Workers upgrading century-old water mains beneath Washington Square Park stumbled on a 19th-century burial vault for the second-time this week, the city's design and construction agency said Friday.

Wooden coffins in the vaults were discovered by the contractors doing the work, which included installing catch basins, sewer manholes, street signage and other modernizing.

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No remains were immediately discovered at the new site, just south of the first one found near Waverly Place and the east part of Washington Square Park, said Shavone Williams of the New York City Department of Design and Construction.

"We have not disturbed or touched any of it," she said of the coffins' contents, which will be examined.

The construction has been stopped as the city's medical examiner, archaeologists and anthropologists examine the site.

It was the second time this week that the city's design and construction agency found a 19th-century burial vault.

On Tuesday, workers doing similar upgrades came upon a big pile of skeletal remains in a vault 8 feet deep, 15 feet wide and 20 feet long. The remains of more than a dozen people were entombed in the vault.