Blogs from our Scientific Researchers

Carnegie Museum of Natural History is home to active research and vast scientific collections. Our scientific researchers regularly contribute to the blog at the museum.

March 21, 2022 by Erin Southerland

Facing Outward, Looking Ahead: Richard Serra’s “Carnegie” As Part Of An 125 Year Legacy Of Architecture and Outdoor Sculpture

by Albert D. Kollar and Mary Wilcop

On a sunny fall weekend last November 6th and 7th, a celebration honored the 125th Anniversary (1895 – 2020) of the founding of the Carnegie Library of Pittsburgh (1895) and the Carnegie Institute Extension, now Carnegie Museums of Pittsburgh, by philanthropist Andrew Carnegie (1835 – 1919)¹(fig. 1).

Sculpture of Andrew Carnegie in an ornate marble room. — Fig. 1: Andrew Carnegie, Music Hall Foyer

Although the event had been postponed for a year due to the COVID-19 pandemic, the 2021 “Crash the Carnegies” celebration was enjoyed by thousands of visitors. Inside the Oakland museums, families enjoyed artmaking, performance, and learning activities that paid homage to Carnegie Museums’ past 126 years. Fronting Forbes Avenue, the statues and art works that lend much to the understanding of all that’s presented inside, continued their silent vigil.

The Buildings

The long stretch of buildings along Forbes Avenue in the Oakland neighborhood of Pittsburgh is home to Carnegie Museum of Art, Carnegie Museum of Natural History, and Carnegie Music Hall. The entrance to the Carnegie Library of Pittsburgh, the furthest west section of the massive complex, faces the gateway to Schenley Park. The connected buildings that comprise this modern campus were constructed in three distinct phases (the first building in 1895, an extension in 1907, and the new Scaife wing in 1974)². A review of the history of the Carnegie Library and Institute buildings’ is available in the posts “CMP Travel Program and Section of Invertebrate Paleontology Promote the 125th Anniversary of the Carnegie Library of Pittsburgh With a Walking Tour” and “A Journey to France to Uncover the Mysteries of the Carnegie’s Grand Staircase.”

Close-up of a steel bar with the name Carnegie on it. — Fig. 2: View from inside the museum: a Carnegie Steel Company I-beam supporting the roof of the 1907 extension.

With 1895-era facades made of elegant light gray Berea sandstone mined from a quarry in Amherst, Ohio ², the Carnegie Library and Institute building proclaimed itself to Pittsburgh and the world at large as, in Andrew Carnegie’s own words, a “palace of culture.”³ The library was built, both financially and literally, by Carnegie Steel. Earlier, the company’s structural metal beams were used in Pittsburgh’s first skyscraper, the Carnegie Steel Building, a structure designed by Longfellow, Alden, and Harlow (Floyd 1993)⁵. The Carnegie Institute Extension (1907), undergirded by a steel support frame, used steel beams fabricated at the newly created United States Steel Corporation Homestead Works, formerly Carnegie Steel¹ (fig 2).

John Massey Rhind Bronze Statues

Historic black and white photo of a group of people in front of a statue of Michelangelo. — Fig. 3: Michelangelo Statue. Courtesy of Carnegie Library Archives.

With the completion of the Beaux-Arts style Carnegie Institute Extension, departments of music, art, literature, and science were established as distinct administrative divisions of Carnegie Institute and Library. These now lapsed distinctions are mirrored on the building’s exterior in the bronze sculptures collectively referred to as the Noble Quartet. Seated in classical Greek chairs made of Barre Granodiorite of Vermont² are four male figures. The statues of Shakespeare (literature) and Bach (music) sit atop granodiorite slabs on either side of the main granodiorite staircase to the Music Hall entrance. Just east of them, at the entrance to the art and natural history museums, are seated Michelangelo representing art (fig. 3) and Galileo representing science.

Classical style stone building on a cloudy day. — Fig. 4: *Noble Quartet Muses*

John Massey Rhind (1858 – 1936), a close friend of Andrew Carnegie, was commissioned by him to create these works along with four others that tower three stories above them from parapets on the edge of the building’s roof (fig. 4). Known as the Muses, these standing female figures represent allegorical spirits whose achievements equal those of their seated counterparts. The creation of eight largescale architectural figures to match the Classical style of the building was not an easy task. Statue models shaped in clay by the artist, were shipped from his New York studio to Italy to be cast in the lost-wax process, then returned for assembly and finishing⁶.

Sarah Scaife Gallery

In 1974, the footprint of the Oakland campus expanded once more with the opening of the Sarah Scaife Gallery. Designed by renowned New York City architect Edward Larrabee Barnes (1915-2004), with large spaces and high windows, the gallery exterior is in some ways a modern equivalent of the Beaux-Arts Carnegie Institute Extension³.

The new building was constructed in a more modernist style commensurate with the contemporary architectural styles at the time. Its interior is clad with Larvikite, a beautiful gray blue iridescent igneous rock from Larvik, Norway⁸. The exterior cladding is also Larvikite, but here the stone has a bronze iridescent color to create visual continuity between the radically different Beaux Art and modernist structures.

By 1974, after nearly a century of atmospheric soot and pollutants from the steel mills and other modes of industrial and residential coal use, the old light gray Berea sandstone of the 1907 building darkened to a deep brown. This intended cohesion no longer exists because the sandstone underwent a major cleaning in 1989⁹. Its original pale tone now stands in contrast to the naturally bronze-toned Larvikite.

**Richard Serra Carnegie Sculpture and COR-TEN Steel**

In contrast to the bronze sculptures used in the 1907 Carnegie Extension, sculptures made of modern alloys of steel and aluminum are incorporated into the exterior plazas of the 1974 Sarah Scaife Gallery. The largest of these works is the Richard Serra Carnegie sculpture, which was installed as public art for the 1985 Carnegie International and was selected in a tie for that exhibition’s first prize¹⁰.

Richard Serra's Carnegie sculpture with the Cathedral of Learning framed in the background. — Fig. 5: Serra sculpture at CMOA

The 40-foot tower, made of four panels of 2.5-inch-thick COR-TEN steel with acute edges and corners, emerges from the Larvikite surface of the entrance plaza. The sculpture commands great sight lines with its height and profile echoing that of the nearby Cathedral of Learning, the University of Pittsburgh’s 42-story Gothic Revival, Art Deco tower (fig.5).

Steel skyscraper in downtown Pittsburgh. — Fig. 6: US Steel Tower. Image credit: Derek Jensen (Tysto).

COR-TEN is a proprietary high-strength, low-carbon steel alloy introduced by U.S. Steel Corporation in 1933. It features prominently in the company’s Pittsburgh headquarters, the U.S. Steel Tower, built in 1971 (fig. 6)¹². The name COR-TEN is an amalgam that references the product’s most notable properties, corrosion resistance and high tensile strength. The steel’s exceptional resistance to atmospheric corrosion negates the need for painting. After production, in a process that occurs over several months, a surface patina develops as the steel is exposed to wet and dry weather cycles. In many applications COR-TEN surfaces turn a reddish orange, but colors can vary from orange to brown depending, in part, on atmospheric conditions. Very fine surface oxidation layers can also build to create a rainbow-like iridescence, known as structural color – the same process that lends colorful beauty to peacock feathers and butterfly wings.

By the mid-1960s, the unique properties of COR-TEN attracted the interest of artists, especially those producing outdoor sculptures. Beverly Pepper, a sculptor known for her large-scale metal works, was introduced to COR-TEN’s properties while working at the U.S. Steel factory in Conshohocken, Pennsylvania. In 1964 she was the first sculptor to explicitly use COR-TEN as a sculptural medium¹¹. Other artists soon followed, including Serra in the early 1970s. Although Serra was originally trained as a painter, he was already familiar with the working properties of steel. The artist’s father worked in steel mills and as a pipefitter. Later, Serra supported some of his schooling by working in steel mills¹⁴.

By the time Serra’s design was conceived in 1985, only one company, the Lukens Steel Company, which operated the world’s widest rolling mill in the southeastern Pennsylvania town of Coatesville, could produce the large plates required for the commission. After production the plates were shipped across the state to a Pittsburgh-Des Moines Corporation plant on Neville Island, just outside Pittsburgh, for assembly.

The Significance of Carnegie

In its sheer size and monolithic simplicity, Carnegie lends itself to many interpretations. Like the large institution it fronts, the sculpture can be experienced from walking around the outside and by standing within.

By the time of Carnegie’s installation, leaning metal plates were a feature of several of Serra’s public sculptures. For Carnegie, however, the plates were made both to lean and tilt diagonally, rather than being strictly vertical, a form Serra describes as “almost like a V or like lifting your arms up.”⁶ Implicitly, though perhaps unintentionally, this form and its materiality may speak to the original vision Andrew Carnegie expressed in an 1897 letter: “….not only our own country, but the civilized world will take note of the fact that our Dear Old Smoky Pittsburgh, no longer content to be celebrated only as one of the chief manufacturing centers[sic], has entered upon the path to higher things, and is before long […] also to be noted for her preeminence in the Arts and Sciences”¹⁶.

Symbolism. Alone in Carnegie

The bare steel, deliberately lacking any interior or exterior covering, stands prominently in the plaza asserting its own essentialness to the story of the museum.

Fig. 7: View looking up from the interior of *Carnegie*.

To enter the sculpture’s interior from its Forbes Avenue side, visitors slide through a tapered passage between two plates. Once inside, even on the brightest summer days, several minutes are needed to adjust one’s eyes to overwhelming darkness of the interior. Following the walls upwards leads to a glowing view of the sky, blue or gray, depending upon the weather, and undoubtedly occasionally rose pink for some moments at dawn and dusk. The effect is intentionally physically and visually destabilizing (fig 7).

Ornate stone staircase — Fig. 8. Carnegie Grand Staircase

Some visitors experience entering the tower-like structure as a representation of a steel mill’s blast furnace. In this sense, the design functions as an extension of the John White Alexander Crowning of Labor murals in the Grand Staircase, which depict workers making steel in the first floor murals and, as the smoke rises to the second floor, reveal female spirits bringing the fruits of labor to a knight in steel armor who resembles Andrew Carnegie¹⁷ (fig. 8).

Serra often hesitated to assign a single meaning to his sculptures, preferring their interpretation remain broad and therefore boundless. Still, in an interview with Art Historian Vicky Clark during the work’s installation, the artist struggled to completely separate the sculpture from its implicit connections to the museum and Pittsburgh. “There’s something about steelworkers and the tradition of steelworkers that means that they have a basic respect for how something is built. It becomes a metaphor for what the industry of the town has produced.”⁶

Sculptures and Thought in the 21^st Century

While John Massey Rhind’s Noble Quartet functions mainly as an embellishment to the building, with a specific interpretation dictated by Carnegie himself, the situating of Carnegie in the plaza speaks to the extent to which the function of art and architecture, near the end of the 20^th century, had fundamentally changed. Rhind’s Quartet were positioned to sit along the sides of the Carnegie Institute’s original entryways, out of the path of visitors. Carnegie, in contrast, stands imposingly in front of the Scaife extension entrance, almost requiring entering patrons and passersby to engage with it.

Sculptures of the modern era, particularly those of architectural scale, create environments for individuals to think and reflect, without necessarily a prescribed end in mind. A viewer’s interaction with an artwork like Carnegie can feel obtuse; its faceless abstraction refuses to tell us what it is or how we should feel about it. This ambiguity, for Serra, however, is essential, because it means that “the piece has the potential to engage people with various meanings they might have.”⁶ Like the Quartet, Carnegie, speaks to the outside world about what we might find within. That is, that art, and the museum itself, serve as a site for contemplation and reflection—and not only about art.

Albert D. Kollar is the Collection Manager in the Section of Invertebrate Paleontology at Carnegie Museum of Natural History. Mary Wilcop is Associate Objects Conservator at Carnegie Museum of Art.

References

¹Kollar, A.D. 2021. The Carnegie Library of Pittsburgh (1895) and Carnegie Institute Extension (1907): The Story of the Carnegie Building Stones and Architectural Design presented for the 125^th “Crash the Carnegie” Celebration held in north wing of the Carnegie Library of Pittsburgh.

²Kollar, A.D., M. Feeley, A. Joyce Jr., R. Fedosick, K. Hughes, and A. Costanzo. 2020. Carnegie Institute Extension Connemara Marble: Cross-Atlantic Connections Between Western Ireland and Gilded Age Architecture in Pittsburgh, Pennsylvania. ACM, 86: 207-253.

³Gangewere, R. 2011. Palace of Culture Andrew Carnegie’s Museum and Library of Pittsburgh. University of Pittsburgh Press, 332p.

⁴Kollar, A.D. and B. Tucker. 2020. CMP Travel Program and Section of Invertebrate Paleontology promotes the 125^th Anniversary of the Carnegie Library of Pittsburgh with an outdoor walking tour. https://carnegiemnh.org/125th-anniversary-carnegie-library-of-pittsburgh-outdoor-walking-tour/

⁵Floyd, M.H. 1994. Architecture After Richardson, Regionalism before Modernism – Longfellow, Alden, and Harlow in Boston and Pittsburgh. The University of Chicago Press, Chicago. 546 pp.

⁶ Clark, V. November 1985. “Richard Serra’s Carnegie, an unpublished interview.” http://vickyaclark.com/serra_interview.html

⁷Gangewere, R. 1992. What the Muses Hold. Carnegie Magazine, 13-17.

⁸Heldal, T., and G. B. Meyer & R. Dahl. 2015. Global stone heritage: Larvikite, Norway. 21-34. Geological Society, London, Special Publication, 407.

⁹Gangewere, R. 1990. Cleaning The Carnegie. Carnegie Magazine, 31 – 35.

¹⁰CARNEGIE Fall 2021. 125 Years: A History in Objects Continues.

¹¹Smithsonian Archives of American Art. July 1-2, 2009. Oral history interview with Beverly Pepper. Washington, DC: Smithsonian Institution. https://www.aaa.si.edu/download_pdf_transcript/ajax?record_id=edanmdm-AAADCD_oh_283468

¹²Jester 1995.

¹²USS Cor-Ten Steel. 1980. USS Cor-Ten High Strength Low-Alloy Steel.

¹³https://www.aaa.si.edu/download_pdf_transcript/ajax?record_id=edanmdm-AAADCD_oh_283468

¹⁴ https://news.artnet.com/art-world/beverly-pepper-marlborough-contemporary-1470469

¹⁵ Lidji, E. 1985. CARNEGIE, Richard Serra. Carnegie International Article.

¹⁶Wall, J. F. 1970. Andrew Carnegie. University of Pittsburgh Press. 1137p.

¹⁷Gangewere, R. personal communication.

St. Patrick and Our Fear and Fascination With Snakes

by Patrick McShea

Through the lens of natural history, the legend of a Fifth Century Christian Missionary driving the snakes of Ireland into the sea has no factual basis. Ireland was snake-less territory long before the man now known to the world as Saint Patrick arrived on the scene, a condition attributable to the massive glacial ice sheet that covered the island and surrounding territories beginning approximately 26,000 years ago. In the centuries since the ice melted, as the Irish landscape became hospitable to various plants and animals, the surrounding cold Atlantic waters prevented the migration of snakes from nearby lands.

Colorful stained glass window depicting St. Patrick. — “Saint Patrick (stained glass)” by jcbwalsh is marked with CC BY-NC 2.0.

If St. Patrick’s enduring reputation as a reptile wrangler can be best explained by reference to religious symbolism, his legendary feat remains a testament to the long-standing fear and fascination humans have for snakes. Proof of this two-fold regard can also be found in the myths that persist in places where encounters with snakes are commonplace.

Colorful stylized snake — 2022 logo for the St. Patrick’s Festival in Dublin, Ireland

In Pennsylvania, where 21 species of snakes are considered to be native, a considerable amount of misinformation about our legless neighbors has developed during the Commonwealth’s 235-year history. Most of myths can be easily addressed – hoop snakes, creatures capable of holding their tails in their mouths to roll down hills, simply do not exist; the source of the cucumber smell some people associate with copperheads might be a habitat odor created by the rot of decaying bark and other vegetation; and snakes are simply not physically equipped to dig their own extensive tunnel systems.

One particularly persistent myth involves interbreeding between timber rattlesnakes (Crotalus horridus), one of three venomous species found in Pennsylvania, and black rat snakes (Pantherophis alleghaniensis), a common species that frequently draws human attention because of its tree climbing abilities. Young black rat snakes have a banded pattern that has repeatedly led some human observers to speculate about rattlesnake ancestry.

Museum display of timber rattlesnakes. — In the display of Pennsylvania’s venomous snakes, a tiny button of a rattle is visible on the tail end of this nine-inch-long timber rattlesnake.

The Pennsylvania snake displays on the Daniel G. & Carole L. Kamin T. rex. Overlook are the perfect place to develop the type of memory image required identify a young black rat snake, and perhaps minimize the attendant anxiety of an unexpected future encounter.

Museum display of black rat snakes. — A display of Pennsylvania’s non-venomous snakes includes a juvenile black rat snake (right) next to a larger and darker adult.

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees blog about their unique experiences and knowledge gained from working at the museum.

Pittsburgh Launches Spring 2022 Lights Out Program to Protect Migratory Birds

Yellow, gray, and white bird on a hand outdoors. — Blackpoll Warbler

Carnegie Museum of Natural History’s BirdSafe Pittsburgh program announces the Spring 2022 Lights Out Pittsburgh campaign. Lights Out Pittsburgh, an endeavor launched in September 2021 by BNY Mellon, the Building Owners and Managers Association of Pittsburgh, Carnegie Museum of Natural History, the National Aviary, and Pittsburgh Downtown Partnership, encourages owners of businesses and homes to turn off lights during peak migration hours, reducing bird window collisions and disorientation caused by artificial light in the night sky. Lights Out Pittsburgh seeks to build on the momentum of its successful fall campaign that recruited 75 buildings to join the movement.

More than 100,000 birds pass over the Pittsburgh region each year during fall and spring migrations, and research indicates that window collisions and disorientation brought about by bright lights are leading causes of bird fatalities. Lights Out Pittsburgh invites partners to join a growing national community of businesses and residences by turning off as much internal and external building light as possible—particularly in upper floors and lobbies—during the hours between midnight and 6 a.m. from March 15 to May 31.

Close up of a pale brown bird with a black and white striped throat. — Hermit Thrush

“Bringing a Lights Out program to Pittsburgh last fall culminated a long-time professional goal,” said Jonathan Rice, Urban Bird Conservation Coordinator at Carnegie Museum of Natural History and manager of BirdSafe Pittsburgh. “Now it’s time to build on that. Eight years of research has shown us where birds collide in our city. This Lights Out program is the first step in making Pittsburgh a safer place for birds stopping over during migration, or who live here year-round.”

Lights Out Pittsburgh‘s Spring 2022 campaign will mitigate avian fatalities as migratory birds head to their summer destinations. BNY Mellon, Carnegie Mellon University, Carnegie Science Center, Eleven Stanwix, House Building, Law & Finance Building, Point Park University, Union Trust Building, United Steelworkers’ Building, 100 Ross, 20 Stanwix, 600 Waterfront, and other buildings have pledged to turn off unnecessary lighting from midnight to 6 a.m. Others can join by visiting birdsafepgh.org.

“I am proud that BNY Mellon initiated this movement in the city of Pittsburgh,” said Christina Bencho of BNY Mellon. “Each year it becomes increasingly important that we use our reach, market influence, and resources to support environmental, social, and governance (ESG) issues. As one of the largest building owners in the city, this is a topic we felt passionate about moving forward.”

Since 2014, BirdSafe Pittsburgh has coordinated volunteers to monitor key neighborhoods during migration periods, collecting data documenting bird fatalities and providing care to birds with injuries caused by window collisions. BirdSafe Pittsburgh will document the Lights Out initiative’s progress on reducing bird mortalities.

The collaborative effort to save birds on their migratory journeys continues to grow as businesses and residents join the pledge to turn off unnecessary lights from midnight to 6 a.m. during peak seasonal migration periods. All are welcome and encouraged to participate. For more information about the Pittsburgh area Lights Out initiative or volunteering for BirdSafe Pittsburgh, visit birdsafepgh.org.

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BNY Mellon is a global investments company dedicated to helping its clients manage and service their financial assets throughout the investment lifecycle. Whether providing financial services for institutions, corporations or individual investors, BNY Mellon delivers informed investment and wealth management and investment services in 35 countries. As of June 30, 2021, BNY Mellon had $45.0 trillion in assets under custody and/or administration, and $2.3 trillion in assets under management. BNY Mellon can act as a single point of contact for clients looking to create, trade, hold, manage, service, distribute or restructure investments. BNY Mellon is the corporate brand of The Bank of New York Mellon Corporation (NYSE: BK). Additional information is available on www.bnymellon.com. Follow us on Twitter @BNYMellon or visit our newsroom at www.bnymellon.com/newsroom for the latest company news.

About BOMA Pittsburgh – Since 1919, the Building Owners & Managers Association of Pittsburgh has been helping owners and managers of commercial real estate maintain safe, efficient properties in Western PA. We do this through state and local advocacy, fostering professional connections through networking events, organizing members to serve in the local community, and training the next generation of commercial real estate leaders. BOMA Pittsburgh is proudly Federated with BOMA International, and our members operate over 31 million square feet of commercial real estate.

Carnegie Museum of Natural History, one of the four Carnegie Museums of Pittsburgh, is among the top natural history museums in the country. It maintains, preserves, and interprets an extraordinary collection of millions of objects and scientific specimens used to broaden understanding of evolution, conservation, and biodiversity. Carnegie Museum of Natural History generates new scientific knowledge, advances science literacy, and inspires visitors of all ages to become passionate about science, nature, and world cultures. More information is available by calling 412.622.3131 or by visiting the website, https://carnegiemnh.org.

About the National Aviary – The one and only National Aviary celebrates 70 years of saving birds and protecting habitats in 2022. Located on Pittsburgh’s historic Northside since its founding in 1952, the National Aviary is home to 500 birds representing more than 150 diverse species from around the world, many of them threatened or endangered in the wild. The National Aviary’s large walk-through habitats create an intimate, up-close interaction between visitors and free-flying birds, including opportunities to hand-feed and to meet many species rarely found in zoos. Hours of operation are 10:00 a.m. – 5:00 p.m. daily except for Tuesdays. For tickets and more information visit aviary.org.

About the Pittsburgh Downtown Partnership The Pittsburgh Downtown Partnership (PDP) is a dynamic, nonprofit organization comprised of business and community leaders, property owners, civic organizations, foundations, and residents who provide energy, vision, and advocacy for Downtown Pittsburgh. Working collaboratively with its partners, the PDP strives to create a positive Downtown experience for residents, workers and visitors alike. The PDP’s strategic initiatives include clean and safe services, transportation, and economic development and advocacy. For more information, visit www.DowntownPittsburgh.com, follow us on Twitter at http://twitter.com/downtownpitt and “like” us on Facebook.

March 8, 2022 by Erin Southerland

Reptiles, and Amphibians, and Bones? Oh My!

by Anais Haftman

I am a fourth year biology student at Duquesne University who has had the pleasure to work in the Section of Amphibians and Reptiles since 2021. Most of my time working in the section has been dedicated to cleaning the bones of specimens in the collection to ensure proper long-term preservation. With over 7,000 osteology (skeletal) specimens in the section, bone cleaning can be a tedious task. With the help of the museum’s Conservator Gretchen Anderson, and Collection Manager of Amphibians and Reptiles Stevie Kennedy-Gold, the long process of conserving and improving the quality of the osteologic specimens has been a breeze.

Why is a clean osteology collection important?

Conservation of specimens (wet and dry) in research collections is of the of the utmost importance because each specimen is a time and place record of species occurrence that can be re-examined as necessary. Some specimens are notable for having informed past research, and all specimens are held in public trust for their potential to inform current and future research. Because our specimens are routinely loaned out to researchers for use in studies, we work to ensure that their work is not diminished by ensuring the highest quality specimens possible. As the quality of a specimen decreases, the quality of information received from it also decreases.

Close up of a turtle shell with the specimen number CM 114627 on it. — There’s no separating a turtle’s backbone from its shell, even for cleaning purposes. Photo by Stevie Kennedy-Gold.

What makes the osteology specimens unclean?

One of the most common culprits behind our need to clean bones are dermestid beetle larvae. But wait, why in the world would there be beetles in the bone boxes? Dermestid beetle larvae are commonly used to eat flesh and cartilage off specimens before they are added to the collection. During this process sometimes a larva or two wiggle themselves into small holes in the bones and are not seen when the bugs are cleaned off prior to storage. In these cases, we simply remove any long dead hitch-hiker larvae we find.

Sometimes natural oils and fats also remain on bones after the initial dermestid cleaning. In these cases, the cleaning process becomes more complicated. The most common circumstance that creates a need for cleaning, however, is the presence of inactive mold on specimens. Most of the time this issue can be easily solved by using a simple paint brush or Q-tip. But other times, particularly on large sturdy bones, I needed to put in a good amount of elbow grease!

How is the bone cleaning done?

Gretchen taught Stevie and I all we needed to know to properly clean bone specimens. The first step is always to visually inspect the specimen and record its condition. We make sure to write down its identifying collection number, what species it is, whether it’s a whole skeleton or only parts, if there were dermestid larvae still present on the specimen, and much more.

Person cleaning bones with a vacuum. — The author using the vacuum tube to clean bones. Photo by Stevie Kennedy-Gold.

Once the data collection on the initial quality is complete, the cleaning can begin. We initially use a Nilfisk HEPA vacuum tube (a device we named R2-D2) to clean any inactive mold from the bones. Wearing protective masks, we manually loosen the mold and push it into the vacuum using paint brushes. Once the mold is removed, we are able to inspect the bones for presence of larvae or secreted oils. If there are larvae present, we carefully remove them with tweezers and put them in our “bug box.” If there are oils present, a Q-tip is used to clean it off. For smaller bones, such as individual vertebrae, a soak in 70% ethanol is often part of the cleaning process.

Snake vertebrae in a container from above — The delicate ribs and vertebrae of a snake require a delicate cleaning touch. Photo by Stevie Kennedy-Gold.

Depending on the quality and size of the osteological specimen, it can take anywhere from fifteen minutes to an hour to clean completely. Overall, much of the work to preserve osteologic specimens happens behind the scenes. This vital work is an example of the never-ending important tasks performed by both staff and volunteers that make the museum an important resource for scientific research.

Anais Haftman is a biology student at Duquesne University and works in the Section of Amphibians and Reptiles at the museum. Museum staff, volunteers, and interns blog about their unique experiences and knowledge gained from working at the museum.

“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

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,¹was 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

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.

¹¹Kurak, 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.

Fall 2021 Lights Out Pittsburgh Overview

by Jon Rice

Why Lights Out Pittsburgh?

Over the past eight years, scientists from Powdermill Nature Reserve have conducted research in Downtown Pittsburgh, working with the generous help of the public to determine where and when birds collide with windows and other building surfaces. During this time, we have determined what building parameters make the structures deadlier to birds. Meanwhile, at Powdermill Nature Reserve, research on avian perception of glass has identified and tested products that can deter birds from colliding with windows. Outside of these research efforts, one major factor related to window collisions demands more attention – light pollution.

Pittsburgh skyline at night with lights on.

As birds migrate at night, using the moon and stars to navigate, they can become disoriented by light pollution coming from the ground surface below them. The source is often large cities, but urban sprawl and suburban areas can be just as detrimental. Disoriented birds are drawn out of the sky into these areas, often ending their migratory flight for the night, when otherwise they would continue flying. It’s at this stage, when migrating birds are close to the ground and moving among buildings, that a large percentage of window collisions occur.

Dark Sky Ordinances and Lights Out Pittsburgh

Many cities around the world have begun developing dark sky ordinances to reduce light pollution for multiple reasons, including public health, improved potential for astronomical observations, and wildlife conservation. The City of Pittsburgh created such an ordinance in August of 2021. At the same time, Carnegie Museum of Natural History was approached by the National Aviary at Pittsburgh and the Building Owners and Managers Association (BOMA) with a proposal to start a local Lights Out initiative. A program modeled after existing ones in Philadelphia and several Ohio cities was developed with the input and aid of BOMA, whose participation ensured representation for the owners and managers of some of the city’s largest buildings.

Pittsburgh skyline with lights off during Lights Out Pittsburgh.

Skyscrapers aren’t the only buildings participating in the program. Residential homes, apartment buildings, and other low-rise buildings are also encouraged to participate in the Lights Out initiative. To participate, all one must do is turn out unnecessary external lights from midnight to 6:00 a.m. between March 15 and May 31, then again between September 1 and November 15. These weeks-long intervals are the peak spring and fall avian migration periods.

Fall 2021 Lights Out Results

In the first week of our Fall 2021 Lights Out campaign, 18 buildings signed up. Five were residential homes in the area, and 13 were large commercial buildings in Downtown Pittsburgh, including Point Park University, BNY Mellon Center and Client Service Center, and several PNC Downtown properties. Over the next month an additional 35 participants joined. In total, 73 buildings began participating in the fall migration period, and we are hopeful participation will grow in the upcoming spring season from March 15 to May 31.

To learn more about how you can get involved or participate in Lights Out Pittsburgh visit our website birdsafepgh.org or email us at birdsafepgh@gmail.com.

Jon Rice is the Urban Bird Conservation Coordinator at Carnegie Museum of Natural History’s Powdermill Nature Reserve. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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**Richard Serra Carnegie Sculpture and COR-TEN Steel**

Sculptures and Thought in the 21^st Century