Why we’re here (geology is destiny)

Laramie, Wyoming (Territory) circa 1868: Union Pacific Railroad machine shops (USGS).

[In 1881, an unhappy Bill Nye quit his job with the Laramie Daily Sentinel—the first and only paper in town—and started a competitor, naming it the Laramie Boomerang after his mule, who “always came back.” Sure enough, while the Sentinel folded in 1895, the Boomerang still shows up daily. One of its more popular features is the monthly column, Laramie’s Living History. I’ve contributed several articles, about the role of botany and geology in local history. Here’s the most recent (with a few additional photos).]

[August 12, 2017]

Anyone who has lived in Laramie long knows why we’re here: 150 years ago, the Union Pacific (UP) passed through the Laramie Valley (southeast Wyoming) during construction of the nation’s first transcontinental railroad. But that’s only part of the story. The full explanation begins much earlier, back when a fortuitous combination of mountain-building and erosion created an easy route over the Laramie Mountains—the Gangplank.

One hundred million years ago, much of Wyoming was underwater, covered by the Western Interior Seaway, which split the continent from north to south. But it was not to last. Thirty million years later the land began to rise, forcing the sea to retreat. This was when the Laramie Mountains were born, part of a long and widespread episode of mountain-building that created most of the Rockies.

For the next 10-15 million years the Laramie Mountains rose, while at the same time erosion wore them down. Such is the fate of mountains—as soon as uplift starts, erosion sets in. As much as 20,000 feet of material is thought to have been removed from the crest of the range. Streams and wind carried down the debris, depositing it on the flanks and eventually burying the Laramie Mountains in their own rubble.

It’s hard to imagine such huge changes: a sea disappearing, mountains rising, mountains worn down and buried.  But at the scale of geologic time, the Earth’s surface is dynamic, always changing. This we know, though we can’t always explain why. Many mysteries remain … for example, today’s Laramie Mountains.

Ten million years ago, when the range was mostly buried beneath a thick covering of sedimentary rocks, the east flank was a broad gently-sloping plain. That’s not the case today (think Sybille Canyon!); obviously something happened. We know that erosion resumed, but why? Perhaps the entire region was uplifted, invigorating streams. Maybe climate change brought greater precipitation. Whatever the reason, the sedimentary cover was removed during what geologists call the Great Exhumation. The Laramie Mountains were disinterred … almost.

Due to a serendipitous evolution of topography, the Great Exhumation left intact a gently-sloping wedge of sedimentary rocks in the southeast part of the range. Several million years later, on September 21, 1865, General Grenville M. Dodge, soon-to-be chief engineer of the UP, scrambled up the ridge south of Crow Creek and found himself on this wedge. He was ecstatic. Here was an easy route up the Laramie Mountains, later christened “the Gangplank.”

Looking east along the Gangplank, traversed by I-80 and the UP Railroad; added star marks contact of ancient granite in foreground and much younger sedimentary rocks behind. RD Miller photo (USGS).

Just two years after Dodge’s lucky find, on the evening of October 21, 1867, UP tracklayers entered today’s Wyoming. They barely paused at Cheyenne, pushed west up the Gangplank, wound down into the Laramie Valley, and in early May of 1868, reached Laramie City, where eager new residents had been throwing up buildings the week before. Then the tracklayers raced west, laying another 350 miles of track and establishing numerous “instant towns” before leaving Wyoming in early 1869.

Union Pacific Railroad (1905); added arrow points to the Laramie Mountains (American Heritage Center).

The Gangplank is most striking at its western tip where the younger sedimentary rocks meet the ancient Sherman Granite. Only a few hundred feet separate the drainages of Crow and Lone Tree Creeks, and, though imperceptible to us, these streams are hard at work. Every year they erode a bit more rock and soil, sending it down to the North Platte River, the Missouri, and eventually the Gulf of Mexico. In other words, the Gangplank won’t be here forever. You might want to take a look at it while you still can!

From Laramie, follow Interstate 80 east to the Summit and the Sherman Granite, which forms the crest of the range. This is ancient rock—formed from magma 1.7 billion years ago. It was exposed much later during uplift of the Laramie Mountains. I-80 stays on Sherman Granite past Blair, Vedauwoo, Tree-in-the-Rock, and Buford. Here the terrain is relatively flat, and it’s tempting to think this is the Gangplank. But road cuts and occasional blobs of granite show otherwise.

Continue past Remount Road (Exit 339) and Harriman Road (Exit 342, large quarry). Just a short distance further, before the Wyoming Department of Transportation sand/salt storage structure, is the transition to the Gangplank. But don’t slow down!! I-80 traffic is too heavy and fast for gawking. Instead, continue about three miles to Exit 345; drive to the truck parking area on the Gangplank.

At the east end of the parking area is a sign illustrating the Gangplank rising from the Great Plains onto the Laramie Mountains. The text makes more sense when you realize the sign originally stood at the west end of the Gangplank (you’ll be there soon). The slope next to the parking area reveals some of the sedimentary rocks that covered the range ten million years ago, before the Great Exhumation.

Block diagram inspired by SH “Doc” Knight, Mr. Geology of Wyoming; from sign at truck parking area.

Rocks exposed on slope are part of the Tertiary Ogallala Group.

After mastering the diagram on the sign, find the westbound frontage road at the opposite end of the parking area. Set your trip meter to zero and drive the Gangplank. At 2.0 miles, just past Mile Marker 2 (green) and near the top of the hill, you will leave the ten-million-year-old sedimentary rocks and return to the ancient Sherman Granite. Here, at the tip of the Gangplank, you can straddle more than a billion years of Earth history.

From the hilltop, the view east toward Cheyenne gives a good feel for how narrow this end of the Gangplank is. The north side (left) drops steeply down to the South Fork of Crow Creek. Lone Tree Creek is off to the south (not visible here). In the distance, the Gangplank widens and merges with the Great Plains in Nebraska.

Looking east from the west end of the Gangplank; South Fork Crow Creek on left.

More points of interest on the Gangplank, and additional driving tours of railroads past and present, are included in Railroads of Albany County—Tracking the Past. This free brochure is available at the Laramie Area Visitor Center and the Historic Railroad Depot. A scanned version is available online: http://www.laramiedepot.org/about/railroadsofalbanycounty/tabid/76/default.aspx

Editor’s Note:  This is one in a series written for the Albany County Museum Coalition that promotes interest in local cultural and natural history.  Hollis Marriott came to Wyoming in 1977 to work at Devils Tower National Monument, fell in love with the wildness of the state, and stayed. She received a master’s degree in botany from UW in 1985. Now retired, she indulges her passions for botany, geology, and the great outdoors in general.

[Blogger’s Note: It’s always a pleasure to write for the Boomerang, for I’m guaranteed an enthusiastic audience. Many residents rightfully take a great interest in local history, both human and natural. Thanks to the following for help with content and editing: Judy Knight, editor of Laramie's Living History; Albany County Railroad Historian Jerry Hansen; botanist and railroad buff Dennis Knight; and Mike Nelson of CSMS Geology Post (see link for more about Gangplank geology).

Tree of the Month: the Poison Nut Tree

Poison Nut Tree, Strychnos nux-vomica; artist unknown (BHL on Flickr).

It was Dr. William Roxburgh, botanist with the East India Company, who introduced me to the Poison Nut Tree. Actually, it was the beautiful illustration by his anonymous artist-assistant, now on Flickr. And to be honest, the chilling scientific name grabbed me first: Strychnos nux-vomica. That's strychnos as in strychnine (the poison’s name was derived from the plant’s), and nux-vomica for the deadly, nausea-inducing seeds (nuts, nux).

Roxburgh arrived in India in 1776, having been hired by the Company as a surgeon (physician). He also was a botanist, and it appears he did as much botanizing as doctoring. His dream job landed in his lap three years later, when the Company’s Madras botanist retired. Roxburgh gave up medicine, and moved to the coast of Coromandel, on the Bay of Bengal. It was a botanist’s paradise, with a diverse, fascinating, and—perhaps best of all—unknown flora.

The Company’s interest in the Coromandel coast was understandable. Areas rich in natural resources lay in close proximity, and the mouths of several rivers served as ports. Surprisingly, given how long Europeans had been in India, the flora was poorly known. It was hoped that species of value would be discovered—“such articles as may prove beneficial to the inhabitants as well as the natives of Great Britain, and which ultimately may tend to the extension of the national commerce and riches.”

Building on the work of his predecessor, Roxburg explored, collected plants of interest, and wrote descriptions that included features useful for identification.

“Leaves opposite, short petioled, round-oval, shining, smooth on both sides, entire, three-five-nerved, differing in size, from one and a half to four inches long, and from one to three broad. Stipules none. Flowers small, greenish white, collected on small terminal umbells …”

“Berry round, smooth, size of a pretty large apple, covered with a smooth somewhat hard shell, of a rich beautiful orange colour when ripe, filled with a soft jelly-like pulp. Seeds from two to five, immersed in the pulp of the berry.”

Roxburgh also noted native uses of plants.

“The wood of this tree is hard and durable, and is used for many purposes by the natives. It is exceedingly bitter, particularly that of the root, which is used to cure intermitting fevers, and the bites of venomous snakes (1) … The seeds are employed in the distillation of country spirits, to render them more intoxicating.”

This use of Strychnos seeds in alcoholic beverages is intriguing. True to its name, the Poison Nut Tree’s strychnine-laced seeds (nuts) are toxic. Even a single seed reveals its evil nature within minutes: racing heart, rapid breathing, convulsions, and muscular spasms with grotesque arching of the back and neck. (Contrary to the specific epithet, nux-vomica, nausea is rare.) Death almost always follows—through cardiac arrest, respiratory failure, multiple organ failure, or brain damage. The drama of death by strychnine has made it popular with murder-mystery writers, including Agatha Christie and Arthur Conan Doyle.

Strychnos seeds are rock-hard; unless crushed before consumption, they pass through intact (source).

Roxburg needed illustrations to go with his plant descriptions, so he hired native artists. In a sense, these artists were skilled botanical illustrators; plants, leaves, and flowers were common motifs in the exquisite patterns popular in Indian artwork. But left to their own devices, they produced illustrations in their own style—bold contrasting colors, plant parts appealingly arranged, and almost nothing to provide a sense of depth. Details important to botanists were often omitted when not critical to overall composition.

Floral decoration on tomb of Empress Noor Jahan, Taj Mahal (Wellcom Trust).

More realistic plant portraits were required, with shading and depth, and with all parts necessary for identification shown in detail. So the Indian artists were given training in proper botanical illustration. The result was what Richard Mabey (2015) called “cultural fusion … an exotic fusion of European precision and Mughal stylisation that revelled in the pure patterning of plants.” Critical botanical details were included, but in an appealing composition. This hybrid style is distinctive enough to have a name: Company Art.

Sappan, Caesalpinia sappan; artist unknown (BHL on Flickr).

Strychnos nux-vomica: Company Art (left) and a more traditional illustration, from Köhler’s Medizinal-Pflanzen, 1883 (source).

Roxburgh was a passionate botanist and hard worker. From 1791 through 1794, he shipped parcel after parcel of descriptions and illustrations to the Royal Botanic Gardens, Kew, in London—500 species in all. From these, the distinguished botanist and President of the Royal Society, Sir Joseph Banks (2), selected 300 for publication.

Plants of the Coast of Coromandel was published over a period of 25 years, 1795–1819. It was a grand three-volume set, with detailed descriptions and hand-painted copper engravings—a full-page illustration for each of the 300 plant species. In the Preface, botanist Patrick Russell praised Roxburg’s dedication: “Such commendable zeal in the service has not passed unnoticed by the Court of Directors [of the East India Company], which has lately honoured him with a handsome present of botanical books, as well as with other marks of approbation.”

Russell also recognized the contributions of pioneering botanist John Gerard Koenig, “to whom Indian Botany stands so highly indebted.” But nowhere were the botanical illustrators acknowledged, nor even named. The only reference was this: “[Roxburgh] had retained a painter constantly employed in drawing plants …”

The size and lavishness of Plants of the Coast of Coromandel guaranteed it would be accessible only to the privileged—wealthy enthusiasts, and individuals associated with botanical gardens and other institutions. But fortunately, times have changed. Dr. Roxburg has joined the open access movement! Now, anyone with internet access can indulge themselves in Coromandel plants and elegant Company Art.

Flame of the Forest, Butea superba; artist unknown (BHL on Flickr).

In 2007, Plants of the Coast of Coromandel from the Missouri Botanical Garden’s Rare Books Collection was digitized, and added to the Biodiversity Heritage Library (BHL). Six years later, the illustrations were uploaded to Flickr. It was on Flickr that I met Dr. Roxburgh and the Poison Nut Tree, through my role as a tagger.

In building online collections, machines and software do the lion’s share of the work, but there are tasks that only humans can do. A machine can scan a page of text, which is then interpreted by optical character recognition software. Plant names can be flagged in the process. But illustrations are incomprehensible, and so the plants remain hidden and undiscoverable until tags are added, by a human. Only then will they show up in searches.

Most days I spend a little time, usually less than 30 minutes, adding tags for names and geographic information to illustrations by Roxburgh's anonymous artists, slowly progressing through the plants of the Coromandel coast. Gorgeous engravings of exotic plants more than make up for any tedium. The challenge of updating 18th-century nomenclature also keeps me from getting bored.

I started tagging because of its worthiness. I use online collections regularly—specimens, literature, images—so I know the value of tags. But soon there were other reasons to continue. I enjoy reading accounts of botanical exploration in the 18th and 19th centuries, and I love the exotic plants and delightful artwork.

Rosy Milkweed Vine, Oxystelma esculentum; artist unknown (BHL on Flickr).

The Biodiversity Heritage Library needs more taggers!! No experience required—taggers range from fledgling citizen scientists to professionals. The Flickr collections include many kinds of organisms, not just plants, so you can work on your favorites. Want to learn more? Check out this example, a persuasive post about the value of tagging, and the BHL Tagging Tutorial.

Footnotes

(1) Strychnos nux-vomica is recognized in alternative medicine circles as a treatment for many conditions, but most claims aren't supported by experimental evidence. However, one study found that whole-seed extract of S. nux-vomica—in low doses—effectively neutralizes venom from the viper Daboia russelii (in mice; Chatterjee et al. 2004).

(2) The first version of this post mistakenly assigned responsibility to Joseph Hooker.

Sources

Mabey, R. 2015. The Cabaret of Plants. WW Norton & Co.

Roxburgh, W. 1795-1819. Plants of the coast of Coromandel: selected from drawings and descriptions presented to the hon. court of directors of the East India Company. http://www.biodiversitylibrary.org/bibliography/467#/summary Accessed 7 Aug 2017.

Wikipedia. Strychnos nux-vomica, and Strychnine. https://en.wikipedia.org/wiki/Strychnos_nux-vomica; https://en.wikipedia.org/wiki/Strychnine Accessed 7 Aug 2017.

This is my contribution to the August gathering of tree-followers kindly hosted by The Squirrelbasket.