highest peaks during the summer. They are liberally supplied with 
