DENVER & RIO GRANDE WESTERN ROUTE. 91 
The railroad ascends this canyon for several miles and then climbs 
the mountain slopes on the west, finding a way, after many turns and 
loops, over the range through Marshall Pass, which lies’just beyond 
Ouray Peak (00’ray), as shown in Plate LXIX, B (p. 162). Al 
though the line up the Arkansas Valley above Salida was completed 
as far Leadville in 1880 and the line over Marshall Pass in 1881, the 
latter was regarded as the main line and was the first to be finished 
through to Salt Lake City. 
Near milepost 217 a branch line turns to the left to a large silver- 
lead smelter in which much of the ore of this region is reduced. A 
description of such a plant and of the process of smelting is given 
on pages 252-254. <A little farther on there is an abandoned mill 
on the right of the track, one of the characteristic features of a 
mining country that has seen its best days. The old mine that 
supplied ore to be crushed and concentrated in this mill may be 
seen halfway up the mountain slope on the right. The mill and a 
single house constitute Belleview, which is merely a siding for 
trains. A short distance beyond Belleview the railroad crosses the 
Rainbow Highway, which for some distance beyond this point con- 
tinues on the right of the track. 
From Salida up to the Continental Divide and for some distance 
down on the western slope the shape of the mountains has been 
greatly modified by glaciers.. There are no glaciers in these moun- 
tains now, but long ago, during the great ice age, these ranges, 
particularly their east sides, were covered by great masses of ice 
which flowed down toward or into the valleys at their feet, scouring 
out here and there basins from the solid rock. As most of the strik- 
ing scenery in this region is due to the effect of these bodies of mov-__ 
ing ice they are shown on the accompanying maps as they existed 
at the time of their greatest development. The effect of high winds, 
low temperature, and snow on the vegetation at high altitude is 
also well shown at the summit of the mountains, as exhibited in 
Plate XLV, A, which is a view from the automobile road where it 
crosses the Sawatch Range west of Salida. 
About milepost 220 there are many large boulders, like those at 
Parkdale, on a low terrace near the river. As the railroad ap- 
proaches the river the boulders may be seen at close range and at 
higher levels, until they appear on the terrace above the one on 
which the railroad is built. These boulders increase in size north- 
ward until at a place about a mile from the mouth of Brown Canyon, 
which is apparently the place from which they were swept, there 
are boulders of great size; one on the left of the track measures 
24 by 14 by 10 feet, 
