48 COOCHETOPA PASS. 
sections of the route explored, as follows: **'The instruments are kept one hour's distance apart, 
and record simultaneous readings at the different points of the route. The barometers being first 
read in camp for comparison, say at 7 o'clock a. m., the party which goes in advance moves for- 
ward at once for one hour. At 8 o'clock the barometers are read for altitudes, and the odome- 
ters for distances, and the necessary bearings by compass are taken. A small flag is then num- 
bered and planted at this point, when the advance party again moves forward, and aj 9 o'clock 
performs like operations; while the rear readings are made in camp at 8 o'clock, and at 9 at 
statien No. 1, and so on at 10, &c." 
By this method of levelling we ascended from our camp east of the summit, 154 feet 4 inches 
per mile for the first mile and sixty-two hundredths ; 215 feet 9 inches per mile for the next 
mile and thirty-nine hundredths; 396 feet 6 inches per mile for the following fifty-eight hun- 
dredths of a mile; and 292 feet on the last twenty-four hundredths of a mile at the summit, 
or nearly 1,200 feet to the mile. Observations taken for the purpose of ascertaining what extent 
of deep cutting could be easily effected, gave a descent of 102 feet in the first 350 feet on the 
eastern slope; and, allowing fifty yards for the length of the summit, an equal distance gave a 
descent on the western slope of 82 feet. But in constructing a railroad, the level of our camps 
and path would be disregarded wherever it could be best effected by ascending the hill-sides along 
the pass, distributing the elevation to be overcome over a longer and more uniform grade. The 
ravine character of the pass is such, however, narrow and direct, (with sides broken by numerous 
lateral ravines,) rising to no considerable height above the stream, that the elevation to be thus 
gained would be thrown entirely upon the last few miles preceding our camp, 3.83 miles below 
the summit, and could not probably exceed 200 feet. If, therefore, this pass be deemed desi- 
rable for a railroad, it will be necessary, after having gained this elevation at this camp, to pass 
the summit with a grade of 124 feet to the mile, which will require a tunnel, including a deep 
approach from the west, of not less than two miles in length, entering the | hill three-fourths of 
a mile below the summit on the east, and a short distance above our camp 1.33 mile west of 
the summit—diminishing the elevation to be overcome by 490 feet. Below this camp the natural 
grade again becomes practicable for a railroad; for a wagon road this pass is already practica- 
ble. In the Sahwatch mountains, to the north of this pass, another pass exists, leading from one 
of the numerous little branches which we passed after leaving the Sahwatch spring, to the head 
of the Coochetopa creek, but it is not favorably represented. Captain Gunnison concludes his 
notes upon this pass by the remark, “that it occupied five hours to cut the road and make the 
passage of this ridge—the men working hard; and Captain Morris deserves great credit for the 
manner of executing the labor and selecting the route." : 
September 3.— We proceeded down the valley of Pass creek in a westerly course, the hills 
on each side being cut by small rills, deep back towards their summits, which will render a 
winding route and much cutting and filling necessary in constructing a railroad, for which the 
southern side of the creek is the most favorable. Four miles from camp we passed a broad val- 
ley extending several miles to the south towards the Sierra San Juan, whose northern slopes are 
still covered with large fields of snow. Opposite this valley that of Pass creek widens consider- 
ably, and we passed easily down it for six miles further to where another valley sweeps off to the 
south, through which a fine creek descends, and, uniting with that of our path, enters a broken 
cafion. The valley from this point extends to the south towards the snowy peaks of the Sierra 
San Juan, near which the Sahwatch creek is said to rise, flowing north and east along the base 
of the mountain to the east of this and the preceding valleys, where its waters approach 
nearer those flowing into the Pacific than at any other point. The Carnero Pass leads from 
that creek - over this ridge, and its summit does not appear more elevated than that of the 
'hetopa; and its western descent much more favorable for a road. Our guide, Leroux, repre- 
sented its approach from the east, however, as more abrupt than that of the Coochetopa Pass, 
and did not think it omes for our wagons to pass through the rocks and timber which 
