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Carnegie Museum of Natural History

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Benedum Hall of Geology

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“To Cross A Bridge”: Fern Hollow Bridge in Pittsburgh, A Geology Story

by Albert D. Kollar and Wendy T. Noe

In the early morning of January 28, 2022, Pittsburgh’s 52-year-old Fern Hollow Bridge collapsed into Fern Hollow Run of Frick Park. Thankfully, there were no fatalities. The event made local and national news1. On February 7, the National Transportation Board (NTSB) reported it could take 12 to 18 months for a final report to determine the cause of the collapse2. 

Fern Hollow Bridge

Geological map of the Fern Hollow Bridge and surrounding area.
Fig. 1

The now infamous bridge, which carried Forbes Avenue’s vehicle and pedestrian traffic between Squirrel Hill and Regent Square, crossed a Frick Park hollow at the 900-foot contour level from anchor points at the base of the sedimentary rock unit known as the Morgantown Sandstone (fig. 1, fig. 4b). The bridge, one of 446 bridges in the City of Pittsburgh,1 was a steel rigid frame, a design in which the superstructure and substructure are rigidly connected to act as a continuous unit. The structure included three spans, with a total length of 447 feet (48.7 meters). Its road surface was 160 feet above (48.7 meters) Fern Hollow Run, and the bridge operated with a weight limit of 26 tons2. 

To Cross a Bridge

Bridges are built to carry people, all manner of the materials we require, and the vehicles used to transport both, across obstacles that would otherwise disrupt the smooth and timely flow of traffic. In our modern world bridges are frequently constructed to cross other built structures. Think pedestrian bridges over roadways, or highway bridges over busy rail lines. Mostly, however, bridges cross geologically formed features such as rivers and the myriad forms of depressions carved into the landscape over time by flowing water. Whether we call them valleys, ravines, or hollows, our region’s familiar landscape features are evidence of the impact of erosion on what was once far more level terrain.

Pittsburgh, with 446 bridges within the city limits, has long been known as the City of Bridges. The title is appropriate because the tally far exceeds the number of bridges in Venice that cross the Italian city’s network of canals3. Bridges are so common in Pittsburgh that for many residents it’s a daily experience to both cross over and pass under a bridge.

In human history, one of the oldest existing bridges dating from antiquity is the single-arch stone bridge over the Meles River, built c. 850 BC in Izmir (formerly Smyrna) Turkey.4

In Pittsburgh, the first fixed river crossing structure was the Monongahela Bridge, which was built in 1818. The form of this landmark can be inferred from Russell Smith’s Old Monongahela Bridge, a painting in the Carnegie Museum of Art (CMOA) collection that depicts the bridge during its construction. This largely wooden bridge burned during the great Pittsburgh fire of 1845, destruction captured in another CMOA landscape painting, View of the Great Fire of Pittsburgh, by William C. Wall. In 1883 the award-winning Smithfield Street Bridge rose from the ashes at the site of the former bridge. The Pittsburgh History and Landmarks Foundation designated the Romanesque Pauli lenticular truss as an historic bridge in 1970, recognition reinforced in 1977, when it was also cited as a City of Pittsburgh Historic Structure. It’s therefore reasonable to hope that a new Fern Hollow Bridge may one day be cited as having an award-winning design like the Smithfield Street Bridge.

Pittsburgh Geology

Paleogeography map of Pennsylvania
Fig. 2

Understanding the origins of the landscape features in Pittsburgh that make hundreds of bridges a necessity requires background knowledge of two long and widely spaced periods of Earth’s geologic history. Conditions during the first period help explain why rock layers here appear (mainly in roadcuts) stacked in relatively flat layers. During the Pennsylvanian Period (319 million to 299 million years ago), what is now Pittsburgh was centered near the equator where the fluctuating levels of a tropical sea deposited lime mud that later hardened to limestone. In lush swamps that covered much of a broad sea edge coastal plain, tropical plants grew so dense that their remains were later transformed into coal deposits. Large rivers that flowed from the eroding ancestral Appalachian Highlands, hundreds of miles east of Pittsburgh, carried sand, silt, and mud to the coastal plain, forming sandstone, siltstone, and shale along the way5 (fig. 2). 

The lithified sediments formed strata that became the bedrock beneath the Pittsburgh area. Geologic forces have been changing the landscape ever since. First through formation of the Appalachian Mountains by the action of plate tectonics, c. 260 million to 250 million years ago, followed by 250 million years of erosion. The majestic Appalachians were reduced to a broad plateau in western Pennsylvania where rivers and creeks meandered across a gently rolling plain creating wide shallow valleys.

Before the Ice Age

Map showing the drainage pattern of Western Pennsylvania before the Ice Age.
Fig. 3

As global climate cooled after the warm Pliocene Epoch (5.3 to 2.6 million years ago), glaciers started to form in Arctic Canada. In Western Pennsylvania at the time the drainage patterns of the ancestral Three Rivers and their tributaries flowed north and northwest from southern West Virginia through the Pittsburgh area and eastern Ohio, eventually converging with the Erigan River in what is present day Lake Erie (fig. 3). The Erigan River, thought by geologists to have been ancestral to the St. Lawrence River, flowed to the Atlantic Ocean6. 

In Pittsburgh, Monongahela River sediments were laid down as terrace deposits (clay, silt, cobbles, and boulders), creating a relatively flat bottomland, a base for the major traffic arteries of the city’s East End (fig. 1)9. 

Fig. 4a: Nine Mile Run Seen from Calvary c. 1928, John Kane. Fig. 4b: modern image with old Monongahela River level and Frick Park rock units.
Fig. 4
Fig. 5a: Panther Hollow, Pittsburgh c. 1933-1934 John Kane. Fig. 5b: modern image of Prehistoric Monongahela River with Schenley Park rock units
Fig. 5

Kollar and Brezinski (2010) visualized the pre-Ice Age ancestral Monongahela River through a geologic lens using two paintings by John Kane, “Nine Mile Run Seen from Calvary,” c. 1928 (fig. 4a) and fig. 4b geology version and “Panther Hollow, Pittsburgh,” c. 1930 – 19349 (fig. 5a) and fig. 5b geology version.

Here Comes the Ice Age: The Pleistocene Epoch in Western Pennsylvania

It was during the Ice Age or Pleistocene Epoch (2.6 million to 11,700 years ago)7, when the erosional actions of water impacted Pittsburgh’s landscape.

Thick glacial ice sheets advanced into western Pennsylvania at least three times, starting with the earliest known advance, 700,000 years ago. The last glacial incursion occurred some 20,000 years ago, when the Laurentian Ice Sheet advanced to the N400, about 40 miles northwest of Pittsburgh, depositing terminal moraine sediments in southern Butler and Lawrence counties8. 

Fig. 6: Reconstruction of Lake Monongahela (blue) of the tri-state area with modern towns and state boundaries for reference.
Fig. 6

With each advance of the glaciers, ice dammed the northwest flowing rivers (fig. 3). Like a clogged bathtub, water levels rose, backing up into creeks, streams, and runs to an elevation of approximately 1,100 feet (335 meters)6 to form Lake Monongahela7. Fig. 6 indicates in blue the highest water level of Lake Monongahela, a level high enough to breach and subsequently erode channels over drainage divides. 

This erosion through existing divides changed the region’s drainage from northwest towards the ancestral Great Lakes, to southwest towards the Gulf of Mexico, with the present-day Ohio River as the primary channel7. 

An example of geology changing the course of history.   

Lake Monangahela, Oakland 20,000 years ago
Fig. 7
Fig. 8a: Turtle Creek Valley No. 1 c. 1930 John Kane. Fig. 8b: modern image with approximate level of glacial ice 20,000 years ago.
Fig. 8

Lake Monongahela was geographically extensive. It extended east to Latrobe, south to Clarksburg, WV, west to eastern Ohio, and north to Elwood City (fig. 6). All of Oakland, including the current locations of Carnegie Museums and the University of Pittsburgh campus were flooded (fig. 7)5. Even the George Westinghouse Memorial Bridge (1932) in East Pittsburgh standing 240 feet (73.1 meters) above Turtle Creek would have been covered by Lake Monongahela (fig. 8b). See John Kane’s landscape painting, Turtle Creek Valley No. 1, c. 1930 (fig. 8a)10.  

Geology of Fern Hollow

Fig. 9: Evolution of three rivers at downtown Pittsburgh from Early Pleistocene to the present.
Fig. 9

As the glaciers advanced into, and melted back from, northwestern Pennsylvania, the weight of the ice had impacts on the Earth’s crust in the northern latitudes of North America. The crust would compress with the advance of the ice, and then slowly rebound each time the ice sheets melted. As a result of these fluctuations and continued erosion, during the time period stretching from Early Pleistocene to the present, the landscape shifted from a gently rolling plain dissected by shallow, meandering stream valleys into broader, deeper valleys, deeper hollows, and ravines6 (fig. 9). 

In Frick Park, the strata exposed along the eastern flank of the ravine at the Fern Hollow Bridge, as shown in (fig.1, fig. 4b,) consists of sedimentary rocks from the Carmichaels Formation9. The current floor of Fern Hollow is Saltsburg Sandstone, a unit formed about 300 million years ago9. Sedimentary rocks are, by nature, more prone to erode than igneous and metamorphic rocks, which don’t occur in western Pennsylvania. Some estimates propose that it takes about a million years to erode approximately 164 feet (50 meters) of rock11 within the river valleys and hollows of this region. Assuming this estimate is valid, which might not be the case, it would have taken a million years for the valley of Fern Hollow Run, and that of nearby Nine Mile Run, to be eroded to their present elevations.

Summary

Every bridge crossing is a potential encounter with geology. This scientific discipline offers insight into the natural dynamics that shape landscapes through deposition of sediments, mountain building, and erosion, all factors that help account for the locations where our region’s hundreds of bridges were built as transportation necessities. 

 Albert D. Kollar is Collections Manager for the Section of Invertebrate Paleontology at the museum Kollar and Wendy T. Noe serve on the Board of Directors of Pittsburgh Geological Society. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

References

Brezinski, D. K. Fig. 7.

Harper, J. A. Figs. 1, 2, 3, 6, 9.

Kollar, A. D., and Brezinski, D. K. Figs. 4, 5, 8.

1New York Times, 28 January 2022.                                                                                                

2Guza, M. 2022. NTSB report: Pittsburgh’s Fern Hollow Bridge collapse started on Squirrel Hill side. Pittsburgh Tribune Review.                                                                                          

3Bramgati, A., et al. 2003. The Lagoon of Venice: Geological setting, evolution and land subsidence. Episodes, 26, 264-268.                                                                                   

4ASMOSIA XII INTERNATIONAL CONGRESS. 8 – 14 October,2018, Izmir, Turkey. 

5Brezinski, D. K. and A.D. Kollar. 2005. The Geology of Schenley Park: A Record of Climate and Sea Level Change 300 Million Years in the Making. PAlS Publication Number 1, 5 p. 

6Harper, J. A. 2016. The Geological Evolution of Pittsburgh’s Three Rivers. PAlS Publication 21, 5 p.                                                                                                                                            

7Harper, J. A. 2002. Lake Monongahela: Anatomy of an immense Ice Age Pond. Pennsylvania Geology, 32, p. 2-12.                                                                                                                

8Harper, J. A., and A. D. Kollar. Geology of a Former Pleistocene Bog in Bridgeville, Allegheny County, Pennsylvania. Pennsylvania Geology. In review.                                                 

9Brezinski, D.K. and A. D. Kollar. 2005. The Geology of Frick Park A 300 Million Years Record of Climate and Sea Level Change. PAlS Publication Number 3, 5 p.                                    

10Kollar, A.D.,and 10D.K. Brezinski. 2010. Geology, Landscapes and John Kane’s Landscape Paintings. PAlS Publication 10, 5.                                                                                                                              

11 Kurak, E., et al. 2021. INCISION OF THE YOUGHIOGHENY RIVER THROUGH THE LAUREL HIGHLANDS DETERMINED BY A NEW RIVER TERRACE STRATIGRAPHIC AGE MODEL, OHIOPYLE STATE PARK, SOUTHWESTERN PENNSYLVANIA. Eds. Shaulis, J., Pazzaglia, F., and Lindberg, S. Guidebook for the 85th ANNUAL FIELD CONFERENCE OF PENNSYLVANIA GEOLOGISTS October 7 — 9, 2021.  

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Carnegie Museum of Natural History Blog Citation Information

Blog author: Kollar, Albert D; Noe, Wendy T.
Publication date: February 23, 2022

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Climate Change Myth Busting at the Museum

by Dr. Bonnie McGill

If you’ve visited the museum recently you may have noticed some new orange labels throughout the exhibit halls. These are part of an innovative visitor experience titled, We Are Nature: A New Natural History. I helped write the label you’ll find in Benedum Hall of Geology next to the oil and coal specimens. Its six-word headline reads “Burning fossil fuels causes climate change”. 

Tweet includes a selfie photo of the author in front of the new label. The tweet reads “That’s right—the fossil fuels exhibit @CarnegieMNH now states ‘Burning FF causes climate change’! A small but mighty change. #climatechange #scicomm” My twitter handle is @BonnSci and the museum is @CarnegieMNH.
Screenshot of a tweet I sent in December. 

This is an important exhibit update. When looking at a big chunk of coal, it’s hard to not think about climate change. Fossil fuel combustion is the leading cause of climate change. For example, from 2010-2019, burning fossil fuels (coal, oil, natural gas) accounted for 81-91% of total human-caused CO2 emissions (IPCC AR6 WGI 2021 ch 5 p 6). Over that same time period the measured global average temperature was 1.6-2.2 oF (0.9-1.2 oC) warmer than the pre-industrial global average temperature. This increase cannot be explained by natural processes (such as changes in solar irradiance or volcanoes), which actually decreased the temperature by 0.2 oF (0.1oC), according to the Intergovernmental Panel on Climate Change (IPCC) (IPCC AR6 WGI 2021 ch 3 p4).

While the museum has understood the science of anthropogenic climate change for many years, adding these new labels explicitly linking fossil fuels to climate change has created opportunities for new discussion and questions about what scientists know and what they don’t know. To help address these questions, the CMNH Natural History Interpreters have been working with the Climate and Rural Systems Partnership (CRSP) to bolster their climate conversation skills and climate science knowledge. One tool we at CRSP have developed with our regional network of community partners is a climate change myth busting resource that breaks down some of the most commonly repeated myths about climate change. 

Let me show you how the climate change myth busting resource works. For example, here is one myth we hear a lot:

“The climate has always changed, therefore this is natural.”

The guide provides three types of information to address the myth:

1. The science bottom line

Yes, the climate has always changed. This time it’s different. It’s more rapid than past changes and it can only be explained by human activity. 

2. The science in more detail (not a script, simply background information)

Past climate changes were dominated by naturally occurring cyclical changes in the Earth’s orbit and axis. Volcanoes and asteroid impacts have also changed the chemistry of the atmosphere and, thus, Earth’s temperature in the past. These forces continue to have effects. Today natural forces contribute a -0.2 oF effect on modern day global warming, which cannot explain the warming observed today. Human activities contribute a net increase of 1.4-2.3 oF. This means humans are having a 7- to 11-fold greater impact on global temperature than non-human forces of nature.

Scientists have 99.999% certainty that current climate change is human-caused. As the IPCC says “its unequivocal”. One of the strongest lines of evidence comes from comparing observed (past) global average temperatures with projections from climate models for the same time period. Only the climate models that include heat-trapping gas emissions from human activities match the observed temperatures (see plot below). Climate models that include only natural forces of climate change do not match observed changes in global temperature. 

Line graph of degrees C -0.5 to 2.0 on the vertical axis vs. year 1850-2020 on the horizontal axis. The lines stay near zero until about 1960 when the black (observed temperature) and brown (simulated temperature driven by humans and natural factors) move upward to about 1.5 degrees in 2020. The green line (simulated natural factors only) stays near zero and does not match the observed line.
Change in global surface temperature (annual average) as observed (in black) and simulated using human & natural (brown) and only natural (green) factors (both 1850-2020). Source: Intergovernmental Panel on Climate Change (IPCC) Working Group 1 (WG1) Sixth Assessment Report (AR6) Summary for Policymakers. https://www.ipcc.ch/report/ar6/wg1/#SPM

Additionally, fossil fuels are the only source of carbon (representing millions of years of plant-stored carbon) large enough to explain the observed increase in atmospheric CO2. The carbon isotopes in the CO2 match the carbon isotopes of fossil fuels. 

3. Ideas for moving the conversation toward solutions

Recognize that the person engaging in conversation seems to agree that the climate IS changing–shared agreement is vitally important.

It’s true the Earth’s climate has always changed—our planet has had ice ages and Hothouse periods caused by natural changes in the Earth’s orbit and axis, changes in solar irradiance, and volcanoes. This time it’s different. Natural cycles, solar energy, and volcanoes alone are not enough to explain the increase in atmospheric CO2 concentrations and Earth’s temperature. Human emissions of greenhouse gases, primarily from the burning of fossil fuels, do explain the increase in CO2 and temperature.

Knowing it is human-caused means it can be human-solved! It is important that we’re on the same page about the cause of climate change, so that we can develop effective solutions. For example, you could say, “Perhaps you might be interested in learning more about climate solutions, many of which improve other conditions too like our health?” For solutions to talk about see Project Drawdown. Transitioning to renewable energy will benefit air and water quality and human health.

Climate change information added to galleries, and training staff on climate science and techniques for talking about it in friendly ways, are just a few examples of how the scientists, educators, and exhibitions team are working together at CMNH to explore Anthropocene topics like climate change. We want to engage museum visitors and work with our regional communities to have productive climate conversations, open discussions that are oriented toward climate solutions and a positive future. Because at the end of the day that is what really matters. 

May 2022 update: Here is the completed myth busting resource, “Breaking up with climate myths with climate fact flip cards.” 

We also recommend this resource from our partner the Climate Advocacy Lab for learning more about having relational climate conversations.

Bonnie McGill, Ph.D. is a science communication fellow for the Climate and Rural Systems Partnership and based in the Anthropocene Studies Section at Carnegie Museum of Natural History. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Carnegie Museum of Natural History Blog Citation Information

Blog author: McGill, Bonnie
Publication date: February 10, 2022

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Understanding Fossil Fuels through Carnegie Museums’ Exhibits

by Albert D. Kollar, Collection Manager, with assistance from Suzanne Mills, Collection Assistant, and Joann Wilson, Volunteer Section of Invertebrate Paleontology

The exhibits of Carnegie Museum of Natural History and Carnegie Museum of Art are ideal for a multidisciplinary study of fossil fuels in Pennsylvania and beyond. Such a study must properly begin with some historical background about the landmark Oakland building that houses both museums, as well as some background information about fossil fuels.

When the Carnegie Library of Pittsburgh opened in 1895, the architects, Longfellow, Alden, and Harlow incorporated roof skylights for maximum daytime lighting in the Italian Renaissance designed building1. Nighttime activities were illuminated by interior gas lighting fixtures, possibly supplied by the Murrysville gas field, which began production in 1878.  With the opening of the Carnegie Institute Extension in 1907, the Bellefield Boiler Plant was built in Junction Hollow to supply in-house steam heat and electricity from bituminous coal1. From the 1970’s, coal and natural gas had been used to heat the boilers that supply heat to the Oakland Campus, Phipps, the University of Pittsburgh and the Oakland hospitals.  In 2009 coal was eliminated as a fuel source.  Electricity on the other hand, is supplied through Talen Energy from multiple sources (coal, gas, and renewal energy sources). For the future, Carnegie Museums of Pittsburgh plans to receive its electricity from renewable solar energy via Talen Energy2.

What are Fossil Fuels?

Coal, oil, and natural gas (methane), known collectively as fossil fuels, are sources of energy derived from the remains of ancient life forms that usually  are found preserved in coal rock, black shale, and sandstone.

Exhibit called "What's a Fossil Fuel?" Fossil fuels on display are labeled clockwise from the top as follows: peat, bituminous coal, anthracite coal, sub-bituminous coal, oil glass tubes, lignite.
Figure 1.

Coal is a rock. The coalification process starts from a thick accumulation of plant material in reducing environments where the organic matter does not decay completely. This deposit of plant residue that thrives in freshwater swamps at high latitudes forms peat, an early stage or rank in the development of coal. With the burial of peat over geologic time and a low temperature form of metamorphism produces a progression of the maturity or “rank” of the organic deposits that form the coal ranks of lignite, sub-bituminous, bituminous, and anthracite)3 (Fig. 1). The Pennsylvanian Period was named for the rocks and coals of southwestern Pennsylvania that formed more than 300 million years ago.

Oil and natural gas, collectively known as hydrocarbons, were forming in the Devonian rocks of Pennsylvania between 360 and 390 million years ago. These hydrocarbon deposits or kerogens are made of millions of generations of marine plankton and animal remains that accumulated in a restricted anoxia ocean basin that extended from southern New York, through western Pennsylvania, northern West Virginia to eastern Kentucky4. The thick layers of sediment formed black shales or mud rocks such as the Marcellus Shale. Black shales are rich in oil and gas and are called source rocks. Sandstones such as the Oriskany Sandstone that is older than the Marcellus Shale is a reservoir rock. An amorphous mass of organic matter or kerogen undergo complex geochemical reshuffling of the hydrocarbon molecules first with burial then by thermal “cracking” as heat and pressure through the geologic process of metamorphism over millions of years transform kerogen into modern day fossil fuels4.

Fossil Fuels in Modern Society

As commodities converted to fuels for our modern world, these resources account for 80% of today’s energy consumption in the United States5. All three fossil fuels, in furnaces of vastly different design, have been used to directly heat homes, schools, workplaces, and other structures. In power plants, all three have been used for generating electricity for lighting, charging mobile phones, and powering computers, home appliances, and all manner of industrial machines. In the United States, , coal became the country’s primary energy source in the late 1880s, displacing the forest-destroying practice of burning wood. It ceded the top spot to petroleum in 1950 but enjoyed a late-20th-century renaissance as the primary fuel for power plants5. Coal now generates approximately 11% of our country’s supply down from 48% just 20 years ago. Natural gas is currently used to generate approximately 35% of US electricity supplanting the use of coal6. While petroleum is less than1%6.

Transportation accounts for approximately 37% of total energy consumption. Coal played a historic role in powering railroads, and both compressed natural gas and batteries (charged with electricity generated from various sources) are of growing importance, however, refined oil products currently power 91% of the transportation sector6.

Newspaper clipping from The Rodnen & Otamatea Times dated Wednesday, August 14, 1912. The story shown is as follows: Science Notes and News. Coal Consumption Affecting Climate. The furnaces of the world are now burning about 2,000,000,000 tons of coal a year. When this is burned, uniting with oxygen, it adds about 7,000,000,000 tons of carbon dioxide to the atmosphere yearly. This tends to make the air a more effective blanket for the earth and to raise its temperature. The effect may be considerable in a few centuries.
Figure 2.

In the early 20th century, scientists warned about how the burning of coal could create global warming in future centuries by raising the level of carbon dioxide, a greenhouse or heat-holding, gas, in the atmosphere. (Fig. 2 ). It took less than a century for evidence to mount of climate change associated with the burning of fossil fuels, the clearing of forests associated with industrial scale livestock production, and from waste management and other routine processes of modern life. In recent decades headlines have routinely proclaimed the risks of a warming planet, including damage to terrestrial ecosystems, the oceans, and a rise in sea level7.

Fossil Fuels and Museum Geology Displays

When architects Frank E. Alden and Alfred B. Harlow designed the Carnegie Institute Extension (1907), they incorporated Andrew Carnegie’s vision to create an introduction hall to the museum named Physics, Geology and Mineralogy8. This hall (the forerunner to Benedum Hall of Geology) was intended to introduce Pittsburghers to the regional natural history subjects of geology, paleontology, and economic geology (fossil fuels)9.

Exhibit in Benedum Hall of Geology with fake trees in the foreground and a swamp diorama in the background.
Figure 3.

In the 1940s, the 300-million-year-old Pennsylvanian age coal forest diorama was installed in a corner space of what is now part of the Benedum Hall of Geology (Fig. 3). Because coal converted to coke is a vital ingredient in steel production, this three-dimensional depiction of the conditions under which Pittsburgh’s economically important coal deposits formed was (and remains) an important public asset.

Exhibit labeled Pennsylvanian Marine Life. Below the sign is a diorama designed to look like an aquarium.
Figure 4.

In 1965, as part of an overall plan to bring more of the natural history museum’s fossil collection to the public, Paleozoic Hall opened with funding from the Richard King Mellon Foundation10. This exhibition featured nine dioramas that recreate the ancient environments through 290 million years of Earth history. Sadly, only one of the nine units remains on display, the diorama depicting the Pennsylvanian age marine seaway (Fig. 4 ), in the Benedum Hall of Geology.

Since the Benedum Hall of Geology opened to the public in 1988 the exhibition has featured an economic geology component with displays explaining differences between coal ranks Lignite coal to anthracite coal, and a variety of Pennsylvania’s crude oils and lubricants processed from the historic well Edwin Drake drilled in Titusville in 1859 (Fig. 1 )11.

Benedum Hall of Geology strata wall. Shows different colors of rock stratigraphy from left to right: tan, blue-grey, maroon, beige, dark gray, olive green.
Figure 5.

Today, the Hall’s “strata wall,” a towering depiction of some of the rock layers found thousands of feet below western Pennsylvania, is in my opinion, an under-utilized display in terms of conveying information about fossil fuels. Although the wall is not currently documented with any geologic information, minor changes might allow visitors to use the lens of rock strata  to better understand historical events such as the Drake Well, and economically important geologic reservoirs such as the Marcellus Shale (the second largest gas deposit in the United States), the natural gas storage reservoir of the Oriskany Sandstone, and the gas and liquid condensate (ethane) extracted from the Utica Formation (Ordovician Age) for making plastic products at the Shell Cracker Plant in Beaver County, PA (Fig. 5 ).

Exhibit case labeled Holzmaden. A blue arrow points to a crinoid fossil.
Figure 6.

Elsewhere in the museum, visitors can learn more about the topic of fossil fuels at several other locations. At the Holzmaden fossil exhibit in Dinosaurs in Their Time, there is a large fossil crinoid preserved in a dark gray limestone of Jurassic age, that represents a  reservoir of crude oil in Germany (Fig. 6). At the mini diorama of the La Brea tar pits, oil seeps from natural fractures from an approximately six-million-year-old rock of Miocene age,  to the unconsolidated surface sediment in what is now part of the City of Los Angeles (Fig. 7).

La Brea tar pits diorama. A vulture sits on a tree above the tar pits.
Figure 7.

Looking for Fossil Fuel Evidence in Art

In 2018, I reviewed 58 landscape paintings and the John White Alexander wall murals on the first and second floors of the Grand Staircase within Carnegie Museum of Art (CMOA) galleries to look for artistic documentation of what I interpreted to be causes for climate change based on the science. I found many examples based on the use of coal as a fossil fuel for power and coking in steel mills and the natural formation of bio-methane as portrayed in ecosystem landscapes of  the industrial age of the middle 19th and early 20th century12.

Collage of coal landscapes. Clockwise from top right: Waterloo Bridge, London, Claude Monet c. 1903; The Great Bridge, Rouen (Le Grand Pont, Rouen), Camille Pissarro, c. 1896; Pittsburgh Fifty Years Ago from the Salt Works on Saw Mill Run, Russell Smith, c. 1884; The Crowning of Labor Murals, John White Alexander, c. 1905 - 1908; The Coal Carrier, David Gilmore Blyth, c. 1854 - 1858
Figure 8.

Collage of five illustrations of steel mills
Figure 9.

Searching for the CMOA landscapes paintings takes a little patience, but the visitor is rewarded by taking a new look at some of the art museum’s classic paintings (Fig. 8 and 9).

Three historic landmark signs. On left: First Mining of Pittsburgh Coal. This State's bituminous coal industry was born about 1760 on Coal Hill, now Mt. Washington. Here the Pittsburgh coal bed was mined to supply Fort Pitt. This was eventually to be judged the most valuable individual mineral deposit in the U.S. Sign on the top right: Drake Well Park. On this site Col. Edwin Drake struck oil Aug. 27, 1859; the birth of the petroleum industry. Sign on the bottom right: Murrysville Gas Well: First gas well in county and one of the world's most productive. Drilled, 1878. Caught fire in 1881, burning for years with tremendous roar and brilliance. Later was controlled and piped to Pittsburgh. Site lies 500 yards S.E. near railroad.
Figure 10.

Within day trip visiting distance of Carnegie Museums are historic plaques highlighting the discovery of coal on Mount Washington, natural gas in Murrysville, and oil in Titusville, Pennsylvania. (Fig. 10). At all three stops you’ll have a better understanding of the significance if you begin your investigation of fossil fuels at Carnegie Museums.

Albert D. Kollar is the Collection Manager for the Section of Invertebrate Paleontology. Suzanne Mills is the Collection Assistant and Joann Wilson is a volunteer Section of Invertebrate Paleontology. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

References

  1. Kollar, A.D. 2020. CMP Travel Program and Section of Invertebrate Paleontology promotes the 125th Anniversary of the Carnegie Library of Pittsburgh with an outdoor walking tour. https://carnegiemnh.org/125th-anniversary-carnegie-library-of-pittsburgh-outdoor-walking-tour/
  2. Personal communications Anthony J. Young, Vice President (FP&O) Carnegie Museums of Pittsburgh.
  3. Brezinski, D. K. and C K. Brezinski. 2014. Geology of Pennsylvania’s Coal. PAlS Publication Number 18.
  4. Geology of the Marcellus Shale. 2011. Brezinski, D.K., D. A. Billman, J.A. Harper, and A.D. Kollar. PAlS Publication 11.
  5. https://www.bloomberg.com/news/articles/2021-05-03/coal-consumption-in-the-u-s-declines-as-natural-gas-solar-wind-energy-rise
  6. United States Energy Agency (EIA) 2019.
  7. Bill Gates. 2021. How to Avoid A Climate Disaster.
  8. Kollar et al. 2020. Carnegie Institute Extension Connemara Marble: Cross-Atlantic Connections Between Western Ireland and Gilded Age Architecture in Pittsburgh, Pennsylvania. ACM, 86, 207-253.
  9. Dawson, M. R. 1988. Benedum Hall of Geology. Carnegie Magazine, 12-18.
  10. Eller, E. R. 1965. Paleozoic Hall. Carnegie Magazine, 255-338.
  11. Harper and Dawson 1992. Benedum Hall-A Celebration of Geology. Pennsylvania Geology, 23, 12-15.
  12. Kollar et al. 2018. Geology of the Landscape Paintings at the Carnegie Museum of Art, a Reflection of the “Anthropocene” 1860-2017. Geological Society of America, Abstracts with Programs, v. 49, 243.

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Carnegie Museum of Natural History Blog Citation Information

Blog author: Kollar, Albert
Publication date: May 5, 2021

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Behind the Scenes with the Baron de Bayet and L. W. Stilwell Collection Part 3:  The Wild West Formed Million of Years Ago

New to this series? Read Part 1 and Part 2.

photo of Badlands National Park
Figure 1:  Badlands National Park today, National Park Service photo, 2014.   This view of the Badlands topography illustrates the erosion that took place over the last 2 million years.

The Lakota called the Badlands “Mako Sica” or “land bad.” The early French-Canadian trappers referred to it as “les mauvais terres pour traverse” or “bad lands to travel through.”  Seventy-five million years ago, this area was a lush underwater seaway filled with creatures such as mosasaurs, plesiosaurs, diving birds, fish, baculites, and ammonites (Figure 2).

Figure 2: Taxa that swam in the Western Interior Seaway from Dinosaurs in Their Time exhibit at Carnegie Museum of Natural History.  Photo by Patty Dineen.

The Stilwell fossils of Cretaceous age (Figure 3) were deposited in a black mud that accumulated on the sea floor from 82 to 70 million years ago (Figure 4).  The Pierre Shale is part of the extensive Western Interior Seaway of North America (Figure 5).  Museum visitors can view a changing geographic representation of the seaway on a wall-mounted flat screen monitor within the Dinosaurs in Their Time exhibit.  The seaway extended from the Gulf of Mexico, Florida, and southern Gulf Coast, north through Texas, Kansas, Colorado, Wyoming, Montana, the Dakotas, and the Canadian Provinces of Alberta and Saskatchewan. This vast waterway terminated in the Artic region of Canada.  At the time of the Pierre Sea, the ice sheet-free greenhouse to hothouse paleoclimate was much warmer than it is today, creating the highest sea levels in earth’s history.  Sea level rises and falls were primarily controlled by the presence or melting of glaciers in the polar regions, the shifting of the continents, and the uplifting of proto-Rocky Mountains by plate tectonics.

Figure 3:  Western Interior Seaway fossils on display at Carnegie Museum’s Dinosaurs in Their Time exhibit.  Stilwell fossils are highlighted in blue.
Figure 4: Outcrop photo of Pierre shale.
Figure 5:  Western Interior Seaway approximately 75 million years ago. Red dot locates Deadwood, South Dakota today.

Fast forward to the Wild West of the 1890’s, and dealers such as Stilwell found and sold fossils to museums and private collectors.  Knowledge of Badlands fossils spread as far as Europe, and by 1889 Bayet wanted some for his own collection.

Next, in our final post of this series, we will delve into the Stilwell-Bayet correspondence in search of clues about how fossils were bought and sold over a century ago.

Joann Wilson is an Interpreter for the Department of Education and a volunteer with the Section of Invertebrate Paleontology. Albert Kollar is Collections Manager for the Section of Invertebrate Paleontology. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Behind the Scenes with the Baron de Bayet and L. W. Stilwell Collection, Part 2:  The Wild West a Century Ago

black and white photo of Deadwood from a distance
Figure 1:  Deadwood, Dakota Territories 1879.   Image courtesy of the Deadwood Historic Preservation Commission, City of Deadwood Archives.
black and white photo of a Deadwood street
Figure 2:  Deadwood, Dakota Territories 1879.  Image Courtesy of Deadwood Historic Preservation Commission, City of Deadwood Archives.

Fancy yourself on the hottest day in summer in the hottest spot of such a place without water — without an animal and scarce an insect astir — without a single flower to speak pleasant things to you and you will have some idea of the utter loneliness of the Bad Lands.”   Thaddeus Culbertson, 1850

When Lucien Stilwell stepped off the stagecoach on September 25, 1879, he was not your typical visitor to Deadwood.  Photos of Stilwell in later years show a thin scholarly figure with glasses. In 1879, Deadwood, Dakota Territories was known for gold prospecting, gambling and lawlessness.  Just three years prior, Wild Bill Hickock had been shot in the back while playing poker here.  It would be a few more years until Seth Bullock, first sheriff of Deadwood, would begin to bring order to town.

As Stilwell stepped off the stagecoach, he was leaving a fifteen-year career in the grocery and grain business in Cairo, Illinois.  A yellow fever epidemic blanketing parts of the United Sates prompted him to uproot his life.  He arrived just one day before a fire destroyed over 300 buildings and displaced over 2000 people in Deadwood.   According to Michael Runge, City Archivist of Deadwood South Dakota, photos of Deadwood in 1879 (Figures 1 and 2), were taken just before the great fire.  If you look closely at Figure 2, you can see a law office, hardware store, liquor store, and city market.

Despite the great fire and the dangers of Deadwood, Lucien W. Stilwell found a job at a bank, brought his family to town and built a home.  Along the way, he became fascinated by the fossils in the surrounding Black Hills.   He began a careful study of the region and developed relationships with other fossil collectors.   Eventually, he turned his hobby into a side business.

photo of faculties fossil
Figures 3 & 4:  CM 33067 – Baculites collected by Stilwell.  Baculites, translated as “walking stick rock”, are an extinct group of straight cephalopods that swam the seas 75 to 80 million years.  “Sutures” or growth lines are formed when the animal adds new shell material as it grows.  Sutures assist paleontologists in the identification of the genus and species.

Prior to leaving the bank in 1890, Stilwell began selling Badland fossils and minerals.  In a correspondence to the Baron de Bayet of Brussels dated January 12, 1889, Stilwell said, “I tried to catch your meaning in your last letter.  As I understand it, you wanted one of every specie and variety of fossils I had, excepting the large and costly specimens of mammals.”    

In one letter to Bayet, Stilwell wrote, “I put in a number of baculites, all of which have some different interest.  One is to show fine sutures another to show iridescence to rare degree, another to show size, another to show form so differing as to be a specie of baculite by another name…”   Albert Kollar of the Section of Invertebrate Paleontology explained that in circumstances when the exact stratigraphic locality is questionable, having the original fossil labels as seen in Fig. 4 are critical to accurate fossil identification.  Stillwell was a capable researcher because of his grasp of the geology and paleontology of the Badlands region.  Figures 3 and 4 show a baculites sold by Stilwell to Bayet.  There are 100 Stilwell fossils in the 130,000 specimen Bayet collection.

The next post in this series will explore why dealers such as Lucien W. Stilwell, found so many fossils in the Badlands.

Many thanks to the generous assistance of Michael Runge, Archivist for the City of Deadwood, South Dakota.

Joann Wilson is an Interpreter for the Department of Education and a volunteer with the Section of Invertebrate Paleontology. Albert Kollar is Collections Manager for the Section of Invertebrate Paleontology. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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A Century Ago, a Donor Walked into the Carnegie Museum

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The Giant Eurypterid Trackway: A Great Fossil Discovery on Display in the Carnegie Museum of Natural History

Figure 1.

When museum patrons enter Carnegie Museum of Natural History’s Benedum Hall of Geology, they encounter a one-ton block of coarse sandstone with a series of bilateral footprints encased on the rock’s surface. Most visitors don’t know what type of creature made these footprints (Fig. 1) or realize that this fossil trackway represents one of the great fossil discoveries in the history of western Pennsylvania paleontology.

Figure 2. Illustration by Kay Hughes.

Last month, the cover of Pennsylvania Geology (Fig. 2) helped address both deficiencies. The magazine bears a colorful illustration by Kay Hughes of a 315 million-year-old scene: a large six-legged arthropod emerging from the water and dragging its tail onto a sand bar among fallen Lepidodendron logs. The intruder is a Giant Eurypterid, a creature known to science as Palmichnium kosinskiorum, and a member of an extinct family of arthropods informally called “sea scorpions” that are distant biological cousins.

Within the journal is a fuller explanation for the artistic interpretation of the creature behind the Benedum Hall trackway, an article I co-wrote with Kay Hughes and John Harper titled, Reflections on Palmichnium kosinskiorum-The Footprints of Pennsylvania’s Elusive Elk County Monster.

Fortuitous Discovery

Figure 3. Photograph of Elk County in situ trackway looking southward (Brezinski and Kollar 2016).

Figure 4. Trackway closeup showing tail drag on display in Benedum Hall of Geology (Brezinski and Kollar 2016)

Seventy-two years ago, in an Elk County section of the Allegheny National Forest, James Kosinski, a preparator in the Education Department of Carnegie Museum of Natural History, and his brother Michael were hunting deer in heavily wooded terrain. When Michael stumbled upon a large sandstone boulder bearing a pattern of unusual impressions, he informed James, who (Fig. 3) immediately recognized the impressions as the fossil tracks of an unknown animal (Fig. 4).

Later, when James described the discovery to Carnegie Museum’s Dr. E. Rudy Eller, Curator of the Section of Invertebrate Paleontology, and Dr. J. Leroy Kay, Curator of Vertebrate Paleontology, plans were made to remove a section of the boulder containing the best-preserved section of the trackway and transport the heavy block to the museum.

Exhibit History

Figure 5. Former Paleozoic Hall Silurian Period Marine Diorama with Eurypterids.

Upon arrival at the museum in 1948, the sandstone block was prepared for exhibition and placed near the museum’s Coal Forest exhibit in 1949. In 1965, the trackway was incorporated as a floor centerpiece in the newly open Paleozoic Hall which featured dioramas of characteristic life forms of that Era’s time periods (Cambrian, Ordovician, Silurian, Devonian, Pennsylvanian, and Permian) along with representative fossils from the museum collection. (Fig. 5) In 1998, when Paleozoic Hall was dismantled, the trackway was placed temporarily in the Invertebrate Paleontology lab. The trackway returned to public view in 2007 as part of Bizarre Beasts, a temporary exhibition in the R. P. Simmons Family Gallery about unusual life forms. When Bizarre Beasts closed, I worked with James Senior, Chair of the museum’s Exhibit Department, to place the trackway in the Benedum Hall of Geology entrance as an introduction to great fossil discoveries from western Pennsylvania.

The Research – Locality Data Supports Recent Theory

The fossil trackway was initially identified by Dr. Kay as a hopping reptile inhabiting a Pennsylvanian coal forest 300 million years ago. Although Dr. Eller, citing his own research, suggested the track was formed by a crawling eurypterid, it would take 35 more years for the fossil trackway to be studied by expert arthropod paleontologists from Europe.

The eventual designation of Palmichnium kosinskiorum as a holotype specimen (CM 34388), a category of first order scientific importance, dates to the fossil’s description as a eurypterid trackway in a 1983 research paper by Dr. Derek E. G., Briggs and Dr. W. D. J. Rolfe, titled, A giant arthropod trackway from the Lower Mississippian of Pennsylvania (Journal of Paleontology, 57, 377 – 390). In paleontology, when a non-scientist such as Michael Kosinski discovers a fossil of importance, paleontologists, in this case Derek Briggs and Ian Rolfe, name the new fossil species after the founder, hence P. kosinskiorum.

For years, paleontologists in the Section of Invertebrate Paleontology assumed the scientific conclusions of Briggs and Rolfe (1983) about the eurypterid trackway were beyond dispute. This situation changed in 2009, when Yale University Professor Adolph Seilacher, a world-renowned expert on fossil trackways visited the museum. While Briggs and Rolfe concluded the trackway formed in a marine sandstone, Seilacher explained to me that the trackway was likely formed in an eolian or wind-blown sand environment. He also recommended that someone investigate the rocks at the fossil location in Elk County to substantiate his hypothesis.

Figure 6. D.K. Brezinski at trackway. 

Later that year, when I accompanied David K. Brezinski, Associate Curator Adjunct, Section of Invertebrate Paleontology, to re-locate and re-examine the sandstone boulder with the remaining tracks, we discovered the original geologic and deposition conclusion by Briggs and Rolfe (1983) was incorrect (Fig. 6). In 2011, we reported these new findings at the Northeastern Sectional Meeting of the Geological Society of America in Pittsburgh.  After the meeting, we continued our research and eventually published our conclusion that the geologic age of the trackway was Early Pennsylvanian age and the embedded footprints represented a fluvial sand bar environment of deposition.(Reevaluation of the Age and Provenance of the Giant Palmichnium Kosinskiorum Eurypterid Trackway, from Elk County, Pennsylvania, Brezinski and Kollar (2016),  Annals of Carnegie Museum 84, 39 – 45,)

School Groups and Museum Interpreters

Based upon repeated anecdotal reports from the Interpreters who guide tour groups through the museum’s exhibit halls, the eurypterid trackway is one of the most celebrated education stops for elementary school students. According to Interpreter Patty Dineen, the appealing factors of the trackway include the size and possible scariness of the creature who made the tracks, the fact the track-maker lived long before the dinosaurs, the fossil’s local origin, and the sheer amount for information that can be gathered from the ancient preserved tracks.

Figure 7. Interpreter field trip.

As part of an effort to better inform school groups about the eurypterid trackway, in 2017 Patty Dineen and Joann Wilson, co-coordinators and instructors for the museum’s Natural History Interpreters, arranged for six Interpreters to participate in a PAlS geology fall field trip to the fossil site in Elk County. (Fig. 7) An important by-product of field excursion was the creation of an instructional video that explains how museum scientists conduct research.

“Treasures of the Carnegie” Planning for a better Trackway Experience

Now that an illustration exists (Fig. 1) of the eurypterid that shaped the trackway walking out of the 315 million-year-old Olean River onto a sand bar, it might be time to consider how to best devise an improved visual and virtual tour experience for the Carnegie patrons and school groups.

Albert D. Kollar is Collections Manager for the Section of Invertebrate Paleontology at Carnegie Museum of Natural History. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.