Talk:Bridge of the Gods (land bridge)

Comment from Bonneville Slide article
(merged 3/08)

The putative "five hundred years ago" and "18th century" (e.g. 1700) dates do not match. Hu 21:20, 26 January 2006 (UTC)
 * Be Bold! T e  k e  02:21, 12 June 2006 (UTC)

I believe this slide was dated at approximately 850 y.b.p. The source was radiocarbon dating of wood fragments from the former stream bed that were buried under the landslide. The wood fragments were uncovered during the excavation for the Second Powerhouse at the Bonneville Dam and during subsurface investigation for the Bonneville Juvenile Fish Bypass structure.--Kern doggie 17:40, 1 November 2006 (UTC)

Comments from this article
Has it been verified geologically? Everything I've seem refers to it as an Indian myth. The size of the Columbia also makes it highly unlikely.
 * "According to the lore of these tribes, long ago a huge landslide of rocks roared into the Columbia River near Cascade Locks and eventually formed a natural stone bridge that spanned the river. The bridge came to be called Tamanawas Bridge, or Bridge of the Gods. In the center of the arch burned the only fire in the world, so of course the site was sacred to Native Americans. They came from north, south, west, and east to get embers for their own fires from the sacred fire." 


 * Yes, the original contributor was on target here. I don't have a citation right now, but I am sure that it has been researched and verified geologically.  I'll insert an appropriate reference when/if I come across it again.  Ipoellet 18:46, 25 March 2007 (UTC)

Proposed merge
The articles Bridge of the Gods (geologic event) and Bonneville Slide deal with overlapping and very closely related topics. Specifically, the Slide article appears to approach the issue as a geophysical event investigated through contemporary scientific methods, while the Bridge article examines the same event through the lens of Native American folklore. Both aspects could be given added dimension by being dealt with in a single article, with text specific to each aspect separated out under distinct headlines.

I recommend "Bridge" to be the final destination article name because: (a) it is the older name for referring to the same historic event; (b) it seems to be the better known name, i.e. I'd heard the Bridge of the Gods name before coming to Wikipedia, but not Bonneville Slide; and (c) it stands in neat complementarity to Bridge of the Gods (modern structure).

See also: Merging and moving pages

-Ipoellet 20:19, 2 April 2007 (UTC)


 * merge: both articles are a bit light on content now and will combine nicely. Having them separate is a light shade of POV actually. :-) —EncMstr 20:31, 2 April 2007 (UTC)
 * merge: same event. Use Bridge of Gods as title. One article can easily cover both the folklore and geologic background. Aboutmovies 18:26, 31 May 2007 (UTC)

Hearing no objections, it appears we have consensus. I'm proceeding with the merger, and expect to be done in the next several days. For intermediate drafts, see User:Ipoellet/Sandbox 3. -Ipoellet 19:55, 31 May 2007 (UTC)


 * Merge per above. Katr67 18:02, 5 June 2007 (UTC)


 * I have a draft of the merged article in progress at User:Ipoellet/Sandbox 3. -Ipoellet 19:25, 9 June 2007 (UTC)


 * I was going to say keep separate until I saw Ipoellet's draft. It could use more geological data, if available, but is otherwise a nice combination. Merge, but if new research makes the Bonneville Slide more prominent than the legend, don't be afraid of a name change. MMetro 02:43, 9 November 2007 (UTC)


 * Missed this before, but I'd say about time, as long as somebody's willing to do the work. Thanks for taking this on Ipoellet!! -Pete 03:01, 9 November 2007 (UTC)
 * My comment is late, but the merge hasn't happened. I'd rather see them separate, and hope someone can provide more geologic detail to the "Bonneville Slide" article (or "Bridge of the Gods (Geologic event)").  The story and geology don't fit that well to my eye. Pete Jacobsen (talk) 02:32, 15 December 2007 (UTC)

Failed proposal?
OK, this proposal has been dead in the water (pun unintended) since April, despite what appears to be a consensus to merge. Anyone mind if I remove the tags and if Ipoellet gets around to finishing the merge project, we can agree to that change without prejudice? Katr67 (talk) 01:56, 12 January 2008 (UTC)

Date of Bonneville Landslide
Pete pointed out on the Columbia River talk page that the dates of the Bonneville landslide given in sources are confusing, with many sources being non-scientific and dates cited from 1200 (or earlier I've found) to 1760, etc. Finetooth gave a good summary of the "current thought" about the landslide date, sourced to pp. 252-53 of In Search of Ancient Oregon. After wading through online sources I think the summary is accurate though perhaps slightly biased toward the earlier date estimates ("Although the fifteenth-century dates seem reliable, some geologists harbor suspicions that this massive slide was more recent..."--sems to suggest that the earlier date is basically correct even if some geologists "harbor suspicions" it isn't...I don't know, the wording makes my POV bias alarm ring a bit). If nothing else I can provide a number of sources and an outline of the history of the study of the landslide:

There were many very early descriptions and theories about the Cascade Rapids, a landslide, natural dam, submerged forest, etc, such as Lewis and Clark, John S. Newberry, Ira A. Williams, and others. There are also the various Native American oral histories. I'm skipping over all these. They are easy enough to find--like in Jim O'Connor's The Evolving Landscape of the Columbia River Gorge, Richard Hill's two essays, A New Look at an Old Landslide, and Great Cascadia Earthquake Penrose Conference - The Oregonian Article.

Estimating the date of the Bonneville Landslide got more serious with dendrochronology (tree ring counting) in the 1930s and radiocarbon dating starting in the late 1950s. The first detailed dendrochronology effort was done by Donald B. Lawrence in the 1930s. He published his results in Oregonian, August 8, 1935 and in "The Submerged Forest of the Columbia River Gorge," Geographical Review 26 (1936). I'm not sure if these two are online but they are summarized by Jim O'Connor in "The Evolving Landscape of the Columbia River Gorge" (linked above). O'Connor's text is a little confusing. He give the impression that Lawrence's first date estimate was "before 1735" but was later revised to "before 1562". In any case Lawrence later had his tree samples tested by radiocarbon dating. This was done in the late 1950s when radiocarbon methods were new and not very good relative to today's methods. The radiocarbon dating results lead Lawrence to conclude the landslide occurred around 1060-1180 (according to Reynolds, Dating the Bonneville Landslide with Lichenometry) or "about 1250" (according to O'Connor, "The Evolving Landscape of the Columbia River Gorge"). Lawrence (and E.G. Lawrence) published the results in: D.B. Lawrence and E.G. Lawrence, "Bridge of the Gods Legend, Its Origin, History and Dating," Mazama 40:13 (December 1958): 40–1.

The next serious estimate was that of Rick Minor, "an archaeologist with Heritage Research Associates in Eugene, for the U.S. Army Corps of Engineers". Minor used radiocarbon dating methods on wood samples obtained in 1978 when excavation for a new powerhouse at Bonneville Dam was being done. Some of the results were over 3,000 years old, but one douglas-fir log tested indicated a date for the landslide of 1060-1180. Minor seems to have simplified this range to 1100 and promoted his results as correlating well with the Lawrences' estimate. Minor published his work in Minor, Rick, 1984, Dating the Bonneville landslide in the Columbia River Gorge: Heritage Research Associates [Eugene, Ore.] Report 31 [under contract to U.S. Army Corps of Engineers], p. 19. Apparently Minor's estimate of 1100 "has often been cited", according to Reynolds, "Dating the Bonneville Landslide with Lichenometry".

The work of Lawrence and Minor together resulted in the estimated date of "about 1100"--apparently the only serious date estimate for a number of years.

In the late 1990s the key log that Minor had tested and based his estimate upon was retested by Patrick Pringle and Robert Schuster. They "were puzzled" by Minor's date of 1100 because the "submerged forest" trees were still visible in the river into the 1930s. Radiocarbon methods had improved and a differing approach to taking samples from the log was used. The results lead Pringle and Schuster to publish as estimated date of 1500-1760. This would have the Bonneville landslide occurring much more recently--"closer to 1700"--than the earlier estimate of "about 1100" or perhaps 1200. All this is summarized in Hill, "A New Look at an Old Landslide".

The date estimate of "about 1700" was strengthened by Nathaniel D. Reynolds, who used lichenometry to estimate the date of the landslide. Reynolds date estimate is 1670-1760. He published his work in Dating the Bonneville Landslide with Lichenometry; Washington Geology December 2001 (v. 29 no. 3/4), pp. 11-16. His work is also described in Hill, "Great Cascadia Earthquake Penrose Conference - The Oregonian Article" (linked above). Personally I found Reynolds's paper quite professional, especially compared to O'Connor. Reynolds describes the history of the study of the Bonneville landslide in some detail. He explains lichenometry in general and his approach in particular. He points out how his "biometric" results corroborate with those of Pringle and Schuster (1998), and "provocatively bracket the 1700 date" of the great Cascadia earthquake but warning that "no causal relationship...can be determined by this research". He also suggests how earlier studies might have resulted in inaccurate date estimates, such as: the landslide site is a "composite, multi-event landform"--there were at least four large landslides there--and this was not realized or well understood until recently. Tree ring counting may have taken samples from different "components of the Cascades landslide complex".

All of this would suggest that a date estimate close to 1700 has recently become better established. But there are a couple of recent counter theories. One is by Jim O'Connor. In "The Evolving Landscape of the Columbia River Gorge" (2004) he bluntly states, "the landslide, now known to have been in about 1450". His support for this theory, as far as I can tell (his writing is a bit confused it seems to me), is described in a footnote: "four recent radiocarbon dates (unpublished results, Jim O'Connor and others, USGS, Portland, Ore.)". This strikes me as a rather poor citation that wouldn't stand up in, say, a Wikipedia FA review. After all, not only are the results unpublished, but is he saying he is with the USGS, or "others" are? And who are these "others"? Also, if I understand his writing correctly, the "others" who have done "more recent" radiocarbon dating used the wood samples originally collected in Lawrence way back in the 1930s. O'Connor's paper doesn't come off all that well for me.

Of course my opinion doesn't matter. O'Connor is published in the Oregon Historical Quarterly and cited in other sources, such as David Wilma, Landslide blocks the Columbia River in about 1450 (2006). But I have to point out that David Wilma's HistoryLink.org essay cites only two sources: O'Connor, "The Evolving Landscape of the Columbia River Gorge" and Richard Hill, "A New Look at an Old Landslide". Given that both of these are easily available online we should be able to disregard Wilma's HistoryLink.org essay. It doesn't say anything that isn't already in the other two sources.

The other recently published paper supporting an earlier date is a little confusing. I found it here: Use of Dendrochronology to Date and Better Understand the Bonneville Landslide, Columbia River Gorge, Washington. It appears to be from another source: Geological Society of America Abstracts with Programs, Vol. 35, No. 6, September 2003, p. 80. But the webpage indicates it was "presented" at the "2003 Seattle Annual Meeting (November 2–5, 2003)". All this leaves me a bit confused. But it is by Patrick T. Pringle and Russ Weaver. Pringle is the guy who retested Minor's wood and got date estimates closer to 1700. However this abstract from 2003 concludes that the landslide was "probably before 1550". They used tree ring counting to get this date. I'm not sure what to make of this source.

In conclusion I think it is safe to say that early date estimates indicated something close to 1200 and more recent ones closer to 1500 or 1700. And that the date is still an unresolved issue without general agreement among those studying it. And also that even if the 1700 estimate is correct there is no direct evidence that the Cascadia earthquake was the cause. The date correlation is "tantilizing" but one should remember that correlation does not equal causation. Ok! Sorry for typos. I wrote too much and must go to bed without proofreading. Pfly (talk) 08:42, 6 September 2009 (UTC)


 * Wow-- that's some astonishingly detailed research, thanks Pfly! I didn't make it to the library (got distracted by a local scandal that brought 18,600 hits in one day to a stub-class article…), but this is a whole lot to work with. Much appreciated!! I'll be back after coffee. -Pete (talk) 16:48, 6 September 2009 (UTC)

Klickitat oral tradition
There are some disputable assertions in this section, based on the linguistic evidence. To wit: "Tyhee Saghalie" is Jargon, not Klickitat. The fact that this term is expressed in Jargon reflects the fact that the concept ("Chief-in-the-Sky", i.e., the Christian God) did not exist in local aboriginal religions before the arrival of Jesuit missionaries, who preached in Jargon. The legend as offered isn't pre-contact, and has likely been bowdlerised in the transmission.

Similarly, "Tanmahawis" is Jargon for magic, spirit, life-force, soul, and related intangibles. It could not have been the name of a bridge, though it might serve for "miracle" in a Jargon sermon. Again, the presence of a Jargon word and implied Christian imagery cast doubt on the historical origins of the tale.

Laodah (talk) 22:23, 14 January 2012 (UTC)

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