Bob--

I'm resting on my laurels here in NM but wonder about question 7. I had always heard that the longest natural bridge in the world was in Zion. Did I get tripped up on the difference between "longest" and "biggest'? Or am I wrong about both?

Rick Smith

The answer is the one indicated in the quiz. The NPS describes the bridge thusly: "Rainbow Bridge is the world's largest known natural bridge........ From its base to the top of the arch, it is 290 feet -- nearly the height of the Statue of Liberty -- and spans 275 feet across the river; the top of the arch is 42 feet thick and 33 feet wide." In my mind, largest means biggest, and I think that's reasonable. Otherwise....... take your complaint to the Park Service. :-)

Rick,

Are you thinking perhaps about the Kolob Arch in Zion National Park? It's big, but it is not a natural bridge. To be considered a natural bridge, there must be water flowing underneath. I don't think this is the case with Zion's Kolob Arch.

Owen Hoffman
Oak Ridge, TN 37830

"Must" is a bit too restrictive. That's because "water flowing through it" is a suggested standard definition. Several other definitions are in use and are considered at least technically correct, depending on the context. This much we can say with confidence: All natural bridges are arches, but not all arches should be considered natural bridges.

Hmmm, nice technicality, Owen. While there is water flowing nearby, none flows beneath Kolob.

But beyond the question of whether Kolob is an arch or a bridge, it seems than Rainbow Bridge is almost twice as tall ( 290 feet vs. 104.7 feet) as Kolob, so that alone should make it "larger" when pure mass is considered. Although, it seems that Kolob's thickness has been measured at 75 feet, which is roughly 33 feet thicker than Rainbow Bridge, and the width is 35 feet, or just slightly wider than Rainbow.

More arch trivia can be found at this site.

Biggest or largest?

When I worked at Isle Royale, I remember that we usually called Ryan Island the "largest island in the largest lake on the largest island in the largest lake in the world." Pretty much the same as what Bob Janiskee wrote above. But when a fire broke out on Ryan island, and I had the opportunity to name the fire, what did I name it? Not the "Biggest" fire, but the "Largest" fire, of course.

That fire broke out in the fall (from a lightning strike) and it was still smoldering when we left Isle Royale weeks later to close the park and return to the mainland. During the annual winter wolf-moose study, I flew over Ryan Island, now covered with snow. I could finally declare the fire "out" officially. So I suspect the Largest fire may also be the one that burned, at least according to the park's paperwork, for the LONGEST time.

Bob Krumenaker

According to the Zion National Park staff, Kolob is the largest natural arch in the Western Hemisphere:
http://www.nps.gov/zion/naturescience/arches.htm

And according to the Glen Canyon/Rainbow Bridge staff, Rainbow Bridge is the natural bridge in the world:
http://www.nps.gov/rabr/

My handy Glossary of Geology, fourth edition, by Julia A. Jackson has this to say:
natural arch - a natural bridge resulting from erosion
natural bridge -
(a) any archlike rock formation created by errosive agencies and spanning a ravine or valley
(b) ....the remnant of the roof of an underground cave or tunnel that has collapsed
(c) a sea arch or natural arch

Now, the Natural Arch and Bridge Society tries to distinguish a natural bridge as being either a water-formed natural arch or as an arch that has either been used as a bridge or at least simlpy looks like a bridge. Wikipedia also cites the Dictionary of Geologic Terms which says that a natural bridge is a "natural arch that spans a valley of erosion."

Bottom Line: While some people distinguish natural bridge and natural arch, the distinction is neither well-defined nor broadly accepted, and the National Park Service seems happy to claim the "largest" title for both Rainbow Bridge and Kolob Arch...

This is an interesting discussion. With some quarter of a million words to choose from -- more than any other language that is or ever was -- the English language sure is a lot of fun. If you think that sorting out the difference between largest and biggest can be confusing, try sorting out coterminous, conterminous, and contiguous, all of which mean exactly the same thing and can be reasonably well included in the meaning of "continuous." Being a geography professor, I had to deal with the concept on an almost daily basis. I always used "coterminous states" in my lectures and articles. A geography professor colleague invariably used "conterminous states" in his lectures and articles. When we engaged each other in discussion and needed to refer to what most people call the Lower 48, we used the term "contiguous states" and never said coterminous or conterminous. True story.

Bob (Krumenaker), have you read Nevada Barr's two books set at ISRO? If so, are you interested in writing or collaborating on a review of Winter Study for Traveler? I'd really love to get an insider's view.