Inwood, in fact, was once country streets. By the late 17th century, after the Europeans arrived, most of Upper Manhattan was owned by two families, the Dyckmans and the Nagles. The terrain west of Broadway was ideal for orchards, and the Cooper Street rock was once part of the Dyckman family farm.

The family auctioned off the area that included the rock in 1871. In the mid-1930s, the developer Morris Abe Goodman and his partners built 60 Cooper, then a rental building. The rock occupied two lots. Mr. Goodman wanted the entire rock but was able to purchase only Lot 25. Lot 27, next to 60 Cooper, was owned by a Bronx resident named Margaret Buchanan.

“My grandfather was a developer and already building three apartment houses in the near vicinity, and I’m sure he wanted to buy both lots, so that he could build another one,” said Mr. Goodman’s grandson Martin Weinstein, a retired lawyer living in Westchester County. “But for some reason he was unable to, so he bought the one lot he could get, which happened to be the one furthest from 60 Cooper. That would at least discourage somebody else from building next to his building.”

Today, the rock is abutted by 60 Cooper Street, as well as buildings on Seaman Avenue and West 207th Street. Though a developer could demolish half of the rock to build an apartment building, nearby dwellings would have to be monitored by the Department of Buildings. There would undoubtedly be noise and structural concerns from residents, many of whom opposed the rezoning.

Alexander’s Garden

About 50 years after Mr. Weinstein’s grandfather built 60 Cooper, the building was converted to a co-op, and ownership of Lot 25 was transferred to it. Inwood, seen as a leafy, commutable, affordable neighborhood, was increasingly attractive to young families.

In 1999, John Buryiak and his wife, Francine Buryiak, bought a three-bedroom, two-bath apartment in 60 Cooper. They often walked their dog past the rock, which was then a blight. “At some point, someone in the building had planted a couple of flowers in there,” said Mr. Buryiak, 53, in a phone interview from Massachusetts, “but whoever did that was gone. When I would walk by, it was basically a dog’s litter box and a dump.”

On Sept. 9, 2004, the Buryiaks had a son, Alexander, and when he was only 4 days old he died of Sudden Infant Death Syndrome.