Lewis and Clark's Columbia River
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Lewis & Clark's Columbia River - "200 Years Later"
"Greenleaf Peak, Greenleaf Basin, and Red Bluffs, Washington"
Includes ... Greenleaf Peak ... Greenleaf Basin ... Greenleaf Basin ... Table Mountain ... Table Mountain Landslide ...
Image, 2004, Bradford Island
Click image to enlarge
Greenleaf Peak and Bradford Island. Bradford Island is one of three islands crossed by the Bonneville Dam. Greenleaf Peak is in the background. Image taken October 27, 2004.

Greenleaf Peak, Greenleaf Basin, and Red Bluffs ...
Greenleaf Peak, Greenleaf Basin, and the Red Bluffs are located on the Washington side of the Columbia River, about River Mile (RM) 149. These geographic features are just upstream of Table Mountain and lie directly across from Cascade Locks, Oregon. Good views can be had from Cascade Locks.

Bonneville Landslide ...
The Table Mountain cliffs were created by the Bonneville Landslide, one of the greatest landslides along the Columbia River. Earlier slides created the Red Bluffs and the large scars on Greenleaf Peak. The Bonneville Landslide diverted the river channel a mile and created the legend of the Bridge of the Gods.

"The big cliff of rock visible at Table Mountain, capped by a thick sequence of lava flows of the Miocene age Columbia River Basalt, is the headscarp or source area of the Bonneville landslide, whose debris trail extends to the southeast toward the Columbia River. The impressive cliffs east of Table Mountain that include Red Bluffs, above Skamania Lodge and the Columbia Gorge Interpretive Center, are the headscarp of what is likely an older, although still-active, slowly moving landslide complex. ..."

Source:    Pringle, P., 2009, "The Bonneville Slide", IN: Columbia Gorge Interpretive Center Museum, "Explorations", downloaded April 2014.


Columbia River Basalt Group ...
"Flood basalts of the Miocene Columbia River Basalt Gorup (CRBG) are among the most volumninous and far-traveled lava flows on earth. About 10% of the basalt flows that erupted on the Columbia Plateau between 17 and 12 Ma were voluminous enough to pass through the Cascade arc via a wide ancestral Columbia River valley, and some of them eventually reached the Pacific Ocean. Some of the larger flows invaded the marine strata, forming mega-invasive flows on the continental shelf and slope. ...

The basic geologic framework of the Columbia River Gorge has been known for over a century. In the western gorge, the package of Columbia River Basalt Group (CRBG) flood-basalt flows unconformably overlies volcanogenic rocks of ancestral Cascade volcanic arc. Vigorous and widespread volcanism characterized the arc from its inception 40 Ma until ca. 18 Ma, when activity greatly declines. The arc must have been relatively quiescent during emplacement of the most voluminous CRBG flows, because interflow volcanic sediments are sparse. The larger flows passed through a 50-km-wide ancestral Columbia River valley on their way to the ocean. Owing to late Cenozoic uplift of the Cascade Range and resultant incision by the Columbia River, CRBG flows are now spectacularly exposed in the cliffs and waterfalls of the Columbia River Gorge. The modern gorge roughly follows the northern margin of the broad Miocene valley. Grande Ronde flows clearly abut the northern paleovalley wall formed by early Miocene volcaniclastic rocks of the 19 Ma Eagle Creek Formation. ...

The slight southward dip of the Columbia River Basalt Group (CRBG) section and the underlying Eagle Creek Formation gives the western gorge an asymmetric physiographic cross section. In Washington, failure of weakly lithified Eagle Creek strata that dip toward the river under the load of superincumbent basalt has produced huge landslide complexes composed largely of CRBG debris. In Oregon, where strata dip away from the river, undercutting of the Eagle Creek Formation instead creates towering cliffs. As a result, the CRBG section south of the river consists of continuous cliffs, whereas to the north the CRBG forms scattered peaks (Greenleaf Peak, Table Mountain, Hamilton Mountain, and Archer Mountain) separated by low-lying terrain underlain by the Eagle Creek Formation or landslide debris. Each of these peaks is actually the southern end of a N-S ridge of CRBG, marking sites where basalt flows backfilled south-flowing tributaries of ancestral Columbia River."

Source:    Wells, R.E., Niem, A.R., Evarts, R.C., and Hagstrum, J.T., 2010, "The Columbia River Basalt Group -- From the gorge to the sea", IN: Geologic Society of America Field Guild 15, 2009.


Views ...

Image, 2011, Table Mountain, Greenleaf Basin, Greenleaf Peak, Washington, click to enlarge
Click image to enlarge
Table Mountain, Greenleaf Basin, Red Bluffs, and Greenleaf Peak, Washington, as seen from Cascade Locks Marina, Cascade Locks, Oregon. Red Bluffs is the cliff face left of Greenleaf Peak. Image taken May 20, 2011.
Image, 2005, Greenleaf Peak, Washington, click to enlarge
Click image to enlarge
Greenleaf Peak, Washington, as seen from Cascade Locks, Oregon. Image taken June 19, 2005.
Image, 2006, Greenleaf Peak, Washington, from Cascade Locks, Oregon, click to enlarge
Click image to enlarge
Columbia River, Greenleaf Peak, Washington, and Paddleboat, as seen from Cascade Locks, Oregon. Image taken October 21, 2006.

From the Journals of Lewis and Clark ...

Clark, October 30, 1805 ...
A cool morning, a moderate rain all the last night, after eating a partial brackfast of venison we Set out [from their camp near Drano Lake and the Little White Salmon River]     passed Several places where the rocks projected into the river & have the appearance of haveing Seperated from the mountains and fallen promiscuisly into the river, Small nitches are formed in the banks below those projecting rocks which is comon in this part of the river, Saw 4 Cascades caused by Small Streams falling from the mountains on the Lard. Side,

[The possiblities in a two-mile area are - upstream to downstream - Starvation Creek and Falls, the seasonal Cabin Creek and Falls, Warren Creek and Falls, Wonder Creek and Lancaster Falls, Lindsey Creek and Falls, and Summit Creek and Falls.]

a remarkable circumstance in this part of the river is, the Stumps of pine trees [Submerged Forest]

[The Submerged Forest existed along the reach from above Dog Mountain/Viento Creek on the upstream edge and Wind Mountain/Shellrock Mountain on the downstream edge.]

are in maney places are at Some distance in the river, and gives every appearance of the rivers being damed up below from Some cause which I am not at this time acquainted with [Bonneville Landslide],     the Current of the river is also verry jentle not exceeding 1 1/2 mile pr. hour and about 3/4 of a mile in width. Some rain, we landed above the mouth of a Small river on the Stard. Side [Wind River] and Dined ...   :  here the river widens to about one mile large Sand bar in the middle, a Great [rock] both in and out of the water, large <round> Stones, or rocks are also permiscuisly Scattered about in the river, ...     this day we Saw Some fiew of the large Buzzard    Capt. Lewis Shot at one, those Buzzards are much larger than any other of ther Spece or the largest Eagle white under part of their wings &c. [California Condor] ...     The bottoms above the mouth of this little river [Wind River] <which we Call> is rich covered with grass & firn & is about 3/4 of a mile wide rich and rises gradually, below the river (which is 60 yards wide above its mouth) the Countery rises with Steep assent. we call this little river <fr Ash> New Timbered river from a Speces of Ash <that wood> which grows on its banks of a verry large and different from any we had before Seen, and a timber resembling the beech in bark <& groth> but different in its leaf which is Smaller and the tree smaller. passed maney large rocks in the river and a large creek on the Stard. Side in the mouth of which is an Island [Rock Creek near Stevenson, Washington], passed on the right of 3 Islands <on> near the Stard. Side, and landed on an Island close under the Stard. Side at the head of the great Shute [head of the Cascades Rapids], and a little below a village of 8 large houses on a Deep bend on the Stard. Side, and opposit 2 Small Islands imediately in the head of the Shute, which Islands are covered with Pine, maney large rocks also, in the head of the Shute. Ponds back of the houses, and Countrey low for a Short distance. The day proved Cloudy dark and disagreeable with Some rain all day which kept us wet. The Countary a high mountain on each Side thickly Covered with timber, Such as Spruc, Pine, Cedar, Oake Cotton &c. &c.     I took two men and walked down three miles to examine the Shute and river below proceeded along an old Indian path, passd. an old village at 1 mile [vicinity of Ice House Lake] ...     I found by examonation that we must make a portage of the greater perpotion of our Stores 2 1/2 miles, and the Canoes we Could haul over the rocks, I returned at Dark ...     a wet disagreeable evening, the only wood we could get to burn on this little Island on which we have encamped [near Ashes Lake, the island is now under the waters of the Bonneville Reservoir. Ashes Lake was near the head of the Cascade Rapids. Across from Ashes Lake is Cascade Locks, Oregon.] is the newly discovered Ash, which makes a tolerable fire. we made fifteen miles to daye

Columbia River GorgeReturn to




*River Miles [RM] are approximate, in statute miles, and were determined from USGS topo maps, obtained from NOAA nautical charts, or obtained from the U.S. Army Corps of Engineers website, 2003

  • Pringle, P., 2009, "The Bonneville Slide", IN: Columbia Gorge Interpretive Center Museum, "Explorations", downloaded April 2014;
  • Wells, R.E., Niem, A.R., Evarts, R.C., and Hagstrum, J.T., 2010, "The Columbia River Basalt Group -- From the gorge to the sea", IN: Geologic Society of America Field Guild 15, 2009;

All Lewis and Clark quotations from Gary Moulton editions of the Lewis and Clark Journals, University of Nebraska Press, all attempts have been made to type the quotations exactly as in the Moulton editions, however typing errors introduced by this web author cannot be ruled out; location interpretation from variety of sources, including this website author.
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September 2008