Shovel, Wetsuit Are Tools for These Archeologists

It was tough digging for archeology students Erin Head and Matt Napolitano.

Cold seeped through their wetsuits. Dislodged river muck swirled through the water like cream stirred into a cup of coffee. Visibility was only inches.

“Some days you can’t see your hand in front of your face,” said Head, standing waist-deep in a Hudson River bay.

So it goes in the submerged world of underwater archeology. Instead of wearing khakis, diggers this summer at Croton Point Park donned wetsuits and scuba gear as they unearthed discoveries beyond the reach of landlocked archeologists. Daria Merwin and a team of students found buckets full of submerged stone artifacts where the Croton River flows into the Hudson, about 30 miles north of New York City.

“I know it’s stone tools, but it’s stone tools people haven’t seen in a few thousand years,” said Merwin, an adjunct professor at Stony Brook University.

The prehistoric tool makers didn’t live underwater. The creeping sea level over thousands of years is believed to have submerged settlements that stood by the water’s edge.

The dig site today is a peninsular park by a commuter train station and the suburban bustle of Westchester County.

But thousands of years ago, it was a wild area with easy access to sturgeon, berries, oysters and fresh water -- a great spot for hunters and gatherers, according to Merwin. She was enticed to the site by a local man’s discovery of washed-up artifacts.

Merwin, whose underwater work has included shipwreck searches in the Hudson, recently devoted the first half of a six-week summer course in underwater archeology to the Croton site.

The work is typical archeology -- sites are meticulously mapped into grids and methodically dug out. Complications arise from doing it underwater.

Pairs of divers follow a tape line about 150 feet out, then dig exploratory holes every 15 feet as they work back to shore. They use scoops of the sort found in hotel ice machines. Metal screens are used to sift the silt.

Results are logged on clipboards, though divers write on waterproof Mylar instead of paper. Low tide allows the divers to use snorkels.

The work can be time-consuming.

But one advantage of working underwater is that organic materials like leather and wood are better preserved, said Donny Hamilton, head of the Institute of Nautical Archeology at Texas A&M; University.

More than 100 stone artifacts have been bagged and tagged in the three weeks. Many of the artifacts are “cores,” heavy stones from which spear points or other tools were made. Some artifacts are “flakes” or leftover chippings from tool making.

Working under hazy skies, Napolitano and Head found a good example of the latter -- a finger-sized gray rock with ragged edges chipped on either side.

“Holy cow, that’s a big flake!” Merwin said as she waded out to examine her discovery.

That find was trumped later in the day by an arrowhead -- the first fully formed tool found at the site -- dug up by another pair of students.

The find created a buzz among the students, in part because the arrowhead is a datable object. Based on the design, Merwin believes it is roughly 2,000 years old.

Merwin noted that finding artifacts in the water does not necessarily mean there was a settlement on that spot. Objects could have washed up there. But Merwin said these artifacts have minimal signs of wear, which usually means little or no water movement.

The group will next explore off New Jersey’s Sandy Hook, the aptly named peninsula jutting into the Atlantic just south of New York City. Merwin noted that it was a Hudson site thousands of years ago. A recent dredging project turned up prehistoric artifacts, and her divers will go 50 feet down to find more.

Eventually, she’d like to go upriver again.

“This is essentially a pilot study,” Merwin said. “I’d like to take another look.”