260 Geology and Botany of Northern Pacific Railroad. 



tinct layers, the products of different overflows from the great 

 volcanic vents north and south of it.. Cape Horn, a bold head- 

 land, shows a vertical face of trap nearly 500 feet in height. 



No one who examines the gorge of the Columbia will fail to 

 be convinced that it has been cut by the river. The general 

 altitude of the mountains, in which there are no other passes 

 lower than about 5,000 feet, as well as the altitude of the lake 

 deposits on the eastern side, indicate that the work of cutting 

 this channel began at a height of not less than 3,000 feet above 

 the sea. At this time the river must have had a fall of at least 

 this number of feet into the valley of the Willamette, and we 

 must picture to ourselves a series of cascades of greater magni- 

 tude and more picturesque than any now known. This water- 

 power was, however, busily engaged in cutting down the barrier; 

 and in process of time this was so completely removed that a 

 navigable canal was opened from the Dalles to the ocean. The 

 western entrance to the gorge is now at tide-level, and the lower 

 part of the river is, like the Hudson, an arm of the sea. It is 

 true that at present the "Cascades of the Columbia" form a se- 

 rious interruption to the navigation of the river, for they are 

 produced by a dam 63 feet high, which fills the channel for three 

 miles. But this dam, as we know, is of recent date, and has 

 been caused by an avalanche from the sides of the gorge. Above 

 it, the river is simply a long lake, and in low water a series of 

 stumps and trunks can be seen coming up from below the water- 

 level, which belonged to trees that could never have grown in 

 the places they occupy, if the barrier of the Cascades had 

 existed. 



Steamboats navigate the Columbia from the Dalles down, with 

 a transfer at the Cascades ; and this is much the better route to 

 take for those who would get a good view of the gorge, with its 

 imposing walls, its hanging forests and its piciur^sque waterfalls 

 which leap 1,000 feet from. the cliffs, — to say nothing of the old 

 Indian burial-grove, and the multitude of silicified tree trunks at 

 the Cascades. The railroad is built along the face of the south- 

 ern cliff, high above the water, and although it gives only a one- 

 sided view of the gorge, is generally chosen by travelers who pre- 

 fer rapid transit to beauty of scenery. 



