48 
ROUTE NEAR THE FORTY-SEVENTH AND FORTY-NINTH PARALLELS. 
changing to 12 feet, 6 feet, &c., &c. But the question should not he considered settled until 
further examinations and an instrumental survey of the Yakima Pass are made. 
The terminus of the road should he on Puget sound, and, from the report of Capt. McClel¬ 
lan, the harbor of Seattle'would appear to be the most favorable on the eastern shore. To 
return to the crossing of the Columbia river near the mouth of Snake river. 
Capt. McClellan states: “ With regard to the Columbia river, I am not prepared to speak 
so much in detail; the last barometer being broken before we reached there on our return, 
and for other good reasons, I passed down by water. Mr. Lander, however, travelled the 
greater part of the distance by land ; and as his examination corroborates the opinion I 
formed at the time, I shall content myself with expressing in general terms the nature of 
that pass.” His conclusion is, that “it is not only practicable, but remarkably favorable;” 
and, in his opinion, it would be desirable that an instrumental survey should be made of the 
Yakima Pass and the Columbia River Pass, should any more railroad explorations be made on 
this line. In conversation Capt. McClellan informed me, that the work on the route along 
the Columbia river, from the Dalles to near Vancouver, 90 miles, would be similar to that 
of the Hudson River railroad along the mountain region. Mr. Lander says, “the high 
floods to which the Columbia river is subject, are serious obstacles to obtaining the best 
location for cheap construction offered by its valley.” From observations made at Fort Van¬ 
couver, from May 8 to July 20, 1854, the rise of the river during the flood was 10 feet above 
spring level, and 11 feet above summer level. 
Governor Stevens says: “The pass of the Columbia river, examined personally by myself 
as well as Captain McClellan and Mr. Lander, is remarkably favorable in its grades, which 
rarely exceed ten feet, in the ease with which debris from the ledges can be worked to form 
the embankments required to guard against freshets, and the great facility with which wood 
and stone, both of good quality, can be transported down the Columbia for purposes of con¬ 
struction. The only serious obstacle is Cape Horn mountain, which, to avoid sharp curvature, 
may require a tunnel seven hundred feet in length. The grades down the Columbia to near 
the mouth of the Cowlitz, and thence to Olympia, Steilacoom, or Seattle, will be small, the 
work light, and abundant materials of all kinds will be found for road-beds and super¬ 
structure.” The ascents and descents are estimated at 300 and 100 feet. On the Columbia 
the line is, for the most part of the way, located in the bottom lands of the river, and will 
rarely be forced from them to the rocky bluffs bordering its intervale. Between Wallah- 
Wallah and the Dalles Mr. Tinkham found it necessary in only two instances to cross the 
rocky spurs jutting out from the river bluffs. 
The bluffy country bordering the Columbia ceases near Cape Horn. From below the Dalles 
the woods commence, and continue to the head of Cowlitz river. 
“The wide and comparatively flat and wooded valley of the Cowlitz connects with plains, 
sometimes of prairie and sometimes of woodland, extending to Puget sound, and which, although 
not fully explored, are sufficiently well known to insure the unusually favorable character of 
the country for the construction of a railway.” 
The total length from the crossing of the Columbia to Seattle is about 390 miles. The 
earth excavation will not probably exceed the heaviest work of the prairies east of the moimt- 
ains, and is estimated not to exceed an average of seven to eight feet. The material for em¬ 
bankment is almost always of a superior character. 
The amount of rock-cutting, with the exception of the portion of the line between the 
Dalles and Cape Horn, will be very small. The rock is generally a basaltic trap. 
In reference to the facilities for construction upon Clark’s fork and on the Columbia, Gov¬ 
ernor Stevens says: “By improvements either in the bed of the river, or in the use of locks at 
several points on the Columbia and Clark’s fork, and by the substitution of rail where such im¬ 
provement is impracticable, it is not doubted that a continuous communication can be established 
from the mouth of the Columbia to the mouth of the Spokane, and probably to Colville, and 
