From 1870 to 1890, thousands of people were buried at the Mt. Pleasant Plains Cemetery in Adams Morgan in D.C. Starting in 2005, the area was surveyed to discover the history of the place and determine what traces remain. (Mary Belcher)

Every city is a palimpsest, the new put down over the old, just as the old was put down over the even older.

That’s what Answer Man thinks when he walks through Walter C. Pierce Park in Adams Morgan. Last week’s column was about Walter Pierce, the man — the man who turned a vacant lot into a place for neighborhood kids to play. This week’s column is about Walter Pierce, the park — or, rather, the many things the roughly five-acre patch of ground overlooking Rock Creek has been over the past 200 years.

Katie Davis has observed the more recent aspects of that history. She was 10 years old when her family moved to Adams Morgan in 1968. She knew Walter Pierce, the namesake of the park on Adams Mill Road NW who died in 1991.

Davis captured the spirit of Pierce Park — and of the diverse neighborhood it serves — in an NPR radio essay in 2003. Of particular interest to her were the garden allotments that then fringed the northern edge of the park.

These were not orderly or neatly delineated. They were leafy microcosms of the neighborhood itself: idiosyncratic, of various sizes, tended by people of different nationalities. The plots — some of which tumbled down the slope — were assigned by an immigrant from Martinique named Don Victor Zebina.

Davis oversaw a youth group that worked a plot in the park.

“All we were growing were zinnias,” she said. “One day, I came, and the whole garden had been dug up into rows and rows and rows. I knew that this Albanian guy had done it.”

Davis complained to Zebina, who explained that the Albanian man had recently arrived in the country and was growing food for his family to keep from going on public assistance.

“I thought, ‘Okay, that’s a good reason,’ ” Davis said.

The park was a multifarious space, its many constituencies working side by side like the characters in a Richard Scarry Busytown book.

“It was kind of nice,” said Davis. “If you had a family, you could be in the garden with the little kids. The preteens and teens could be playing basketball. The little toddlers could be in the children’s section. That’s what I remember. It was a neighborhood park just filled with people doing different types of things, all kind of coexisting.”

It was while gardening in her own plot one day that Davis came across a reminder of the land’s earlier use: a handle from a casket.

“It was sobering to find it,” she said.

Davis gave it to the people who were trying to harvest an earlier history from the park.

“People tend to think of cemeteries as sad places,” said Mary Belcher, historian for the Walter Pierce Park Archaeology and Commemoration Project. “I would say they’re not sad places. What’s sad is when they’re desecrated. Otherwise they’re wonderful. People can connect with their ancestors and their history.”

The history of the cemetery begins when there were working mills on Rock Creek. One mill would eventually be bought by John Quincy Adams, giving Adams Mill Road its name. In 1807, a Quaker burying ground was established nearby. In 1870, the Colored Union Benevolent Association — a fraternal order started by free Black men in 1838 — founded Mt. Pleasant Plains Cemetery adjacent to the Quaker graveyard.

The two cemeteries closed in 1890 as development spread. As is often the case with African American cemeteries, the remains were not treated with care. Some bodies were moved when Adams Mill Road was widened. When the site was prepared for possible development in the 1950s, great quantities of dirt were moved around.

Belcher enlisted the help of Howard University biological anthropologist Mark Mack to study the area using noninvasive methods.

“We found the exposed remains of at least nine individuals on the surface of the earth in various hidden parts of the park,” Belcher told Answer Man.

Later surveys with ground penetrating radar found more than 30 intact graves.

Meanwhile, researchers sifted through 75,000 death certificates at the D.C. Archives and discovered the names of 8,428 individuals who had been buried on the land. Among those buried there were people who had tried to escape to freedom in 1848 aboard the Pearl and soldiers who had served in the U.S. Colored Infantry during the Civil War.

Records show that as the land was readied for potential development, fewer than 300 graves were removed, suggesting that many remain. (If you have a District ancestor who died between 1870 and 1890, you might find them in the database at Walterpierceparkcemeteries.org.)

In 2005, the D.C. Department of Parks and Recreation closed down the gardens for an erosion prevention project. The garden plots were never reinstated. Signs were erected describing the historic cemeteries.

The entire park is more button-down than it was in Walter Pierce’s day. In addition to basketball courts, there’s a dog park and a playground. What was once a scruffy ballfield is now a billiard-table smooth pitch behind locked gates and available only by reservation.

That’s what the park is today, anyway. As for what it will be tomorrow, only time will tell.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/john-kelly.