Mower County transcript. [volume] (Lansing, Minn.) 1868-1915, 1888-06-20
GREAT LAVA FLOOD.
How tho Columbia River Makes Its w
Through tho Cascade Range.

How tho Columbia River Makes It's Way
Through tho Cascade Range.
The central and eastern parts of Oregon
are vast bed Of lava, which covers, &C.
cording to Prof. La Contc, between 100000
and 3O0, 600 square miles OF territory. 1t Is
probably tho most extraordinary lava flood
in the world. Commencing in Middle Cali.
fornio as separate streams, in Northern
California it becomes q flood flowing over
and completely raanteling the smaller inc.
qualities, and flowing around tho greater
inequalities Of surface, while in Northern
Oregon and Tacoma it becomes an absolute.
~ universal flood, beneath which the whole
original face of the country, with its hills
end dales, mountains nnd valleys, lies
buried several thousand feet. It covers
the greater portion of Northern California
and Northwestern Nevada, nearly the whole
Of Oregon, Tacoma and Idaho, and runs fol
into Montana on the east and British Colum.
bia on the north. e.
This enormous matter evidently arose
through assures, and flowed until the
streams or masses met, forming an almost
continuous sheet. Tho Cascade range OF
mountains seems to have been g source OF
immense overflow.
Tho area covered by this overflow con not
be less than 100000 square miles, with ar
average thickness OF about z, 600 feet, but
having q thickness in some places Of 8, 7N
feet. Tho statement, which seems ON ex.
traordinary one, lis sustained by the ex'
tcnsive observations OF Prof. LIE Conte
Tho Columbia river cuts through tho Cas-.
cadc range in a gorge hundred miles ir
length, with perpendicular cliffs. The cas-.
cades of tho river arc at the axis of the
range, and the cliffs here are $500 to 3,S0(
feet above the river surface, and arc com.
posed Of lava, tier upon tier, from top tt
bottom. Considering surface erosion, COX
feet is regarded as moderate estimate 70,
tho original thickness of tho lava flood 81
this place.
But the entire thickness Of the lava has
been cut through, and the surface revealed
on which tho food was originally formed
Hero, at the rivers surface, underlying the
mountains Of lava, arc remains of ancient
forests and evidences Of interesting geo
logical changes.
There occurs at the rivers edge, anG
| about fifteen feet upward, layer Of course
conglomcrate; on this, layer which ap
pears to have been dirt-bed, or old grouni
surface. On this surface were found two
silicified stumps, with their roots spread
out, one Of which was two feet in diameter
the roots reaching over On area twenty fee
| in diameter. Trunks Of other trees were
seen. Over this was layer of stratihet
sandstone, with beautiful impressions O.
leaves Of several kinds of forest trees. Up
on this lies about one hundred feet of con
| glomerate, resembling drift, in the bottom
of which were found trunks and branches
Of oaks and conifers. Upon the conglom
crate the lava lies in columnar masses to
height of :, 500 feet. s..-+t.
The geological age Of the wood and lea
bearing stratum is believed to be mlocene
or middle tertiary, and, if SO, tho lava fioot
began to occur during or after the miocene