A Salt Mountain in the Great Plains,

"said to be [180] miles long, and [45] in width, composed of solid rock salt." OK, it doesn't actually exist, but Thomas Jefferson thought it did; see also here. The rumor may have been started by Zebulon Pike -- not, despite his name, a Star Trek alien (as Sasha has pointed out), but rather the explorer for whom Pikes Peak was named.

But oddly enough, the salt formation under Hutchison, KS is somewhere near that in scale
9.4.2008 5:30pm
Jefferson also hoped to find Mammoth Elephants roaming the Northern Plains. I find it so hard to teach this period in my freshman survey classes, because it is so hard for the students, and me, to imagine America being unknown territory to such an extent.

The kids laugh when I tell them some of the thing TJ thought might be out there. But I try to remind them that the very first dinosaurs were only then being found in England. And TJ and co's knowledge of chemistry would have extended to air, earth, fire, and water.

Science was quite different then. We are able to laugh at their ignorance only because they and their successors did the work so that we could know.

(And, yes, the history of natural history is a passion of mine.)
9.4.2008 5:47pm
Bama 1L:
Don't forget the Welsh Indians!
9.4.2008 6:00pm
a knight (mail) (www):
This is a poorly researched, incomplete, and distorted reference to Thomas Jefferson. The citation is found in a long and detailed report sent to Congress attributed to Thomas Jefferson, in his capacity as President.

The following citation is from:

Annals Of The Congress Of The United States ebates And Proceedings In The Congress Of The United States; With An Appendix, Containing Important State Papers And Public Documents, And All The Laws Of A Public Nature; With A Copious Index. Printed And Published By Gales And Seaton. Eighth Congress - Second Session: November 5, 1804, To March 3, 1805. Pub 1852 (Google Books link). (any transcriptions errors are mine)

November 14, 1803. An Account of Louisiana.

The object of the following pages is to consolidate the information respecting the present state of Louisiana, furnished to the Executive by several individuals among the best informed upon the subject. (p 1498)

[. . .]

The salt works are also pretty numerous: some belong to individuals; others to the public. They already yield an abundant supply for the consumption of the country, and, if properly managed, might become an article of more general exportation. The usual price per bushel is one dollar and a half in cash at the works. The price will be still lower as soon as the manufacture of the salt is assumed by Government, or patronised by men who have large capitals to employ in the business. One extraordinary fact, relative to salt, must not be omitted. There exists, about one thousand miles up the Missouri, and not far from that river, a salt mountain. The existence of such a mountain might well be questioned, were it not for the testimony of several respectable and enterprising traders who have visited it, and who have exhibited several bushels of the salt to the curiosity of the people of St. Louis, where some of it still remains. A specimen of the same sail has been sent to Marietta. This mountain is said to be one hundred and eighty miles long, and forty-five in width, composed of solid rock salt, without any trees, or even shrubs on it. Salt springs are very numerous beneath the surface of this mountain, and they flow through the fissures and cavities of it. Caves of saltpetre are found in Upper Louisiana, though at some distance from the settlements. Four men, on a trading voyage, lately discovered one several hundred miles up the Missouri. They spent five or six weeks in the manufacture of this article, and returned to St. Louis with four hundred weight of it. It proved to be good, and they sold it for a high price. (p 1504)
9.4.2008 6:00pm
Hoosier wrote at 9.4.2008 4:47pm:
And TJ and co's knowledge of chemistry would have extended to air, earth, fire, and water.
Wasn't TJ a good friend of Joseph Priestley, who discovered oxygen ("dephlogisticated air") in the 1770s, thus proving that air was not an element?
9.4.2008 6:07pm
fub--I'll have to check. But if I recall correctly, Priestly left "airs" as elements. Oxygen was one air, in his thinking. No?
9.4.2008 6:16pm
Sorry--I should have clarified "element" in the Medieval sense.
9.4.2008 6:16pm
a knight wrote at 9.4.2008 5:00pm:
[citing November 14, 1803. An Account of Louisiana.]: The price will be still lower as soon as the manufacture of the salt is assumed by Government, or patronised by men who have large capitals to employ in the business.
It is good to see evidence that not all economic delusions sprang from Marx.
9.4.2008 6:18pm
Hoosier wrote at 9.4.2008 5:16pm:
But if I recall correctly, Priestly left "airs" as elements. Oxygen was one air, in his thinking. No?
I'm not expert on history of science, but I think you're substantially correct. That is, Priestly characterized the gases he discovered as various "airs".
9.4.2008 6:25pm
Anderson (mail):
It *was* there, but then there was a huge rainstorm.
9.4.2008 6:58pm
Ex parte McCardle:
What the hell does this have to do with Obama and Sarah Palin?
9.4.2008 7:18pm
tommears (mail):
Useless Star Trek Triva Follows...

I think you or Sasha are conflating Zefram Cochrane (human discover of warp drive) and Captain Christopher Pike (captain of the Enterprise prior to Kirk). I do not believe there was a Zebulon Pike character in any of the Star Trek TV shows.
9.4.2008 7:33pm
Y'all are possibly thinking of Antoine Lavoisier (1743-1794), the first to recognize that air was not one element, i.e. that there was an actual distinction to be made between "gas" and "air," and who named the element oxygen. This is in roughly 1776, and when Jefferson was in France in the 1780s he would probably have become familiar if not with Lavoisier specifically than probably with other great chemists of the day (e.g. Scheele). The late 1700s and early 1800s were generally speaking a time of phenomenal advance in chemistry, much like the early 20th century was in physics.

That is, although I don't know for sure, not having perused that part of Jefferson's history, I would strongly suspect Jefferson's understanding of chemistry was considerably more sophisticated than Plato's four elements.

It's also worth noting that Jefferson had a strong interest in refuting the great Buffon's rather contemptuous assertion about the size of New World fauna. Inasmuch as Jefferson was an enthusiast at practically everything he did, it would probably be easy for him to swallow a few Paul Bunyan tall tales about the American West if it suited his geopolitical longings (e.g. to put a finger in Buffon's aristocratic eye).
9.4.2008 7:51pm
Eugene Volokh (www):
tommears: Sorry I wasn't clear -- my jocular suggestion was that Zebulon Pike sounded like a Star Trek alien (or perhaps a Star Trek character, if you focus more on the last name), not that there was actually an alien with that name in Star Trek.
9.4.2008 8:58pm
Glenn W. Bowen (mail):
"Captain Christopher Pike"

...horribly injured, and confined, apparently, to a rolling steam cabinet.
9.4.2008 9:51pm
tommears (mail):
No Zebulon is definitely more of a Dr. Who or Hitchhikers Guide sort of name. It definitely has a Brit SciFi flair rather than American ;->
9.4.2008 11:02pm

Lavoisier?! Like I can afford cognac!
9.5.2008 12:21pm