Construction workers building a new apartment building in the Old City neighbourhood reportedly found some initial remains last fall, and last month, they encountered coffins which have been described as being “stacked three deep.”

The number of gravesites has since been estimated to be as high as 300.

The coffins were part of the First Baptist Church Burial Ground established in 1707. Records show the bodies should have been moved to the Mount Moriah Cemetery in Southwest Philadelphia around 1860, but historians agree that someone didn’t do their job.

In fact, experts have suggested that the task was likely not completed to save money.

The company in charge of the development, PMC Properties, agreed to temporarily stop work on the construction project, but they were given archaeologists excavating the site until March 11 to finish up their work.

Researchers hope to follow through on the original plan and eventually reinter the remains at Mount Moriah Cemetery.

However, before doing so, they plan to study at least some of the bodies and determine characteristics like age, gender, and ethnicity.