Capt. John Baker, died in 1781, aged 75.
Roslindale is not the sort of place you associate with the Revolution, but it turns out a cemetery there, by the side of a road Washington's forces used to ferry supplies from Dedham to Boston, was the final resting place for a number of Revolutionary War soldiers.
You can see the remains of the Walter Street Burying Ground on Peters Hill in the Arnold Arboretum. Go into the Peters Hill entrance of the Arboretum where South Street meets Walter Street and start up the path on the hill. As you walk, keep in mind that back in the day, Roslindale as a place didn't exist - the area was a hinterland of the town of Roxbury. And Walter Street, then known as the Dedham Road, was a key supply route for the Americans.
When you get to a fork, take the right one. You'll go past some houses on the right and then you'll see some tombstones down the hill, including the above one for Capt. John Baker, who died in 1781 - aged 75. In 1902, when Walter Street was widened, workers found the remains of 28 people, presumed additional soldiers. Their bodies were reinterred at Mount Hope Cemetery, rather than up the hill.
There's also what looks like a crypt built into a mound - which is what it is, holding the remains of American soldiers who died of smallpox at the Loring-Grenough House in nearby Jamaica Plain during the siege of Boston - when the house served as a military hospital. The soldiers, now all unknown, were originally buried beside the house, but in 1867, they were reinterred at Walter Street.
In 1923, the city council authorized the removal of the stone wall that had marked the cemetery on two sides, so that the Arboretum could plant the tulip trees that still stand there today.
H/t Seth Gitell for alerting me to the burying ground.