Pleistocene Boneyard

Lewis—and Clark—at Big Bone Lick

Clark's Find

Tooth of Mastodon americanum, from Big Bone Lick, Kentucky.

Mastodon tooth: a large molar

Jefferson Collection, Department of Vertebrate Zoology
The Academy of Natural Sciences of Philadelphia

This specimen was collected for Thomas Jefferson by William Clark in 1807. It was once part of Jefferson's display at Monticello, and later in the President's House in Washington City.

Lewis had absorbed the basics of contemporary geology and paleontology—that the earth's surface was not the result of global cataclysm; that geological time was surely long; and that the fossils in the geological record possibly represented locally extirpated life forms, which owing to unfavorable living conditions may only have been displaced to—in the white person's terms—the hinterlands.

A little more than a month after he embarked from Pittsburgh, heading down the Ohio toward Louisville and St. Louis, he had his first two opportunities—both probably urged on him by Caspar Wistar and Thomas Jefferson—to personally delve into the new science of paleontology under particularly rich circumstances. One was a visit with Dr. William Goforth, a physician and gentleman-naturalist at Cincinnati. The other was a trip to Big Bone Lick, a natural salt lick and fossil bed more than 15,000 years old, situated in Kentucky less than 20 miles southwest of Cincinnati.

On 3 October 1803 he wrote to Thomas Jefferson that he had been visiting Dr. Goforth, who had recently unearthed some prehistoric bones at Big Bone Lick from an excavation 30 feet square and 11 feet deep. None of this would have been news to the well-connected Jefferson. Goforth had written of his work to Thomas Proctor of Philadelphia, who in turn relayed the information to Charles Willson Peale, and he in turn to Jefferson. Each of them speculated on the nature of the mastodon (they still called it a mammoth), comparing the creature's teeth particularly to those of the Asian elephant. Lewis's letter to Jefferson—one of the longest he ever wrote—was a thoughtful, detailed analytical account of Goforth's specimens of "mammoth" tusks.1 He compared the teeth to some from South Carolina that he recalled having seen in Caspar Wistar's collection, and concluded that all the tusks were from the same mammoth, and that the flattened ones were the result of "sand and gravel passing over them for a great length of time caused by a running stream or agitated water." It doesn't really matter whether Lewis was right or wrong. He was showing Jefferson—and us—that he had taken Caspar Wistar's lessons very seriously. That boded well for at least this scientific aspect of his coming journey into the wilderness called Louisiana territory.

Time Warp

This late Pleistocene boneyard, a warm salt spring, gathering-place, death trap and eons-long tomb for mammals of many descriptions, once situated at the southern margin of the last great ice cap, had been known to Shawnee and Delaware Indians for millennia. Euro-American civilization had known of it only since 1739, when French soldiers stationed nearby sent skeletal curios back to Paris. In the mid-1780s Thomas Jefferson mentioned Big Bone Lick in his landmark Notes on the State of Virginia. He recounted the Delaware legend that explained how it came to be, plus an anecdote that hinted the descendants of those long-dead creatures were still to be found somewhere not too far away.2 Twice, in the early 1780s, Jefferson had asked William's older brother, George Rogers Clark, to collect some fossils for him at Big Bone Lick. That didn't happen, but George already knew enough about the place to tell Jefferson he doubted any of the big bones there belonged to a carnivore. He was partly right, as William helped to prove more than twenty-five years later.3

A large number of the mastodon bones Goforth had discovered were still at Big Bone Lick, Lewis reported to Jefferson, and the doctor had given him permission to take some samples. Sending the keelboat on ahead down the Ohio, he made a side-trip overland to Big Bone Lick, less than 20 miles southwest of Cincinnati near the Ohio River in Kentucky. There, marshy salt-spring deposits—some locals called it "jelly ground"—had entombed some hapless members of a diverse fauna that lived during the last ice age (although no one in 1803 yet knew of the great continental glaciations nor the true age of these fossils).4 Lewis noted that many of the fossils still at the site included a tusk and "other bones," and Lewis expected to obtain permission from the site's owner—a land speculator from Virginia—to collect even more of them.

Lewis had the bones he had collected shipped to Jefferson by way of river boat to New Orleans, then transferred to a packet boat that would carry them up the east coast. Misfortune intervened, and Jefferson never received them. The river boat sank in the Mississippi at Natchez. The few boxes that were saved were thrown ashore and left unattended, later to be rifled by Tennessee militiamen then in Natchez, who discarded the contents. Subsequently, Dr. Goforth himself shipped ten crates of specimens from the famous Kentucky fossil bed to Jefferson, but it was somehow sent to England, where a swindler sold the treasures.5

The first shipment of mineralogical and paleontological specimens gathered by the expedition, which the captains sent back from Fort Mandan in April of 1805, reached Jefferson safely. However, what happened to them thereafter spelled misfortune for history. (See "The Missing Fossils.")

Lewis's observations at the lick stuck with him. On 25 May 1805, Clark and Private William Bratton each shot a bighorn sheep—the first they had seen within rifle range—and Lewis wrote an account of his careful examination of the animals. His memory serving him as reliably as his acute power of observation—gifts he called into service many times during the expedition—he recalled: "I obtained the bones of the upper part of the head of this animal at the big bone lick." Clark confirmed it: "Capt. Lewis obtained the bones of the upper part of the head of this Animal at the big Bone Lick in the State of Kentucky which I Saw and find to be the Same in every respect with those of the Missouri [River] and the Rockey Mountains."6 (It is reasonable to assume that in both instances those bones included the horns, since bighorn sheep do not shed them seasonally.) Neither of the captains ventured to say that the animals they shot that day were living examples of species previously thought to be extinct, nor that they had been pushed westward by advancing civilization. Since then, however, paleontologists have confirmed Lewis and Clark's observations, with the discovery at the Kentucky site of fossil remains of an extinct Pleistocene creature said to resemble the bighorn sheep.

In September of 1807 Clark fulfilled a promise he made to Jefferson to collect some bones from the Lick. By that time the fossils had been picked over so much that it took a ten-man crew several weeks to dig up, under Clark's supervision, some 300 bones and teeth. Not only did that shipment successfully reach Jefferson's hands, but also it was accompanied by Clark's eleven-page description of the collection, which was sufficiently detailed to help naturalists begin to differentiate between the remains of mammoths and those of mastodons.7 Jefferson displayed some of those specimens at Monticello, his Virginia home, others in the President's House (later called the White House) in Washington, D.C. He also sent some to the Muséum d'Histoire Naturelle (Museum of Natural History) in Paris, in response to Buffon's condescending deprecation of American fauna.8 The specimens that remained with Jefferson were eventually given to the American Philosophical Society, and today are among the research collections at the Academy of Natural Sciences of Philadelphia.9

In April of 1808 Clark shipped Jefferson three more crates of fossils left over from Big Bone Lick via New Orleans, but British warships forced the boat ashore at Havana, Cuba, and those treasures were lost forever.10


1. Meriwether Lewis to Thomas Jefferson, 3 October 1803, in Donald Jackson, ed., Letters of the Lewis and Clark Expedition with Related Documents, 1783-1854 University of Illinois Press (Urbana, 1962), 1:126-132.

2. Thomas Jefferson, Notes on the State of Virginia, William Peden, ed., (Chapel Hill: University of North Carolina Press, 1982), 43-44.

3. Landon Y. Jones, William Clark and the Shaping of the West (New York: Hill and Wang, 2004), 48, 160.

4. It is now a Kentucky State Park.

5. Jones, William Clark, 160.

6. Moulton, Journals, 4:194, 197.

7. James A. Bear, Jr., and Lucia C. Stanton, eds., Jefferson's Memorandum Books, Accounts, with Legal Records and Miscellany, 1767-1826, 2 vols. (Princeton: Princeton University Press, 1997), 2:1219, 1223-24. For his efforts, Clark was paid $199.66, and shipping charges were due in Baltimore for $34.30.

8. Jefferson to Bernard Lacépède, July 14, 1808. Jackson, Letters, 2:442. Howard C. Rice, Jr., "Jefferson's Gift of Fossils to the Museum of Natural History in Paris," Proceedings of the American Philosophical Society, vol. 95, no. 6 (December 1951), 597-627.

9. For more on the Thomas Jefferson collection, recently curated under a grant from the Save America's Treasures program, see

10. Jones, William Clark, 163, 350n36.