Archeologists using 21st-century technology are mapping out the exact spots British soldiers and Colonial militiamen were standing as they fired at each other during a pivotal skirmish on the first day of the American Revolution.

Parker's Revenge, as the fight is known, occurred on April 19, 1775, after the battles of Lexington and Concord as the redcoats retreated to Boston.

Capt. John Parker, commander of the 77-member Lexington militia, had met the 700-strong British column on the green at 5:30 a.m. Eight of his men were killed and 10 wounded.

Undaunted, Parker planned his revenge, positioning his remaining men on a rocky hillside on the border of Lexington and Lincoln and awaiting the return of the British early in the afternoon.

"Parker met a force approximately 10 times his size and took 20 percent casualties on the green, then made the choice to go after them," said Bob Morris, president of the nonprofit Friends on Minute Man National Park. "It's the kind of heroism that cries out to be researched and memorialized."

Morris' organization is financing the project in a partnership with the National Park Service. The 44-acre Parker's Revenge battle site is completely within the Minute Man National Historical Site.

Using ground-penetrating radar, sophisticated metal detectors and other modern-day technology, archeologists and volunteers, led by Meg Watters, have uncovered several musket balls as well as a cast copper waistcoat button.

Some of the musket balls were unfired, indicating where someone stood during the fight, Watters said. Some had been damaged and flattened, indicating they had been fired, and struck a rock or tree, or perhaps even a person, she said.

The nine musket balls recovered so far were discovered in a small area within 80 yards of each other, showing just how close the armies were.

Watters' favorite discovery is the button. "It is gorgeous," she said. "It has a fox, a windmill, a bridge on it, and to think something this delicate has been sitting here for so long is incredible."

The project is expected to continue into November or December.

The artifacts will be placed on display at the park's visitors center, enhancing its educational mission, said park superintendent Nancy Nelson.

The park will eventually install more informational placards, called waysides, at the Parker's Revenge site. It may even restore the wooded landscape so it more closely resembles what the site looked like in 1775.

"This project goes a long way to completing the park's story about what's basically a forgotten battle," Nelson said. "It was a significant and poignant story."