DENVER & RIO GRANDE WESTERN ROUTE. 131 
The traveler has now seen the lava flow, though he has probably 
not seen the vent or volcano from which it must have come, but if 
he scans closely the hills across the valley he will see that some of 
them are littered with fragments of the same dark rock that com- 
poses the flow and that others consist wholly of that rock. The 
volcano must have been near the top of the first series of hills, as 
shown in Plate LVI, &, but its crater is now obscured by the lava 
that consolidated in its throat. The vent was small, but it has all 
the essential features of a true voleano. The ravine down which 
the fiery flood rolled into the valley, leaving some of the melted 
rock adhering to its sides as it passed, may be seen from the train. 
(See Pl. LVI, 2B.) 
This eruption seems to have been the last expiring gasp of forces 
that long before poured out immense floods of molten material in 
this region. The material erupted at this place was only enough 
to fill the valley to a depth of 50 or 60 feet but not enough to turn 
the river from its course. The lava extends down the valley half a 
mile beyond milepost 341. 
As the train rounds the bend, just below the limit of the lava flow, 
the valley of Colorado River is visible on the north (right), and 
Eagle River unites with this stream a few hundred yards farther 
on, but the junction is not near enough to be seen from the train. 
Colorado River has its source on the east slope of Mount Richthofen, 
in the northern part of Middle Park, and those who went to the 
summit of the mountains (Corona) on the “ Moffat road” could 
look down on this west side into some of the head tributaries of 
this river. After flowing westward across Middle Park the river 
escapes from that natural basin in the mountains by Gore Canyon, 
a rugged gorge which it has cut through the Park Range—the same 
range which the traveler saw on the east (right) at Tennessee Pass. 
Gore Canyon is cut in granite, but below the Park Range the valley 
is much like that of Eagle River, consisting of a succession of nar- 
row canyons with stretches of broad valley between. This alterna- 
tion is repeated many times along the river before it is joined by 
Eagle River at the siding of Dotsero. At the point of junction there 
is visible far to the north a high plateau, which is locally called The 
Flattops or the White River Plateau, from the stream that drains 
its western slope. It has an altitude of 11,000 to 12,000 feet and is 
hoted as the greatest hunting ground of western Colorado. It was 
here that Theodore Roosevelt made one of his famous hunting trips 
while he was President of the United States. The preservation of 
the plateau at this high altitude is largely due to the fact that soon 
after its even surface was formed it was covered from some vent in 
this region with lava, which afterward cooled and consolidated into 
a basalt that has successfully withstood the action of the elements 
