Thursday, June 3, 2021

Is there beauty in the Great Basin?

"I begin to think the Great Basin, like many other great things in this world, a great humbug ... very interesting to the geologist and geographer, but dreadfully wearisome to the traveler, as we can attest." Cornelia Ferris, 1853

In his wonderful book, The Broken Land, geologist Frank DeCourten begins Chapter 1 by asking why and where we find beauty in nature. Why do the "vistas of sagebrush and mahogany-colored mountains" of the Great Basin that he finds so "thrilling" bore or even repel most travelers? Perhaps it is as Thoreau says—there is only "as much beauty visible in the landscape as we are prepared to appreciate ...".

DeCourten goes further, asserting that beauty and its appreciation will increase with a deeper understanding of the landscape. I agree. With each visit to the Great Basin, the landscape becomes more engaging and grand as my "geological enlightenment" grows.

The Great Basin; note the many "caterpillars" lined up southwest to northeast (by Kmusser).

It was a more recent DeCourten book that inspired my latest trip to the Great Basin—Roadside Geology of Nevada, coauthored with Norma Biggar (2017). Actually this was a second try, after a trip two years ago was aborted due to snow and more snow. This time the weather cooperated marvelously, and I spent two weeks in a geological wonderland with much that was beautiful. Just look!

The Devils Gate Limestone, beautifully exposed along Highway 50, formed from sediments deposited 370 million years ago in shallow water just off Laurentia (North America). At that time the continent was smaller, the west coast located in today's Utah. Millions of years later, the horizontal beds were tilted and then revealed by erosion ... lucky for us!

Devils Gate west of Eureka.

About ten miles north of Devils Gate, near Tyrone Gap, I was stopped in my tracks by more tilted beds, these approaching vertical! The rock is silicified conglomerate dating from 300 million years ago—once-horizontal beds of sediment eroded off the Antler highlands (mountains now long gone).

Steeply-tilted conglomerate of the Garden Valley Formation.

Nevada's accreted terranes were a new experience for me—further enlightenment :) These are chunks of crust that rafted in from somewhere and were plastered onto the continent, extending North America west by hundreds of miles. Chalk Mountain (not chalk but dolomite) was carried here on the Paradise terrane, which arrived sometime in the Mesozoic (the dolomite has been dated as late Triassic).

Chalk Mountain (actually dolomite) ended up here from parts unknown. 

On the heels of the Paradise terrane came the Sand Springs terrane, mostly deep water sedimentary rock (shale) that was metamorphosed to slate and phyllite. The platy rocks shone and sparkled in the sunshine, which I enjoyed immensely! But my camera had trouble capturing their darkness. It did better with my souvenir.

Phyllite outcrops just west of Sand Springs Pass on Highway 50.

The Pine Nut terrane is easily accessed via Highway 338—a bit out of the way but worth the trip! At Milepost 6, it squeezes between two large Pine Nut outcrops. There's room to park and not much traffic. These were once volcanic rocks of a marine island arc, metamorphosed during accretion probably. Among my souvenirs is a beautiful rock whose contortions testify to its mysterious but exciting past.

Pine Nut terrane 6 miles east of California.
The rock on the right is my favorite currently.

Many of the outcrops I saw were volcanic, products of huge violent eruptions that took place during an episode of volcanism lasting 25 million years. Viscous magma exploded from giant calderas, covering the land in thousands of feet of ash so hot that it was welded into rock. It was Hell, right here on Earth!

Tuff erupted 28-25 million years ago; now beautifully eroded and exposed in Gabbs Valley Range.

On top of all this craziness, the continent here is undergoing extension. For reasons still debated, the Great Basin is being stretched, and Nevada is now nearly twice as wide as it was 30 million years ago. In the process, basins drop and mountain ranges rise (creating the caterpillars in the Great Basin map above).

This stretching and buckling hasn't stopped. Just 67 years ago, a magnitude 7.2 earthquake boosted Fairview Peak 7–20 vertical ft; the ground moved 3–13 ft horizontally as well. A beautiful fault scarp is clearly visible from the gravel road along the base.

Fairview Peak earthquake fault scarp.

As a summary, I offer this final photo. Ash flow tuff exploded from a caldera 32 million years ago now frames the distant Toiyabe Mountains, where Paleozoic metamorphosed marine sediments intruded by Mesozoic granitics are rising as the land continues to stretch. Yes, there is beauty in Great Basin ... lots of it!

View west across the Big Smoky Valley, from the mouth of Northumberland Canyon.

Sources

DeCourten, F. 2003. The Broken Land; adventures in Great Basin geology.

DeCourten, F. and Biggar, N. 2017. Roadside Geology of Nevada.

Ferris, Cornelia. 1853. From Ferris & Ferris 1856, The Mormons at Home: With Some Incidents of Travel from Missouri to California, 1852-3. In a series of letters.


Tuesday, May 11, 2021

Danny's Rock Tree

Tree-following (kinda).

I'm on the road, so instead of reporting on my followed trees, Flash and Spike, I introduce you to Danny's rock tree, next to an irrigation ditch in the Grand Valley (western Colorado). The rocks hang by thin steel cables. When the wind blows, they twirl—back and forth, back and forth.


As for my trees ... when I looked the day I left, Flash (maple) had plump buds with pink tips. Spike (hawthorn) hadn't changed.

More news from other tree-followers available here.


Monday, April 26, 2021

Herbarium: The Quest... (a book review & more)

In the early 1980s, Barbara Thiers, Director of the William and Lynda Steere Herbarium (NY Botanical Garden), and 15 other prominent botanists were asked to come up with a timeline for the history of herbaria. But in spite of centuries of combined education and experience, they failed. They couldn't agree on mileposts, and soon realized how little they knew!

You, however, can avoid this situation if you read Thiers's book: Herbarium: The Quest to Preserve and Classify the World's Plants (2020). As well as being edified, you will be much entertained as you travel from the first herbarium—a modest book—to today's 3300 institutions spread across the globe, home to 390 million dried pressed plants.

Herbarium?

Probably there are readers who are unfamiliar with herbaria (plural for herbarium). But rather than resorting to a definition, let's start with their birth, proceed through their development, and ponder their future. That will be far more interesting!
Saffron, from Dioscorides's De Materia Medica, the standard European botanical textbook for 1500 years (Codex Julianae Aniciae edition, ca. 515 AD; Wellcome Collection).
It's thought that botany professor Luca Ghini, of the University of Bologna, invented the herbarium in the 1520s, during the exciting early days of the Italian Renaissance. He wanted a better alternative to standard botanical pedagogy, lectures based on Discorides's De Materia Medica (above), first published in 65 CE. So Ghini brought fresh plant material to class. Many more details could be seen, making identification much easier and endearing him to his students.

Ghini had another brilliant idea—a "hortus hiemalis" or "hortus siccus" (winter or dry garden), now known as "herbarium". This was a collection of dried plants suitable for study in winter. Each plant was carefully arranged in a natural pose between sheets of paper, and placed under weights to press it flat. When fully dry, plants were glued to blank pages in a bound volume, a book herbarium.
Tomato plant from the En tibi book herbarium (ca. 1558)—"a smiling garden of everlasting flowers" made by one of Ghini's students, Francesco Petrollini. Naturalis Biodiversity Center.

A century later, plant collecting had become popular enough that naturalist John Woodward saw fit to publish Brief Instructions for Making Observations in All Parts of the World, as also, for Collecting, Preserving, and Sending Over Natural Things (1669). His title hints at a cause of the increase: European ships were crossing the seas in global exploration. Plants were of great interest, being sources of valuable commodities such as food, flavorings, fine woods, fiber and dye, and seeds and plants for the garden. Usually there was a botanist on board.

Woodward's instructions weren't all that different from today's. Collectors should select plants suitable for identification. "Chuse all these Samples of Plants when they are in prime, I mean in Flower, Head, or Seed, if possible; And if the lower or ground Leaves of any Plant be different from the upper leaves, take two or three of them, and put them up along with the Sample" (more here). Plants should be pressed soon after returning to camp (or the ship), to preserve structures, and possibly color, after carefully arranging them so that parts don't overlap.

Field botany—not for the faint of heart

At this point, Thiers's book takes on a new character—many, actually. The history of herbaria would be as dry as the specimens they contain if we ignored the characters who collected them. Or, as the author says, "the sometimes odd and loveable people who have helped build the world's herbaria."
William Dampier ca. 1697, holding A New Voyage Round the World, the first of seven books he would write (National Portrait Gallery, London).
Englishman William Dampier was a pirate, privateer (authorized pirate), navigator, naturalist, and all-round adventurer. In 1699, he was placed in command of the rickety 9-year-old HMS Roebuck, and directed to sail to the east coast of New Holland (Australia) to collect herbarium specimens, among other things. After rounding the Cape of Good Hope, Dampier traveled to western Australia and nearby archipelagos, where he found many plants of interest.

But then just 100 miles from Australia's east coast, his intended destination, he was forced to turn back, for the Roebuck was in serious disrepair. The trip home was no fun. Among other things, the ship sank, stranding Dampier and his crew on Ascension Island for five weeks. Most of his specimens were lost.

Several preeminent botanists studied and classified those that survived, giving them Latin(ized) names as we do today. But these names were intended to be descriptive, with enough words to distinguish the new plant from its (presumed) relatives, for example, "shrubby long-leaved horsetail of New Holland" (image below). As more plants were discovered, the names got longer.
Upper left is the Equisetum Novae Hollandiae frutescens foliis longissimis mentioned above. From Dampier's A Voyage to New Holland ... in the year 1699 (courtesy Biodiversity Heritage Library (BHL)).
Have another look at this image. The plant lower right is Mohoh Insulae Timor, described by Dampier as "a very odd Plant, agreeing with no describ'd genus." Any ideas what it might be? You can study the specimen here, courtesy Oxford University. Notice both the well-preserved 320-year-old plant, and the many annotation labels added, as later botanists tried to identify it.

A quiet interlude

The original names of Dampier's plants would be abandoned just 50 years later, thanks to another memorable character—not so much a traveler but an intellectual adventurer. In 1753, Carl Linnaeus published Species Plantarum, establishing a naming system still in use. With no aspirations for description, he limited names to two words: genus and specific epithet. So Equisetum Novae Hollandiae frutescens foliis longissimis became Casuarina equisetifolia (not a horsetail but a whistling pine). However, of greater interest to us are Linnaeus's contributions to "botanical infrastructure" as Thiers calls it.

Linnaeus's innovations weren't limited to botany. For example, he's thought to be the inventor of index cards. In compiling information about various items, it's far better to write on cards that can be intercalated and rearranged, rather than on pages fixed in a book. Linnaeus applied this principle to herbaria as well, mounting plants on paper sheets, and then filing them with related specimens. Thus the collection was kept ordered by species, genus and family as new specimens were added.
Linnaeus recommended a specific design for herbarium cabinets (from Philosophia BotanicaBHL).

More colorful characters

From Linnaeus's quiet study, Thiers returns to the high seas of the 18th century, traversed by botanical adventurers obsessed with plant collecting and discovery. Given the many dangers and challenges, it's not surprising they were a tough and quirky bunch.

Consider Jeanne Baret—a French peasant, highly-skilled "herb woman" and one of two naturalists on the Bougainville expedition (1766-1769). This was the Age of Enlightenment; reason and "philosophy" (today's science) were highly valued. Is this why there were two botanists on board? Not at all; Baret had snuck on! The French navy banned women from ships, as they were sure to bring bad luck.
"Jean" Baret, a young sailor (source).
However, being lovers and sharing a passion for plants, Baret and chief botanist Philibert Commerson were inseparable. So she dressed as a young sailor, took the name of "Jean", and showed up on the dock, where Commerson went through the motions of interviewing and hiring her him as assistant. They sailed west to South America and rounded Cape Horn, stopping periodically to explore and collect. Next, they crossed the Pacific, landing in Tahiti malnourished and suffering from scurvy. After a pleasant period of recovery, they continued west for more exploration and collecting.

Commerson proved to be frail and unhealthy, so Baret did most of the field work, "hiking long distances in pursuit of plant specimens while carrying a musket, a supply of food, and a field press and paper for the press." She managed to conceal her true sex for much of the journey, possibly by declaring herself a eunuch. But by the time they arrived in Mauritius, she was noticeably pregnant. I will leave it to Thiers to tell the rest of Baret's remarkable adventure.
José Celestino Mutis (1732-1808). Oil painting by R. Cristobal, 1930 (Wellcome Collection).
An especially admirable field botanist in my opinion was the priest, mathematician, naturalist, artist, and physician José Celestino Mutis. Born and educated in Spain, he spent most of his life in New Granada (northern South America). In 1783, after campaigning for twenty years, Mutis persuaded Spain to fund botanical exploration. The project would last 34 years, cover 50,000 miles, yield 24,000 collections, and earn him appointments to prestigious European scientific organizations thousands of miles away.

For his botanical illustrations, Mutis trained, employed and credited indigenous artists. Their style was distinctive, both beautiful and technically accurate. Sympathetic to the Revolution (against Spain), Mutis wanted these illustrations, along with his papers and specimens, to remain in Bogotá. But that was not to be. Somewhere along the way, his specimens were destroyed. Or so it was thought ...
Mandevilla subsagittata, a rocktrumpet, by Juan Francisco Mancera, one of Mutis's illustrators. Real Jardín Botánico-CSIC

Thiers mentions Alexander von Humbolt and other well-known explorer-naturalists only briefly, instead focusing on the under-appreciated, for example English botanist Richard Spruce. He spent 11 years in South America, in lowlands and mountains, often traveling alone. In the Andes of Ecuador, he collected seeds and plants that launched Cinchona (quinine) plantations in south Asia, to the great benefit of malaria sufferers. But Spruce's true love was liverworts (Hepaticae in his day). He studied them until his death, struggling in poor health to observe and describe their minute details.
"It is true that the Hepaticae have hardly as yet yielded any substance to man capable of stupefying him, or of forcing his stomach to empty its contents, nor are they good for food; but ... they are infinitely useful where God has placed them, as I hope to live to show; and they are, at the least, useful to, and beautiful in, themselves—surely the primary motive for every individual existence."

Radula gottscheana, a leafy liverwort (plant in center, ~life-size); from Richard Spruce's The Hepaticae of the Amazon and the Andes of Peru and Ecuador (BHL).

Herbaria—now a global phenomenon

In spite of being enamored with with the great 19th-century naturalists of North America, I now jump ahead to China, part of Thiers's tour of herbaria beyond Europe and the United States (she also includes Australia, Brazil and South Africa). But first, consider this mystery: Why is it that in spite of thousands of years of accumulated plant knowledge in China, long predating that of Europe, herbaria there were so long in coming? Why were Europeans the first to preserve dried plants for study? Thiers has a theory, but only a theory. Any ideas?

From Li Shizhen's Bencao Gangmu (Compendium of Materia Medica); 1593 CE (top) and 1800 CE (source).

The earliest surviving Chinese plant book is a 2500-year-old herbal (above, top). It contained accurate descriptions and illustrations, as well as information about cultivation and medicinal use. New editions were printed roughly every century, expanded to include more plant species and updated knowledge. So when the Europeans arrived, they found both new (to them) plants and lengthy written accounts about them. This led to trouble.

Soon Britain traders, already established in India, were determined to gain access to the Chinese interior with its many valuable plants. The led to the notorious Opium War, and the establishment of British stations across China. Plant collectors went crazy. For example, physician Augustine Henry, with the Imperial Customs Service, collected 15,000 specimens in 15 years, representing 5000 species of which 500 were new to [western] science.

Emmenopterys henryi, a tree in the Rubiaceae "discovered" by A.M. Henry in China (BHL).
After the abdication of the last Chinese Emperor in 1912, botany (and science in general) progressed rapidly, including establishment of the first Chinese herbarium in 1915. But during World War II, many specimens were destroyed or stolen. Botany and prominent botanists suffered greatly during the Cultural Revolution as well.

But recovery was rapid! China now boasts 361 herbaria holding 20 million specimens, which are steadily being digitized. The 80-volume Flora Reipublicae Popularis Sinicae was completed in 2004. An English version, a collaboration between the Institute of Botany in Beijing and the Missouri Botanical Garden, was completed in 2013 and is now available online at efloras.org.

What does the future hold?

Thiers ends her book by promoting herbaria and their many uses, and by pondering their future—very much a relevant issue for Wyoming plant lovers currently. In case you haven't heard, the state of Wyoming is to receive a big chunk of Federal stimulus money. There's talk that some of it will be used to enlarge the Rocky Mountain Herbarium at the University of Wyoming! Fingers crossed!!


Herbarium: The Quest to Preserve and Classify the World's Plants, by Barbara Thiers, is available in print or digital format at the standard outlets. Originally priced at $40 and $17, prices for the print book are dropping, so shop around.

Wednesday, April 14, 2021

Tree-following in April—Peak Laziness

My trees, Spike and Flash, have done nothing that's obvious to humans. I give them water during warm spells, hopefully they're putting it to good use. I check the buds most days. But this morning I just took a photo through the window, which explains the faint grid. That's Flash on the left, by my truck; Spike on the right.

Again we have fresh snow, just like in my report a month ago. And again we're happy. Everything has been so dry here in the Laramie Valley.

Travelers are not happy however. Again Interstate-80 is closed, another rolling closure. If you have 1:34 min:sec to spare, check out WYDOT's Ralph Tarango and Doug McGee explaining rolling closures. They do a good job. And "Remember, if there's ice & snow, take it slow!"
Curtis Street exit, Laramie, Wyoming (WYDOT).


Friday, April 9, 2021

Mapping the Laramie Plains II: 3rd dimension captured

Two views of Sheep Mountain[s]: 1895 USGS map and 2011 photo looking northwest from Sodergreen Lake.

To refresh your memory, and for you who missed Mapping the Laramie Plains I: in pursuit of the 3rd dimension, this story began with the promise of a map of the Laramie area on which "almost every hill and cañon [sic] can be determined at a glance!" according to the Laramie Boomerang in 1893. Yet the post ended before we could share in the reporter's excitement. That's because the back story was so long—three millennia.

It began in the 12th century B.C., when Egyptian scribe Amennakhte drew the earliest surviving topographic map—a map which shows the shape of the land. It featured a winding line with large flat cones on either side—a valley bottom between hills. Maps would be similarly crude for the next three thousand years, with hills and mountains drawn as simple pictures, and approximately located at best.

But by the early 1800s, techniques were  much improved. Maps by William Clark of the Lewis and Clark expedition, and Charles Preuss, John C. Frémont's cartographer, added significantly to our geological knowledge. But they weren't perfect. Clark put today's Colorado too far north, thereby eliminating the Laramie Plains. Preuss's map was accurate for major features, but finer details could be unreliable. And on both maps, mountains were shown using hachures—short parallel lines suggesting relief but with little specific information. The third dimension remained elusive.

Excerpt from Preuss's map, showing the Laramie Plains crossed by the mysterious Right Hand Fork of the Laramie River (state line added). David Rumsey Map Collection.

After a grim hiatus, mapping resumes

Through the 1850s, the Army Corps of Topographical Engineers continued to explore and map the American West. The emphasis was route-finding, exemplified by the Pacific Railroad Survey—four concurrent expeditions looking for a way across the Rocky Mountains. But mapping came to a halt with the start of the Civil War, except as needed by the Union Army.

About five years after the War's end, the government began to invest again in maps. They were badly needed, for while France and England were putting final touches on national maps, and a dozen more countries had surveys in progress, the United States lagged far behind.

In 1870, a young US Army Lieutenant, George Montague Wheeler, presented a detailed proposal to map the United States west of 100º longitude (which roughly bisects the Dakotas). In need of post-war work, the Corps of Topographic Engineers jumped at the opportunity, and in 1871, Wheeler launched his "Survey West of the One-Hundredth Meridian."

George Montague Wheeler ca. 1872; National Portrait Gallery (SI)

Where on Earth are we?

Just a year later, on November 30, 1872, James H. Hayford of the Laramie Daily Sentinel reported, "Some parties are putting up some aparatus [sic] and a temporary observatory near our office today, under the supervision of Lieut. Wheeler [it's unlikely Wheeler himself was present], for the purpose of taking some astronomical observations to determine the latitude and longitude of this place."

Wheeler's men, John H. Clark and F.R. Simonton, had already made astronomical observations at two other locations in Wyoming Territory: Fort Fred Steele and Cheyenne, where they came up with a handy improvement to standard procedure. "A large wall-tent drawn over a framework formed the observatory. ... it was found to be an improvement to retain the ridge-pole [during observations] as a support against the violent winds so prevalent."

All in all though, working conditions were luxurious compared to those of the Frémont expedition 30 years earlier. Clark and Simonton could partake in the conveniences offered by the Laramie City, just four years old. Furthermore, their tent "was furnished with all the appliances of a field and temporary observatory, such as stools, stands, tables, and the like, and nothing was wanting as to equipment for first-class field-work. The [local] telegraph company furnished the line."

Longitude by wire

However, one thing hadn't changed since Frémont's time—longitude remained the greater challenge. There was no way to measure it directly. Instead, it was calculated based on the difference in time of specific celestial events in Laramie, and in Salt Lake City where longitude had been determined in 1869. [If you are thinking Laramie and SLC are in the same time zone, you're correct. But for this procedure, the surveyors used local time, also called solar time.]

To determine time difference, Clark and Simonton relied on the near-instantaneous communication of telegraphy. Time was recorded by chronograph—a combination of chronometer (clock) and paper-covered cylinder. Powered by a small battery, the cylinder turned exactly once per minute, as a pen marked a chronometer tick every second. After each minute, the pen-holder advanced slightly. The result was a piece of paper covered in parallel lines of tick-marks, a printed record of time.

As the chronometer clicked and the cylinder turned, the men added astronomical observations to the chronograph record, in real time. One man kept an eye on the heavens while also recording meteorological conditions and other notes on a paper form. When a star to be tracked approached, he notified the Observer at the telescope. At the moment the star entered the telescope's field of view, the Observer tapped a key wired to the chronograph, thereby leaving a mark on the paper. He did the same when the star passed out of view.

Drum chronograph by William Bond & Son, ca. 1850; "an instrument that touched a pen to a paper-wrapped cylinder to record both the beats of the clock and the instant of a celestial event, signaled when an observer pressed a telegraph key." (courtesy National Museum of American History)

This was only half the project. Each time the Observer in Laramie pressed the key, the signal also was sent via telegraph to a chronograph in Salt Lake City, overseen by their coworker, E.P. Austin. From the two sets of long paper records, they determined that stars passed over Laramie 25 minutes and 12 seconds before passing over Salt Lake City, putting the Laramie observatory at approximately 105º 35' 24" longitude (only about four blocks too far east according to Google Earth, not bad for field data!).

Star-gazing in Laramie, Wyoming in December

Obviously, Clark and Simonton were able to determine longitude much more accurately than Frémont had three decades before. But the work was challenging even so. They had constructed a rigid base for their instruments, but thundering trains shook them out of adjustment, and the metal contracted and expanded with temperature. Ink froze on the coldest nights, and the men's concentration waxed and waned with weather and amount of sleep.

So for accuracy, multiple stars were observed on multiple nights—but only when skies were clear at both ends of the telegraph line. To get enough observations, Clark and Simonton spent most of December in Laramie, "subjected to too much cold and too many wind and dust storms for any human brain and muscle to effect its best work in astronomy," according to Clark.

The future arrives

Wheeler's 1877 Progress Map; published sheets are brown. Laramie is near the east edge of Sheet 43. David Rumsey Map Collection.

In just eight years, Wheeler's crews surveyed 333,000 square miles; 75 topographic atlas sheets were produced (but no Laramie Sheet). The tradition of representing relief using hachures continued, often with the addition of spot elevations (numbers). But there was a revolution afoot. During the same time, John Wesley Powell and Almon Harris Thompson, of the US Geographical and Geological Survey of Territories, were producing topographic maps using contour lines, which connected points of equal elevation. These maps showed the shape of the land in greater detail and more accurately.

Excerpt from Wheeler's hachured "Central Colorado Atlas Sheet # 62a" (1878). Click to view scattered spot elevations. David Rumsey Map Collection.
Excerpt from Powell and Thompson's contour map: "Green River from the Union Pacific Rail Road [WY] to White River [CO]" (1876); green marks irrigable land. David Rumsey Map Collection.

Mapping the Laramie Plains

In 1878, Wheeler's survey and three others were replaced with a single agency, the United States Geological Survey (USGS), tasked with "classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain." In 1882, its responsibilities were expanded to include preparation of a national map.

A decade later, on August 26, 1892, the Laramie Boomerang had great news. USGS surveyors Frank Tweedy and James McFarland had arrived and would "commence work upon the topography of this section of the country"—part of the national map of the United States already ten years underway. "This vast map will take at least 25 more years to complete [it would be more like a century] ... [and] when completed, would, if spread out, cover a little over 3/4 acre ..."

Obviously impractical, the great map had been divided into sheets, each named for a prominent local feature (for example, the Laramie Sheet). Vertical relief would be shown with contour lines, now recognized as far better than hachures, which cluttered maps, provided limited information, and were expensive to draw and print (almost as costly as fieldwork!).

No need to bother with longitude

The point established 20 years earlier, by Clark and Simonton of the Wheeler survey, did not go to waste. Tweedy and McFarland used it as the starting point for their survey. From it, they ran a baseline along the bed of the Union Pacific Railroad north of Laramie for 2.5 miles. The ties supported their tape nicely, and there was no brush to clear.

Their methods show how far accuracy had come. The tape was held at 20 lb. tension using a spring balance at one end. After every four lengths, they remeasured and calculated the average. The metal tape was precisely 300 ft long, but that was at 62º F. So they tried to work mainly on cloudy days or at night to minimize expansion and contraction. They also kept a record of air temperature, for later adjustment (0.02289456 inch per degree).

From the baseline, Tweedy and McFarland established points across the Laramie Plains through triangulation—measuring angles. No longitude determinations needed! And no trees obscured their view. They measured distance, direction and height of prominent features—mountain summits, ends of ridges, forks of creeks, and so forth. They also made detailed sketches of landscapes.

After several months, Tweedy boarded a train and transported the data and sketches to Washington DC, where he and others would turn them into a map.

Reading the lines

Six months later, in March of 1893, County Surveyor W.O. Owen  received preliminary sheets for review (Owen had mapped Albany County the decade before, using shading to show relief). According to the excited Boomerang reporter who saw them, "The contour lines are so explicit that almost every cañon and hill can be determined at a glance."

Well, maybe. For many people, contour maps were new and counterintuitive. So the USGS provided an explanation with each map to help users interpret the winding lines. "Each contour [line] passes through points which have the same altitude. One who follows a contour on the ground will go neither uphill nor downhill, but on a level ... a succession of these contour lines far apart on the map indicates a gentle slope; if close together, a steep slope; and if the contours run together in one line, as if each were vertically under the one above it, they indicate a cliff."
Excerpt from first Laramie Sheet (USGS 1895). Increasingly-close lines east of Laramie are foothills of the Laramie Range. Southeast of town, Red Buttes have dense lines on their steep sides, and none on the flat tops. Gentle terrain (lines far apart) stretches west for miles before meeting the dark steep face of Sheep Mountain.

Even the depressions of the Laramie Basin were mapped using contour lines. In fact, they are textbook examples—literally! They appeared as Plate 170B in "The Interpretation of Topographic Maps" (USGS 1908). "In many parts of the country are depressions or hollows with no outlets. The contours, of course, surround these, just as they surround hills. The small hollows known as sinks are usually indicated by hachures, or short dashes, on the inside of the curve."
Excerpt from "Plate 170B: Special types of lakes: part of Laramie Sheet" showing hollows or sinks of the Laramie Plains (USGS 1908).

Sources

These are some of the more interesting sources I found:

David Rumsey Map Collection (kinda like the Hotel California—hard to leave)


Evans, R.T., and Frye, H.M. 2009. History of the topographic branch (division): U.S. Geological Survey Circular 1341, 196 p. (PDF; unfortunately illustrations are missing)

For more about longitude determination, see the great Wikipedia article: History of longitude, especially "Land surveying and telegraphy". True enthusiasts will want to read "Longitude by Wire: Finding North America" by Richard Stachurski (2009).

Cohen, Paul. 2002. Mapping the West; America's Westward Movement 1524-1890. Hardcover. 65 fascinating maps and their stories (plus a very interesting account by David Rumsey of how he got hooked on maps).

This post is an expanded version of the second of two articles about mapping the Laramie Plains, my most recent contribution to the "Laramie History" column in the Laramie Boomerang.

Saturday, March 27, 2021

Mapping the Laramie Plains I: in pursuit of the 3rd dimension

"... almost every hill and cañon can be determined at a glance!" From first Laramie, Wyoming Sheet (USGS 1895; public domain).

In the spring of 1893, Albany County Surveyor W.O. Owen received a set of preliminary maps from the US Geological Survey for review. Owen had known what to expect, but the others who saw them were surprised. "The maps are of a very interesting character ...", wrote a reporter for the Laramie Boomerang, "almost every hill and cañon can be determined at a glance!"

Indeed, the new map was astonishing—mountains and depressions around Laramie had been clearly mapped using squiggly lines! But this achievement was long in coming. For millennia, mappers had struggled to show topographical relief, to capture the third dimension on a two-dimensional sheet of paper.

Line + cones = valley
From Amennakhte's map for pharaoh Ramesses IV. Public domain.
In 1160 B.C. Scribe-of-the-Tomb Amennakhte made a map for Egyptian pharaoh Ramesses IV, who was planning a trip to quarry sandstone suitable for statues. On papyrus, he drew a broad winding line with bumpy cones lying flat on either side. With a bit of imagination, we see this is a valley lined with hills.

Amennakhte's hills look terribly crude to our eyes. Yet they aren't all that different from those appearing on maps for the next two millennia. As late as the 16th century, during early exploration of North America, mountains were shown as oversized cones, though sometimes shaded to suggest depth. Often their locations were based on distant views from sea, or rumors.
Leftmost figure is "Royal Scribe of the Place of Truth" Amennakhte. Carving on limestone, ca. 1184–1070 BC. Metropolitan Museum of Art; public domain.

Lewis & Clark map new territory

The next centuries brought significant improvements in surveying and mapping, fortunately. In the early 1800s, the young United States was in desperate need of good maps. The Louisiana Purchase had doubled the country's size. Little was known about the new territory—not even its size, nor how to traverse it.

In May 1804, the Corps of Discovery Expedition, led by Meriwether Lewis and William Clark, headed up the Missouri River in search of a route to the Pacific Ocean. In preparation for the trip, Lewis was trained in celestial navigation. President Thomas Jefferson personally provided instructions for mapping:
"... you will take observations of latitude & longitude, at all remarkable points on the river [e.g., rapids, river mouths, islands]. The interesting points of the portage between the heads of the Missouri, & of the water offering the best communication with the Pacific ocean, should also be fixed by observation ..." [Jefferson assumed they could reach a west-flowing river by carrying their boats overland.] "Your observations are to be taken with great pains & accuracy, to be entered distinctly & intelligibly for others as well as yourself, to comprehend all the elements necessary, with the aid of the usual tables, to fix the latitude and longitude of the places ..."

Lewis and Clark faithfully executed Jefferson's instructions, for three years, four months, ten days and 8000 miles.

William Clark, explorer, soldier, Indian agent, territorial governor & cartographer; portrait by Charles Peale 1810. Public domain.
Clark's map reveals a multitude of mountains

William Clark took on the job of mapmaker. In addition to the Expedition observations, he used information from explorers, trappers, natives, and earlier maps to include areas not covered by the expedition. His first map showed the Corps’ route in great detail and was necessarily huge—50+ large sheets. He then produced a single map 52 inches long and 31 inches wide, engraved and published in 1814: “A Map of Lewis and Clark's Track, Across the Western Portion of North America ...”

Among the discoveries visible on Clark's map is the structure of the Rocky Mountains. They are not a single long ridge as previously thought, but a complex system of mountain ranges and foothills. In fact, after reaching the headwaters of the Missouri, the Corps of Discovery had to travel for weeks on horseback and foot to reach west-flowing waters. A portage across the Rockies was out of the question (click on image below).
Lewis & Clark's Track. Courtesy David Rumsey Map Collection (available in high resolution).
If you click on these images, you can see that mountains were drawn with hachures—short parallel lines looking something like eyelashes. Length and curvature gave a sense of height and steepness. Hachures were denser and darker on east and south slopes of ranges, suggesting a third dimension.

Clark's map was mostly accurate by the standards of the day. But there is a glaring error in the southern part. The Laramie Plains and surrounding mountains are missing! Little was known about the territory that would become southern Wyoming, so future Colorado and Kansas were moved north to fill the gap. This is why the Kanzas [sic] River was shown flowing where Rawlins and Laramie are today.

Today's southern Wyoming, from Lewis & Clark's Track. The Arkansas and Kansas Rivers were mapped hundreds of miles northeast of their true location, putting them in the vicinity of modern-day Rawlins and Laramie (added). Courtesy David Rumsey Map Collection.

The Pathfinder puts the Laramie Plains on the map

John C. Frémont "on the Rocky Mountains"; public domain.

In July 1843, a small contingent of the US Army Corps of Topographical Engineers climbed out of the canyon of the Cache-à-la-Poudre River, where they had hoped to find a route over the Rocky Mountains. Instead, they crossed the broad divide to the north.

In command was a young ambitious lieutenant—John Charles Frémont, the Pathfinder. This was the second of five expeditions he would lead through the American West, each time making significant contributions to geographical knowledge. He also would be court-martialed, lose a presidential election, squander large sums of money in mining schemes, and die in poverty. But all that was far in the future on that lovely summer day when the Laramie Plains came into view.

"The weather was pleasant and cool, we were disturbed by neither musquitoes [sic] nor flies; and the country was certainly extremely beautiful," Frémont would write in his report. "The slopes and broad ravines were absolutely covered with fields of flowers of the most exquisitely beautiful colors. ... As we emerged on a small tributary of the Laramie river, coming in sight of its principal stream, the flora became perfectly magnificent; and we congratulated ourselves, as we rode along our pleasant road, that we had substituted this for the uninteresting country between Laramie hills and the Sweet Water valley."

Challenges: stones, sagebrush, longitude

That evening, they camped on the Main Fork of the Laramie River, where Frémont took astronomical readings to determine latitude and longitude. While latitude seems to have been accurate, his calculation of longitude put them too far west, in the Medicine Bow Mountains near Lake Owen according to Google Earth. But that's not surprising. Estimating longitude was difficult, requiring careful tracking of stars with a precision telescope and a chronometer that kept steady time, or at least lost time at a steady rate.

For three days the party traveled northwest along the Medicine Bow mountain [sic]. The going was easy at first, but near the mountain they were slowed by large round stones in the soil. Equally difficult were ridges "made extremely rough by the stiff tough bushes of artemisia tridentata, in this country commonly called sage" [as it is today].

On August 2, they camped on the Medicine Bow River near "an isolated mountain called the Medicine Butte [Elk Mountain], which appeared to be about 1,800 feet above the plain, from which it rises abruptly, and was still white nearly to its base with a great quantity of snow". Frémont made more astronomical observations, this time including "an immersion [eclipse] of the first satellite of Jupiter." Even so, the calculated longitude again put them too far west.

After passing south of Elk Mountain, the party dropped down to the North Platte River, followed it to the Sweetwater, and continued on to California and Oregon. They would return home in August 1844, after about 15 months and 10,000 miles of travel.

A "meagre and skeleton" but valuable map (Frémont & Preuss 1845). High resolution version here, courtesy David Rumsey Map Collection. 

Dramatic report, spectacular map

Frémont wrote a colorful report about his adventures, with the help of his wife, Jesse, whose father—the powerful Senator Thomas Hart Benton—had secured funding for the expedition. Ten thousand copies were published the following year, to rave reviews. Included was the spectacular “Map Of An Exploring Expedition To The Rocky Mountains” measuring 52 x 30 inches, and stretching from the Missouri River west to the Pacific Ocean and from Los Angeles north to Mt. St. Helens.

However, much of the map was blank—to Frémont's credit. In a Notice to the Reader, he explained: "The map may have a meagre and skeleton appearance to the general eye, but is expected to be more valuable to science on that account, being wholly founded upon positive data and actual operations in the field." Indeed, the map is now considered a milestone, having set a new standard of cartographic accuracy for the American West.

The mapmaker was Charles Preuss, a trained surveyor and topographic artist from Prussia. He would accompany Frémont on three expeditions, making "continuous topographical sketches of the regions through which we passed, and which were never interrupted by any extremity of fatigue or privation" (Frémont's words). The large beautiful maps secured his reputation as a great cartographer.

Cartographer Charles Preuss, date unknown. Source (without attribution).

Laramie Plains up close

In the 30 years since publication of the Lewis and Clark map, techniques for representing relief hadn't changed all that much. Preuss also drew mountains using hachures, though in much greater detail. In the excerpt below (click to view), small narrow drainages are visible on mountains slopes, and low ridges and buttes dot the plains. Preuss varied hachures to show height and steepness. Lower ridges were drawn with shorter lines. Denser darker hachures indicated steeper slopes—for example Laramie Peak (top center of map) and, a short distance southeast, the canyon where the Laramie River crosses the Black Hills (now the Laramie Mountains).

From the 1845 map by Frémont and Preuss. Stars mark points where longitude and latitude were determined. At triangles, they measured the sun's height at noon to estimate latitude.

However, if we continue our examination, we're soon confused. Is that low mountain range paralleling the Medicine Bows Jelm and Sheep Mountains? Doesn't look right. Nor does the ridge east of the Main Fork. Most puzzling is the “Right Hand Fork” which (supposedly) joins the Main Fork of the Laramie River before it enters the canyon. Our history buffs still haven't solved this mystery.

Errors at this scale aren't surprising. With the great expanse of unknown territory ahead, there was little time for finer details, and though Preuss' map was highly accurate in its time, it's a far cry from the "very interesting map” showing every hill and canyon, which would so excite a Boomerang reporter 50 years later ...

[More to come in Part II.]

This post is based on the first of two articles about mapping the Laramie Plains, my most recent contribution to the "Laramie History" column in the Laramie Boomerang.

Sunday, March 14, 2021

Tree-following: Let it Snow!!

 

Two days ago, I took a few photos of Flash and Spike, the trees I'm following this year. As you can see, there's nothing left of the little bit of snow that was on the ground a month ago. It's been dry, dry, much too dry!! My too-big-to-water yard is covered in native grasses adapted to xeric conditions: western wheatgrass, alkali sacaton, prairie saltgrass. Even they are struggling after several years of drought. But they're tough. One day, their normally vigorous selves will return.

I water the young trees whenever temps rise above 40º F, to encourage root growth. But there are no obvious changes above ground, it's too early. So I checked their twigs to identify them using buds and scars. Of course I already know what they are. This was a chance to examine features I usually ignore.

I pulled the Winter Tree Finder out of my stack of tree-finders. These are dichotomous keys at their best—simple and fun. One got me hooked on tree id 50 years ago. With the handy twig diagram and friendly descriptions, I was able to find the various buds and scars, and make my way through the key.


For Spike, I didn't get beyond p. 4: "Sometimes a conspicuous feature ... makes identification easier." There were just two candidates with conspicuous thorns, Honey Locust (nope) and Hawthorns (yes), p 21, where I stopped because: "Hawthorns are far too numerous to cover here."
Spike the Hawthorn, with conspicuous thorns and alternate lateral buds.

With Flash, I made good use of the key, moving smoothly through the dichotomous questions. Tree a conifer or not? NOT. Leaf scars alternate or opposite? OPPOSITE. This year's twig more or less than ¼ inch wide? LESS. Leaf scars narrow, inconspicuous, with 3 bundle scars? YES. Terminal bud egg- or cone-shaped? YES. "It is a MAPLE, go to p 48" where I landed amid many maples, none of which grow here (the book covers midwestern and eastern North America).

Unfortunately, the buds and scars of the slender twigs were hard to photograph even though the wind was just a gentle breeze. I didn't dare cut twigs to photograph inside ... these young trees look like they need every twig they have. Here is my best shot, in fact, my only decent one.

Flash the Maple.

I waited until this morning to post, as I was hoping the weather forecast was correct. It was close! Now the scene is very different. The snowfall is going to be "absolutely historic" according to the weather news. If that's the case, then I must be prehistoric! But it IS a lot of snow, and quite wet. The plants and I are happy 😊 



This is my contribution to the monthly gathering of tree-followers hosted by The Squirrelbasket. More news here. Join us!