A pit behind a shopping center in New Jersey may hold a rare collection of fossils from a mass extinction that wiped out many dinosaurs. As a university nears purchase of the land, researchers and members of the public continue to unearth new findings.

Long a source of marl, a sandy substance used for water treatment plants, the quarry in southern New Jersey’s Mantua Township also contains a concentrated layer of sediment containing a “mass death assemblage,” according to Kenneth J. Lacovara, a professor of paleontology and geology at Rowan University.

Lacovara believes the fossils found in the quarry may come from animals that died out all at once and settled to the bottom of a shallow sea situated where the quarry is today, the New York Times reported. Many of the skeletons of larger animals are still intact, suggesting to researchers their simultaneous demise.

“It sounds silly, but is it the case that this pit in South Jersey, behind Lowe’s, has the one window into this pivotal moment in time?” Lacovara said.

Yet this hypothesis – that the remains found in the quarry by university researchers and “citizen paleontologists” alike come from a remarkable mass extinction event – has yet to be proven.

The fossil layer is 66 million years old, which is believed to correspond quite well with the impact of a meteor off the Yucatan Peninsula in Mexico that triggered the mass extinction of about three-quarters of the species on Earth at the time – particular grounded dinosaurs. Yet there is no clear evidence of the quarry’s link to a mass extinction, Lacovara said.

“We are in the trying-to-poke-holes-in-it phase,” he said. “There’s going to be so many arrows aimed at that.”

The quarry’s preservation has not come without adversity, as it was almost buried nearly ten years ago.

Once Inversand, the company that had dug marl from the quarry, closed the site due to financial problems amid the 2007 recession, the pit nearly became a residential and shopping development. Lacovara proposed preserving the quarry for both professional and amateur researchers.

“We really want to integrate this in the community,” he said, stressing the public’s desire to preserve the quarry. “It’s a living, changing place.”

When Inversand warned that they were going to shut off the pumps that keep water out of the pit, Lacovara appealed to Rowan University’s president, Ali A. Houshmand, who agreed to buy the quarry. The university is set to finalize the deal this month, NYT reported.

In the meantime, the quarry has been periodically opened to the public, allowing citizen diggers to keep many of the fossils they unearth.

“I found a pile of rocks,” Alexandra Hopper, participant in a recent community digging event, told NYT. “When we rinse them off, we’re hoping some of them are fossils.”

With the quarry’s future intact, Lacovara said his team is moving full speed ahead in search of conclusive answers to the questions posed by the pit’s fossils.

“Certainly we have rocks that are near that time,” he said. “I know we’re damned close.”