Geology Reference
In-Depth Information
Pathways of separate Columbia River Basalt flows
through the Columbia gorge (after Anderson and
Vogt, 1987)
Beacon Rock
On the north bank of the Columbia upriver
High Cascade Mountains
from Multnomah Falls, Beacon Rock served as a signal
The snow covered Oregon High Cascade
to travellers that the last of the river rapids was behind
mountains offer a variety of spectacular scenery includ-
them and the Pacific Ocean lay ahead. The vertical 850
ing glaciers, snow fields, thick forested slopes, cold
foot high Beacon Rock is part of a north-south extend-
streams and lakes, and waterfalls. The crest of the
ing dike of Cascade andesitic basalt. The resistant dike
range averages a little more than 5,000 feet in altitude,
intruded the surrounding Eagle Creek Formation,
but well-known peaks rise considerably higher. The
which was eventually eroded away leaving the pillar.
High Cascades, part of a chain of volcanic peaks
