BRUNSWICK, GA.- This patch of coastal wetland between highway and marsh, just behind downtown Brunswick, Georgia, is a kind of pilgrimage site — though no sign points to it.

Look for a small park along U.S. 17, with a pavilion and a pier from which people fish and trap crabs. Across the channel, the Marshes of Glynn stretch flat to the horizon.

But the object of interest — to some art historians and aficionados — sits just outside the park, where the spartina cordgrass takes over. Three rocklike forms nestle in the vegetation. They are weathered and easy to miss.

Here is a major work of American outdoor sculpture, hiding in plain sight. What look from afar like a random trio of rocks are in fact constructions of concrete topped with tabby, a historic material in this region formed from oyster shells, sand and water.

The “Marsh Ruins,” as they are called, are arguably the masterwork of painter and sculptor Beverly Buchanan. She built them in 1981, her own intervention in a charged landscape. The work is partly an homage to Igbo Landing, a fundamental story of Black freedom-seeking that unfolded at the other end of these marshes. It also deals a gnomic retort to “Marshes of Glynn,” a 19th-century poem steeped in antebellum nostalgia.

For four decades, the sculpture has sat unmarked and unknown, cracking and sinking into the marsh — just as the artist intended.

Buchanan, who died in 2015, grew up in Orangeburg, South Carolina, and emerged as an artist in New York before returning to the South in 1977, first to Macon, Georgia. There, she entered a period in which she placed works in the landscape. She built the “Marsh Ruins” in two sweltering days, with a local contractor, spending money from a Guggenheim fellowship.

She had obtained necessary permits but made no arrangements for the sculpture’s future. She would return from time to time to photograph or just contemplate what some believe was the work she most cherished.

One afternoon last May, I checked on the “Marsh Ruins,” having first visited them in 2018. Treading carefully on the soggy ground, I pushed through the dense cordgrass to inspect them. Fallen sections of tabby revealed the concrete substrate traversed by deep fissures. Their outer treatment, a copperish acrylic pigment, has long faded.

These need attention, I thought. And then caught myself: Or do they?

The “Marsh Ruins” present a paradox. They are recognized as a crucial work, amid a strong, albeit posthumous, renewal of interest in Buchanan. Her first thorough survey, which opened in 2016 at the Brooklyn Museum, organized by artist Park McArthur and curator Jennifer Burris, showed them in a video projected at large scale. That same year, art historian Andy Campbell examined them in an article. In 2021, art historian Amelia Groom devoted a book, “Marsh Ruins,” to the work.

On the other hand, they are slowly vanishing, their decay built into their premise. Buchanan called them “ruins,” after all. And while her other large-scale works of this period have caretakers — they sit on museum grounds, a college campus, a station plaza — she entrusted the “Marsh Ruins” only to the elements and time.

What should be done when a work is major partly because the artist invited its decay? Perhaps the “Marsh Ruins" challenge us to rethink the possibilities of conservation itself.

Buchanan trained as a scientist. She came to New York City for graduate studies, earning master’s degrees in parasitology and public health from Columbia University in the late 1960s, then worked as a health educator in the Bronx and New Jersey. But she also made and began showing abstract paintings, encouraged by Norman Lewis and Romare Bearden.

Her turn to sculpture began in New York. She used found bricks as molds for casting concrete and pulverized rocks to make pigments. She called the works “frustulas,” from a Latin word meaning fragments. She was fascinated by decay, regeneration and how, as she wrote in 1978, “piles of rubble can be pulled together to form new systems.”

She showed a “Wall Column” made of four cast cement sections in “Dialectics of Isolation: An Exhibition of Third World Women Artists of the United States” at A.I.R. Gallery — a landmark 1980 show that challenged prevailing conceptions of feminist art. Artists Ana Mendieta, who helped organize the show, and Howardena Pindell, whom it also featured, were among her friends.

By then, however, she had resettled in small-town Georgia — first Macon, then Athens — beginning a fade from view in the New York scene that was later compounded by ill health. But the South held her heart and concerns, and in Georgia, her sculpture added scales, materials and methods, in tune with the land and its stories.

Tabby, for instance, carried a deep charge. The material is closely associated with local Black survival practices during and after enslavement. Coastal Gullah-Geechee communities often used it to build dwellings and to mark graves.

And while her large land sculptures are known, she made uncountable other pieces that she placed in locations known only to her, rarely documenting them. She might add a tabby brick to a graveyard, place an ephemeral rock arrangement by the roadside, immerse a concrete piece in the Ocmulgee River to sink or a wood one to drift away. She kept materials to these ends in her yellow VW Beetle.

Buchanan’s last official outdoor sculpture, “Blue Station Stones,” was a public art project for a Miami-Dade Transit station, in 1986. She then turned principally to making “shack sculptures” — wood miniatures of rural shacks, stylized and painted lively colors or plain like architectural models. She added drawings, photographs and annotations, a la Zora Neale Hurston, about the Georgia dwellings and the people who inspired them.

For years, her reputation was reduced to these works. “In short, Ms. Buchanan makes sculptures of shacks,” read one 1994 review, comparing her to a folk artist. Elusive to begin with, her land pieces were mostly forgotten until the Brooklyn Museum show flagged off the rediscovery of her oeuvre.

Buchanan now features in important thematic exhibitions like “The Dirty South” in 2021 at the Virginia Museum of Fine Arts, or “Groundswell: Women of Land Art,” at the Nasher Sculpture Center in Dallas, which will open in September.

For that show’s curator, Leigh Arnold, Buchanan’s ambivalence to permanence and authorship helps to expand our understanding of land art as a category. “I think she thought of these environmental or private works as things that belonged to the world as a whole,” Arnold said. “She opened a window to histories rather than to herself.”

When McArthur and Burris were filming the “Marsh Ruins,” they fielded warnings from the men crabbing on the pier. “They said, you should watch out for the ghosts,” Burris said. “We said, what ghosts? And they told us the story.”

In 1803, a boat loaded in Savannah, Georgia, a group of captives who survived the Middle Passage — many Igbo — to deliver to plantations in St. Simons and Sapelo Island. In a creek on St. Simons, some men overpowered the crew and escaped in their shackles.

That part is documented. Much else about Igbo Landing is mythologized: The men walk into the ocean with dignity; they magically take flight. But the story has attracted artists: Carrie Mae Weems, for instance, photographed the purported site in 1992.

Buchanan too knew the story, said Jane Bridges, her partner later in life; it bothered her that Igbo Landing had never received official recognition. “Beverly wasn’t one to shout about this or that, but she would express her anger in a kind of seething way, and that’s one time that I sensed it — that there was no marker,” Bridges said. (St. Simons finally put up a marker honoring Igbo Landing in 2022.)

By contrast, a short walk from the “Marsh Ruins” stands a live oak with a historical marker. Under it, supposedly, Sidney Lanier was inspired in the late 1870s to write “The Marshes of Glynn,” which rhapsodizes the landscape as evidence of God’s glory. Lanier was a Confederate veteran; the marker calls him “Georgia’s greatest poet.”

Buchanan raised none of these matters when preparing her work. She merely sought and received permission from the state marshland authority for “a partially buried sculpture of tabby over concrete to achieve a look of ancient ruins.” But Bridges has no doubt that for Buchanan, building the “Marsh Ruins” at this site was “an act of defiance.”

Still, Buchanan never said directly what the ruins were about. Her choice of site was intentional, but by not publicizing the work and letting it decay, she upended all the conventions of commemoration. Instead, the elements alter the work every day. “While they are dense with situated historical significance,” writes Groom in her book on the “Marsh Ruins,” “they exist in the present tense as ever-evolving forms.”

The “Marsh Ruins” are still listed nowhere. In Brunswick itself, they are barely known, if at all. In emails, both Heather Heath, the director of Golden Isles Arts and Humanities, and John Hunter, the city’s director of planning, development and codes, said they had been unaware of the sculpture’s existence.

Awareness, of course, does not guarantee optimal care. In Miami, Buchanan’s “Blue Station Stones,” which she tinted with a pigment to fade into the stone, got painted over — garishly — in a 2018 “beautification project.” (In an email, Amanda Sanfilippo, the current curator of Miami’s Art in Public Places, said the agency is now looking into restoring them “in a manner consistent with the artist’s original vision and fabrication methodology.”)

The greater risk to “Marsh Ruins” is that someone might remove them, unaware they are an artwork. Perhaps the marsh will swallow them first. But for Burris, they invite a form of conservation that directs care less to the objects than to the artist’s intentions.

The more we think with Buchanan, the better we tend to her work. Thus, the “Marsh Ruins,” for instance, can help us notice the tabby cemeteries dotted around the region. “The memorials are in the landscape already,” Burris said. “Hopefully her work allows us to see them and understand them.”

Still, Buchanan claimed her work. She signed the “Marsh Ruins” in the form of a tiny concrete fragment that she placed in the brush near the roadside. It is badly crumbling, but you can just make out that she etched: “Marsh Ruins, Beverly Buchanan, 7/81.”

Bridges assured me that Buchanan would have been thrilled to see the “Marsh Ruins” make the paper; she cared about her legacy — and this work.

In January 2003, on a road trip from Michigan, where Buchanan had gone to live with her, the two went to look at the “Marsh Ruins.” Buchanan was already out of the car, walking stick and all, before Bridges could park. Then, Bridges said, Buchanan gazed intently and silently at the sculpture for a long time.

“She was absorbing, and I can’t even say what,” Bridges said. “I always got the idea that of all the work she had made and that was part of her, this was the deepest.”

This article originally appeared in The New York Times.