Jan Somma-Hammel/ Staten Island AdvanceThe new owner of the Neville-Tysen House on Staten Island was in critical condition after falling down a well.

There was much to discover in the nooks and crannies of the massive Revolutionary War-era sandstone house on Staten Island. An October listing by the Gateway Arms Realty Corporation proclaimed the historical relevance of the Neville-Tysen house, named for a retired naval officer on land overlooking the Kill Van Kull.

It also said any deal required cash — $350,000 was the asking price — since no bank would issue a mortgage for 6,000 square feet of badly decaying living space.

“We took experts in and they said it needed extensive renovation,” said Norma Sue Wolfe, an agent with Gateway Arms. “That is where we got that $600,000, or more, was needed to restore it after purchasing.”

On Jan. 5, the seller accepted an offer of $250,000 in cash from Georgia Lind, 65, who expressed an interest in fixing it up to live there and then possibly to sell it as a bed-and-breakfast. The sale went to closing on Wednesday.

On Friday, Ms. Lind was walking around her new home, camera in hand, when one of the home’s secrets unveiled itself: A rotting plywood floorboard covering a 4-by-4-feet opening to an old cistern, which had been designed as a rainwater collection well, gave way; Ms. Lind was seriously hurt when she tumbled 12 feet down to a cold stone bottom that was covered by a film of mud.

Her husband called 911 at 11:40 a.m., said Deputy Chief Roger W. Sakowich of the city’s Fire Department.

When firefighters arrived at the house at 806 Richmond Terrace, in the New Brighton neighborhood, a ladder was lowered to reach Ms. Lind. She was “going in and out of consciousness,” Chief Sakowich said.

The firefighters worked gingerly because the floor of the room they were in was deteriorated and the roof in that section of the home had collapsed.

One firefighter went down with a breathing pack in case there was a lack of oxygen in the hole or a buildup of methane gases as can happen with cesspools. But the air quality was good.

As the firefighters worked, Chief Sakowich was analyzing clues.

He had seen the historical plaque on the front of the house, which he said indicated the house was built in 1770. With a father and brothers in the plumbing business, he was familiar with the remains of cisterns, used to collect rainwater, in the backyards of old houses.

It was apparent that Ms. Lind had suffered a serious blow to the side of her head, either when she fell through the hole or hit the bottom, Chief Sakowich said. He said she was unable to tell firefighters what her injuries were.

More firefighters climbed down, said James Long, a Fire Department spokesman, and started working on Ms. Lind. They stabilized her back, put her on a stretcher and used a hoist to pull her out.

She was listed in critical condition at Richmond University Medical Center. In addition to her head trauma, she suffered a leg injury.

The house’s exact age is a source of disagreement, Ms. Wolfe said. The “greatest expert” on Staten Island, she said, a historian named Barnett Shepherd, believes the house was built just after the Revolutionary War.

“Because of the architectural style,” said Ms. Wolfe, who said it was constructed of massive hand-hewn stones called red sandstones. “Under the paint, there is a fabulous checkerboard pattern of red and white, so the whole house, if the paint were taken off, it would look like a giant checkerboard of red and white stone.’’

But Ms. Wolfe noted that when the city’s Landmarks Preservation Commission designated the home a landmark more than four decades ago, it put the house’s origin to an earlier time.

“They call it, ‘one of the few large pre-Revolutionary houses still standing in New York City,’” Ms. Wolfe said.

Mr. Shepherd, contacted later, said the house was built in 1783, and took its name from Judge Jacob Tysen, a civil court judge on Staten Island who was its second owner, and Capt. John Neville, a retired naval officer who resided in the house from 1868 to 1882 with his wife, Charlotte.

Mr. Shepherd said the man who built and first owned the home, whose name escaped the history books, was Richard Housman.

“It’s not terribly complicated, but it’s a chain of four different owners, and it’s a very old house,” said Mr. Shepherd, who traced the chain of ownership through deeds found in the county clerk’s office and, in 2008, wrote a paper on the house’s history.

An advertisement for the house, published in The Staten Island Advance on Oct. 30, gave some warning about the house’s condition. It said, according to Ms. Wolfe: “Price firm / house not: Landmark needs $600K restoration. Crude bath-heat-lites-fire-water insect ravaged. Mortgage impossible. Proof of funds before visit.”