Two marks from a saw run along the curved top edge of the 4-by-6 inch fragment, which appears to be from bone at the back and base of the skull. Three small circular markings also seem to suggest attempts were made to drill through the bone.
"It's definitely been sawn and three times someone tried to drill a hole, perhaps in an attempt to treat an injury by relieving the pressure," Bill Kelso, head of the Jamestown Rediscovery archaeological project, told the Daily Press of Newport News.
"But right now it's all preliminary speculation."
The fragment was found during the excavation of a moat outside the west wall of the fort in an artifact-rich area that dates to the first years of the settlement in 1607.
The skull appears to be that of an adult male, but will undergo study by forensic anthropologists with the Smithsonian Institution's National Museum of Natural History to see if there is evidence of trauma, age and ethnicity as well as sex, Kelso said.
The three circular plug marks are typical of those made during an age-old surgical procedure known as trepanation, Jamestown Rediscovery curator Bly Straube said.
Dating back as many as 10,000 years, the practice involved physicians trying to treat head injuries and other diseases by drilling holes in the skull, allowing medicine to be applied, bone pieces to be removed and pain and pressure to be relieved.
"It only took about 30 minutes, but apparently it required some skill," Straube said.
Records from the early years of the settlement show that at least four surgeons practiced at disease-plagued Jamestown between 1607 and 1610. Evidence also shows that London physician John Woodall sent a fully equipped surgeon's chest to the settlement in 1608. The excavations have unearthed two of the instruments from the kit.
The finds, along with the markings on the skull fragment, suggest that colonists fought back against diseases and other fatalities that almost doomed the settlement.
"So many times you hear that the colonists just sat around and did nothing," Kelso said. "But this shows that many of the people who were sent here did what they were sent here to do. In this case we have a surgeon who may have tried to save someone's life — or tried to learn what might have killed them after they died."