The blow to the head of the man in grave 10 was so severe that it chipped off a bone near his right eyebrow, fractured part of his face, and probably helped to kill him.

He was about 35 years old and likely a slave. He had grooves in his front teeth where he had clenched his clay pipe as he worked, and evidence in his spine that he was engaged in hard labor.

It’s not known exactly what landed him in a hexagonal coffin in the sandy soil north of Delaware’s Rehoboth Bay 300 years ago: An assault, or an accident?

But fragments of his story, along with those of 10 others buried near him, have emerged from an archaeological dig at a long-vanished 17th-century plantation called Avery’s Rest.

They may be the earliest slave remains found in Delaware.

“I think it’s huge,” said Dan Griffith, of the Archaeological Society of Delaware, who helped lead the effort. “It’s certainly the most extensively excavated 17th century site in Delaware … [and] just a fascinating project.”

Research suggests that there was little rest at Avery’s Rest.

“They’re clearing the land, and they’re planting tobacco,” said Smithsonian anthropologist Douglas Owsley, who has studied the bones from the graves. “They’re using their back to haul things that are heavier than” they should carry.

Life could be short. One grave contained a teething infant; another a 5-year-old.

And tobacco was king. The crop was heavily cultivated. It was smoked incessantly in hard clay pipes. And it served as the standard currency.

A good horse was worth 1,500 pounds of tobacco. A frying pan was worth about 25 pounds. Slaves had the highest value — as much as 3,000 pounds each, according to an estate inventory related to the project.

The burial of the slave in grave 10, and two others nearby, show the harsh world in which these early colonists lived.

Interest in the site goes back to 1976, when state archaeologists found a mysterious area of oyster shells, tobacco pipes, and pieces of colonial pottery in a plowed field they were surveying.

“Something was going on there,” said Griffith, then a state archaeologist who helped make the discovery. The experts spent a day gathering artifacts, and then moved on to other sites.

They asked a state historian to see who had owned the land in the past, and were told that it was “Avery’s Rest,” a settlement that dated from the mid to late 1600s.

The homestead was established by an English sea captain and planter, John Avery, then about 42, along with his family and at least two slaves, around 1674.

In 2006, the state discovered that the area might be developed, and asked the volunteers of the archaeological society to help conduct a new dig, Griffith said.

He said the society expanded the dig to an adjacent property over the next few seasons. And in 2012 they found the graves, “which we did not know were there,” he said.

The skeletons were removed from the site in 2014 and taken to the Smithsonian Institution’s National Museum of Natural History, where they remain, for analysis.