The Mineral Specimens

In the late afternoon of 31 May 1805, after another long and arduous day of struggling against the unrelenting current of the Missouri River, Meriwether Lewis, William Clark, and the rest of the Corps of Discovery made camp at Stonewall (now Eagle) Creek in present-day Montana. The laborious work of hauling the canoes and pirogues upstream may have been achingly monotonous and familiar to the explorers, but the route they traveled this day had been a singular revelation. They were passing through a series of remarkable freestanding stone walls and brilliantly white sandstone cliffs, the inspiration for Lewis’s famed journal passage about “seens of visionary inchantment” and “most romantic appearance” describing the White Cliffs region of the Missouri.^[2]Gary E. Moulton, ed., The Journals of the Lewis and Clark Expedition, 13 volumes (Lincoln: University of Nebraska Press, 1983–2001), Vol. 4, 225–226. All quotations or references to journal … Continue reading Yet the captains’ work on this memorable day was not over by any means.

Intrigued by the extraordinary freestanding stone walls that rose on each side of the river, Lewis and Clark summoned the energy to have a closer look at these unique geological features, and not just because they desired to include more detail in their journals. Lewis and Clark were acutely aware that observations of the “mineral productions of every kind” were an essential part of the scientific mission that Thomas Jefferson had outlined for them two years before, but the captains had another objective in mind in the waning light of this late afternoon. As Clark wrote, “both Capt Lewis and My self walked on Shore this evening and examined those walls minutely and preserved a Specimine of the Stone.”^[3]Ibid., 232.

Although not nearly as celebrated as their botanical and zoological work, Lewis and Clark collected a multitude of mineralogical specimens throughout the expedition. There are numerous places in the journals where it’s obvious the captains are collecting rock and mineral specimens. The best known incident took place on 22 August 1804, when Lewis, attempting to assay a specimen, was overcome by what Clark assumed were fumes of arsenic or cobalt.^[4]Ibid., Vol. 2, 500–501. Clark describes this incident in both his field notebook and journal. In the first he says that Lewis “was near being Poisened by the Smell in pounding this Substance … Continue reading

Lewis’s incapacitation may have dampened the captains’ zeal for conducting such experiments, but it did nothing to deter them from continuing their collecting activities. Perhaps realizing their own limitations in the proper identification of rocks and minerals—still a very inexact science in the early 1800s—Lewis and Clark made the wise choice of dealing with mineralogy in the same way they did botany and zoology, by diligently collecting representative samples for shipment back East, where experts could make the proper descriptions and chemical analyses.

Lewis and Clark appear to have assembled at least three separate collections of rock, mineral, and fossil specimens during the expedition, not counting the special shipment of mammoth bones and teeth recovered from Big Bone Lick, Kentucky, that Lewis sent to Thomas Jefferson in the fall of 1803.

The following discussion seeks to unravel the complicated collection history and ultimate fate of the captains’ mineral specimens. It addresses when each shipment of specimens arrived in the East, determining who received and described them, evaluating the accuracy of these descriptions, hypothesizing how the rocks and minerals fell into the hands of a private collector before transfer to the Academy of Natural Sciences (A.N.S.) in Philadelphia, reviewing which specimens survive to the present day, and assessing whether the captains’ mineralogical collection played a role in influencing scientific thought and the advancement of geology and mineralogy in the early nineteenth century.

In early January 1804, when the expedition was at Camp River Dubois, near St. Louis, Meriwether Lewis circulated a survey among the leading merchants and citizens of St. Louis inquiring about population, trade, agriculture, natural history, and other matters relating to “Upper Louisiana,” the territory recently acquired from France by the United States. A number of questions deal with mineralogy. They ask, “What are your mines and minerals? Have you lead, iron, copper, pewter, gypsum, salts, salines, or other mineral waters, nitre, stonecoal, marble, limestone, or any other mineral substance? Where are they situated, and in what quantities found? . . . . Which of those mines or salt springs are worked? and what quantity of metal or salt is annually produced?”^[5]Donald Jackson, ed., Letters of the Lewis and Clark Expedition, with Related Documents: 1783–1854, 2 volumes (Urbana: University of Illinois Press, 1978), Vol. 1, 162.

These inquiries yielded at least 15 mineral specimens, which Lewis forwarded to Jefferson on 18 May 1804, two days before leaving St. Louis to meet Clark and the expedition at St. Charles, Missouri. The specimens were donated by Pierre Chouteau, his half brother Auguste Chouteau, and Nicholas Boilvin, a French-Canadian trader and Indian subagent. The collection comprised a limited selection of minerals of concern to Jefferson; among these were nine samples of lead ore from the “Mine of Berton” (Mine à Burton, located some 60 miles southwest of St. Louis); lead ore from the bed of the Osage River; a salt concretion from a saline of the Osage Nation; and silver ore, lead ore, and a rock crystal from Mexico.^[6]Ibid., 192–193.

Jefferson received these specimens in Washington, D.C., and forwarded them to naturalist and museum keeper Charles Willson Peale, in Philadelphia.^[7]Dated May 5, 1805, Jefferson’s letter to Peale proves that the shipment arrived safely in Washington, D.C. Peale subsequently recorded all these specimens except the salt concretion in his … Continue reading Lewis’s efforts in procuring them confirms that documenting and collecting examples of the “mineral productions of every kind” from the Louisiana Territory was not simply an afterthought in Jefferson’s Instructions.

It’s possible that Lewis began his collecting of mineral specimens while still in the East, for at least one of the specimens sent back from Fort Mandan appears to date from 22 November 1803.^[8]In his journal entry for 22 November 1803, Lewis concisely describes encountering “several pieces of wood that had been petrefyed” (Moulton, Vol. 2, 103), while Fort Mandan mineralogical … Continue reading Lewis also did some sporadic collecting in late May 1804, during the early phase of the journey up the Missouri, in the vicinity of the Femme Osage and Gasconade rivers, but it doesn’t appear he truly engaged in serious mineral collecting until he received a specimen of “granulated Spontaneous Salt”^[9]Fort Mandan mineralogical specimen No. 14. from the Otoes, perhaps during a council with the tribe held on 3 August 1804.

This gift from the Otoes may have reminded Lewis of his obligation to assemble a collection of representative mineral specimens. Whatever triggered the subsequent activity, the next six weeks would be the most productive collecting period for specimens he would later send back from Fort Mandan. On one day alone—22 August 1804— he collected at least nine mineral specimens, followed the next day by at least six more.^[10]It appears that Clark also collected a specimen of the mineral(s) that Lewis had experimented with on 22 August 1804, and subsequently sent it to his brother Jonathan from Fort Mandan. In his letter … Continue reading

There was another flurry of activity between 28 August and 1 September, when seven additional specimens were collected. Lewis appears to have skewed the collection to attractively interesting objects; there may have been at least 12 different specimens of pyrite, a.k.a. “fool’s gold,” along with other minerals such as salts, alum, and weathered limestone sediments whose chemical composition proved too difficult to identify conclusively in the field.

Overall, Lewis attempted to ensure that the collection was representative of the geology encountered along the lower Missouri valley by including samples of salt, “petrefactions,” “carbonated wood,” a fossil fish jaw and fossil shells, flint, sand, clay, “slate,” chalk, sandstone, pebbles, “pummice,” “lava,” and lead ore.

Fort Mandan Shipment

Lewis assembled a collection of at least 67 mineral specimens from late 1803 through early 1805 and sent them back downriver with Corporal Richard Warfington and the expedition’s barge (called the ‘boat’ or ‘barge’ but never the ‘keelboat’) in April 1805.^[11]Jackson, Vol. 1, 235. Included in the shipment were two of the Chouteau-donated specimens (Fort Mandan mineralogical specimen Nos. 27 and 29, from Mine à Burton), which Lewis had received prior to departing Camp River Dubois nearly a year before. Why Lewis included them is uncertain, since he had already provided Jefferson with equivalent specimens in the 18 May 1804, shipment of donated specimens.

A number of letters, particularly between Jefferson and Peale, document the Fort Mandan shipment’s progress and serve as evidence that the specimens reached Philadelphia.^[12]Ibid., 260 (Jefferson to Charles Willson Peale, 6 October 1805), 263 (Jefferson to Peale, 9 October 1805), and 264 (Jefferson to Peale, 21 October 1805). The minerals contained in this shipment are … Continue reading On 15 November 1805, the American Philosophical Society (A.P.S.) received:

A Box of plants, earths and minerals, from Captain Meriwether Lewis, per Jefferson, who wishes . . . Vaughan and Seybert to examine the earths and minerals.^[13]American Philosophical Society, Early Proceedings of the American Philosophical Society . . . Manuscript Minutes of its Meetings from 1744 to 1838 (Philadelphia, 1844), 379.

The above statement refers to John Vaughan, secretary and librarian of the A.P.S., and Adam Seybert, a physician, gentleman scientist, and Philadelphia’s leading mineralogy expert, who subsequently played a major role in the fate of the Lewis and Clark mineral specimens.^[14]Jefferson was aware of Seybert’s singular expertise because they both served on the Historical and Literary Committee that issued a circular letter in 1798 encouraging the scientific community … Continue reading The following day, Vaughn copied specimen descriptive notes, either from an original list or from the specimen tags themselves, into the donation book of the A.P.S. Seybert then added supplemental mineralogical comments augmenting Lewis’s original specimen descriptions.^[15]Moulton, Vol. 3, 473–478. Lewis, during a visit to Philadelphia in the spring and summer of 1807, had access to the donation book, so it may be assumed he reviewed these transcriptions and was satisfied as to their accuracy.

Later Specimens

The journals make clear that mineral specimens were collected after the expedition left Fort Mandan on 7 April 1805. Evidence for this can be found in the previously mentioned entry of 31 May 1805, about collecting a “Specimine of the Stone” in the White Cliffs area of the Missouri, as well as from Lewis’s entry for 26 June 1805, which mentions the explorers’ plan to cache minerals at the Upper Portage Camp, above the Great Falls.^[16]Ibid., Vol. 4, 334 and 335n. Lewis states that Clark’s selection of articles to be deposited included “my specimens of plants minerals &c.” collected between Fort Mandan and the … Continue reading

Unfortunately, none of the mineral specimens collected after leaving Fort Mandan were accounted for by name in the list of items sent to Washington by Lewis following the expedition’s return to St. Louis. The list, however, mentions two boxes and a tin case holding “Various articles,” which could have included minerals.^[17]Ibid., Vol. 8, 419. It is also possible that Lewis delivered the mineral specimens to Philadelphia in person in 1807.^[18]The possibility that Lewis may have personally delivered the surviving post-April 1805 specimens to Philadelphia is suggested in a letter Jefferson wrote to Peale on 21 December 1806, which states in … Continue reading Or they could have been part of a shipment Lewis sent via New Orleans to Charles Willson Peale about the time he left on the journey that ended with his death, in Tennessee, on 11 October 1809.

In a letter to his son dated 17 November 1809, Peale says that he had received “a number of Articles” from Lewis, including “some minerals.”^[19]Jackson, Vol. 2, 469–470. One can only guess why Lewis would wait three years to send these additional specimens. Nor can we be absolutely certain that the items were collected on the expedition, … Continue reading In December 1809 Peale recorded in his museum accession book a long list of “Articles collected” by Lewis and Clark.^[20]Ibid., 476. Among the sundry items mentioned are “A number of Minerals,” presumably the same ones referenced in his letter of 17 November.^[21]Ibid., 478; Memoranda of the Philadelphia Museum, 1804–1841, 43–45. Peale had recorded the pre-expedition specimens donated by citizens of St. Louis (the first shipment) in his museum accession … Continue reading In January 1810, during a visit to Philadelphia, Clark mentions finding “a fiew Minerals” while searching “for the Materials left in this City by the late Govr. Lewis, reletive to our discoveries on the Western Tour.”^[22]Jackson, Vol. 2, 490. Neither Peale nor Clark states when on the expedition these minerals were collected, but as the following discussion attempts to show, some of them were almost certainly acquired after leaving Fort Mandan in April 1805.

The expedition’s mineral specimens, which as noted reached Philadelphia in several shipments between 1805 and 1809, were ultimately acquired by the Academy of Natural Sciences and merged with its mineral collection.^[23]Moulton, Vol. 3, 473. Somewhere along the way whatever identifying tags they may have had were lost, along with knowledge of their provenance. Today, the one specimen in the A.N.S. collection we can definitively link to the expedition is the fossilized jaw of a fish, Saurocephalus lanciformis, which retained its original expedition tag. (The jaw was found by Sergeant Patrick Gass on 6 August 1804.)

Seybert’s Collection

The A.N.S. came to possess the expedition mineral collection because at least 34 Lewis and Clark mineral specimens were acquired initially by Adam Seybert, the same man tasked by Jefferson in November 1805 with examining the expedition specimens sent back from Fort Mandan. We know this because Seybert produced a handwritten catalogue, circa 1812, to accompany his large mineral collection; scattered throughout the list of nearly two thousand specimen notations are unmistakable references to the expedition, and the collector is listed as “Captn. Lewis.”^[24]See Seybert’s Catalogue of Minerals as reported in John C. Greene and John G. Burke, “The Science of Minerals in the Age of Jefferson,” Transactions of the American Philosophical … Continue reading

We don’t know how or exactly when Seybert came to possess the Lewis and Clark specimens, but one possibility should be considered. Clark’s visit to Philadelphia in January 1810 came only two months after Peale received the shipment Lewis sent via New Orleans, but the mineral specimens were apparently unlabeled—Peale states that he “expected that he [Lewis] intended to have described them on his arrival here as I did not receive any letter with them.”^[25]Jackson, Vol. 2, 470. Thus, it’s possible that Clark turned the collection over to Seybert in exchange for his expertise in identifying the specimens, with the hope that the results would be included in the proposed (but ultimately never published) scientific volume of the journals.^[26]Perhaps out of respect for the captains’ exclusive right to be the first to publish their discoveries, Seybert refrained from publishing his work on the expedition specimens. For example, there … Continue reading

Seybert was a particularly good choice because he was actively collecting minerals and was still reaping the benefits of nearly four years of study in Edinburgh, London, Paris, and Göttingen.^[27]Greene and Burke, 28. Two years later, in 1812, when Seybert set aside the study of mineralogy to pursue business interests and also to serve in Congress, he sold his mineral collection to the newly established Academy of Natural Sciences.^[28]Earle Spamer, the managing editor of the A.N.S.’s scientific publication, states that the collection was purchased in 1812 by John Speakman, a founding member of the Academy of Natural … Continue reading

Seybert’s List

A review of Seybert’s circa 1812 list of expedition specimens confirms that at least some specimens collected after April 1805 did make it back to Philadelphia. Scattered among the minerals associated with the well-documented Fort Mandan shipment, Seybert listed specimens such as “Pumice. Pacific ocean. Captn. Lewis”; “Green Clay. from the Kooskoosche River, west of the Rocky mountains. Captn. Lewis”; “Keffekill [impure clay]. found at the Wallenwaller [Walla Walla] nation on Columbia River. Captn. Lewis”; and “Magnetic Iron sand, borders of the Pacific ocean near the mouth of Columbia river. Captn. Lewis.”^[29]Seybert’s Catalogue of Minerals as reported in Greene and Burke, 29–30.

The existence of these specimens proves that the captains continued their mineral collecting west of the Continental Divide and all the way to the Pacific Ocean, refuting the disparaging opinion of some historians that Lewis and Clark neglected this essential duty.^[30]For further discussion about how Lewis and Clark historians have misjudged the captains’ geological skills, see John W. Jengo, “Mineral Productions of Every Kind”: Geological … Continue reading [See sidebar, page 21.] Noticeably absent from this list, however, is any specimen collected between Fort Mandan and the Great Falls. All the botanical specimens from this phase of the journey were cached at the Upper Portage Camp on 26 June 1805, and were subsequently ruined in a flood; the mineral specimens presumably succumbed to a similar fate.^[31]Moulton, Vol. 8, 107.

Assessing how many of the captains’ rock and mineral specimens have survived to the present day must begin with the collection at the Academy of Natural Sciences. According to the A.N.S., only “five specimens can now be ascribed certainly to this expedition, two rocks and three minerals.”^[32]Earle E. Spamer, Richard M. McCourt, Robert Middleton, Edward Gilmore, and Sean B. Duran, “A national treasure: Accounting for the natural history specimens from the Lewis and Clark Expedition … Continue reading The two rocks—Seybert Collection No. 534 (“pummice stone”) and ANSP 3916/ex Seybert Collection No. 535 (“lava”)—appear to correspond to Fort Mandan mineral specimen Nos. 62 and 67, respectively.

In the journals, the captains’ identification of lava was never correct, nor were their nearly 20 “pumice” or “pumicestone” observations actually related to active volcanism. Unlike today’s restricted definition, which classifies pumice as a volcanically derived vesicular glassy rock, the captains’ characterization of pumice apparently included any fused or baked rock (termed “clinker“), which explains why they most consistently noted its occurrence in regions where coal beds had burned and slightly metamorphosed the adjacent rock strata. Lewis deftly recognized this causal relationship when he composed a cleverly concise comment to accompany the “Lava & pummice Stone” specimen (Fort Mandan mineral specimen No. 67) sent back from Fort Mandan:

Air pockets in pumice stones and similar rocks can make them light enough to float.

Of the three documented mineral specimens identified as selenite (a clear, colorless variety of gypsum), it appears that the specimen labeled Seybert Collection No. 799 corresponds to Fort Mandan mineralogical specimen No. 6 because of its unique cross-like shape (technically termed “twinning”) and its documented date of collection of 23 August 1804. Seybert’s appended description of two other selenite specimens (Seybert Collection Nos. 803 and 804) may be in error because they were described in his circa 1812 catalogue as “Crystallized sulphat of Lime. Calumet Bluff. Missouri. Captn. Lewis,” which would place their date of collection between 28 August 1804 and 1 September 1804; according to the Fort Mandan mineralogical specimen list in the A.P.S. donation book, there were no minerals collected in that time frame matching Seybert’s “sulphat of lime” description. This includes those specimens that mention Calumet Bluff in their listed description (Fort Mandan mineralogical specimen Nos. 22 and 34) or that were identified as collected on 1 September 1804 (Fort Mandan mineralogical specimen No. 15) or from adjacent areas of “white Chalk Bluffs” or “white <Chalk> Clay Bluffs” (Fort Mandan mineralogical specimen Nos. 3, 43, 52, and 53).

Additionally, each of the expedition minerals identified by Seybert, in whole or in part, as a “sulphat of lime” have recorded dates of collection indicating they were not gathered in the locale of Calumet Bluff; these include Fort Mandan mineral specimen No. 6 (collected on 21 August 1804), specimen Nos. 13, 20, and 49 (22 August 1804), specimen No. 8 (23 August 1804), and specimen No. 35 (4 September 1804, based on mention of the Quicurre [Niobrara] River). The description of the remaining “sulphat of lime” specimen is too imprecise to be specifically assigned only to Calumet Bluffs (Fort Mandan mineralogical specimen No. 63, described as a “Specimen of a Substance extremely common & found intermix’d with the loose Earth of all the Cliffs & Hills from the Calumet Bluff to Fort Mandon”).

In summary, it appears that Seybert erred in assigning the specimens labeled as Seybert Collection Nos. 803 and 804 exclusively to an area near Calumet Bluff. Based on the information recorded in the A.P.S. donation book, these two specimens could have been collected as far downriver on the Missouri as the confluence with Floyd River (where the expedition departed on the morning of 21 August 1804) and as far upriver as Fort Mandan. As such, the description of the provenance of these specimens in future A.N.S. literature should be expanded to encompass a wider range of the potential collection localities.

To this day, most of the specimens sold by Seybert to the A.N.S. in 1812 remain segregated from the academy’s general collection of minerals—they are kept in a cabinet built for them circa 1825.^[34]Spamer, et al., 50. Could the cabinet perhaps hold samples collected on the expedition? That’s unlikely, because a catalogue of the Seybert collection compiled in 1825 (representing the specimens in the cabinet) lists 157 fewer specimens than the catalogue Seybert compiled circa 1812. One can reasonably assume that among the 157 missing specimens were those collected on the expedition, because nowhere in the 1825 catalogue is there any reference to Lewis or Clark. All or most of these 157 specimens— including those collected by the captains—were probably integrated into the academy’s general mineral collection between 1812 and 1825.^[35]To explain their absence from the 1825 catalogue, some have hypothesized that Seybert did not include the Lewis and Clark specimens in the collection he sold to the A.N.S. in 1812. (Greene and Burke, … Continue reading

Fate of the L&C Specimens

Do any Lewis and Clark specimens still exist in the A.N.S.’s general collection? It is a difficult question to answer because the academy eventually reorganized its collection, placing its non-mineralogical rock and sediment samples in a separate “petrologic” collection. Many, if not most, of the samples collected by Lewis and Clark would be classified as petrologic. In 1993, the academy’s petrologic collection was formally transferred to another Philadelphia institution, the Wagner Free Institute of Science.^[36]Spamer, et al., 51. At the time of the transfer, the academy transcribed complete information from every label in the collection; no references to Lewis or Seybert were found.^[37]Spamer, personal communication, 19 June 2002. In principle, an expert in western mineralogy could examine the Wagner specimens and identify those representative of formations along the explorers’ route.^[38]At least one specimen—the shonkinite rock collected on 31 May 1805—would be readily identifiable because of its rarity and unique mineralogy; see John W. Jengo, “‘high broken and … Continue reading Unfortunately, the entire collection was crated and placed in storage, making it inaccessible to researchers at the present time.

The captains may have collected other mineral and fossil specimens unaccounted for in the expedition literature or at the Academy of Natural Sciences.

Samuel George Morton, a physician and amateur paleontologist, makes tantalizing reference to expedition related fossils in a number of articles published between 1830 and 1842. In one, for example, Morton notes that “Lewis and Clark, in their expedition to the Columbia river, procured a few fossils at the great bend of the Missouri river.”^[39]Samuel George Morton, “Description of Some New Species of Organic Remains of the Cretaceous Group of the U. States: With a Tabular View of the Fossils Hitherto Discovered in That … Continue reading Morton has the captains collecting invertebrate fossils such as Baculites (an extinct cephalopod) and Gryphaea (an extinct oysterlike mollusk).^[40]Samuel George Morton, Synopsis of the Organic Remains of The Cretaceous Group of The United States. Illustrated by Nineteen Plates. To Which is Added An Appendix, Containing a Tabular View of The … Continue reading Unfortunately, neither of these was listed in the Fort Mandan shipment or in the A.P.S. donation book, and they do not appear in Peale’s museum accession book or Seybert’s inventory catalogues. Perhaps the fossils mentioned by Morton have a separate, unknown history of collection and disposition, or maybe he just erred in crediting the captains with these discoveries. A resolution to this question awaits the discovery of written documentation substantiating a Lewis and Clark provenance.

Despite the survival of so few Lewis and Clark mineral specimens, we can say for certain that some of them wound up in Philadelphia and that for a time they were displayed in the celebrated museum of Charles Willson Peale.^[41]The only known surviving mineral specimens collected by Lewis and Clark are among the essential expedition artifacts in Lewis & Clark: The National Bicentennial Exhibition, now touring the U.S. … Continue reading The museum had other rock and mineral specimens besides those collected by the captains. John C. Greene and John G. Burke, two historians of Jeffersonian era mineralogy, argue that the collection as a whole “must have done much to stimulate public interest in mineralogy and geology” and may have been used by Benjamin Smith Barton, perhaps the preeminent naturalist of the day, in his lectures on natural history.^[42]Greene and Burke, 37.

Most of the information on natural history in the Lewis and Clark journals lay dormant for a century, a result of the failure to produce the proposed scientific volume containing, as a prospectus put it, “the information acquired by Captains Lewis and Clarke in the several departments of botany, mineralogy and zoology.”^[43]Jackson, Vol. 2, 547–548. By 1905, when the journals were at last published in a definitive scholarly version edited by Reuben Gold Thwaites, virtually all of what the captains had discovered had been subsequently rediscovered by others.

Still, it’s reasonable to believe that the rock, mineral, and fossil specimens collected by Lewis and Clark may have positively influenced scientific inquiry; perhaps they were used to illustrate points in Barton’s lectures or motivated additional research while on display at the A.N.S.

Whatever their impact on nineteenth-century science, it is certain that Adam Seybert thought highly of them. Seybert had more than thirty Lewis and Clark specimens in his possession and attempted to identify them all. Patrick Gass’s fossil fish jaw, Saurocephalus lanciformis, was described and illustrated by natural historian and physician Richard Harlan in 1824,^[44]Richard Harlan, “On a new fossil genus, of the order Enalio Sauri, (of Conybeare),” Journal of the Academy of Natural Sciences of Philadelphia, Vol. 3, 1824, 331–337, plate 12. … Continue reading and it is evident from Samuel George Morton’s publications that the purported Lewis and Clark specimens stimulated other fossil collecting in the geographic areas where they were supposedly found. I believe that the expedition specimens played a small but consequential role in facilitating the emergence of mineralogy as a useful science. They also help validate the expedition’s role as a model for the later U.S. geological surveys of the American West.^[45]John W. Jengo, “Geological Trailblazers: Observations of Western Geology in the Journals of Lewis and Clark,” Geological Society of America Abstracts, Vol. 35, No. 6 (October 2003), 605.