I am an amateur researcher whose hobby is analyzing Google Earth satellite imagery around the world.
The most common ancient architected structure is what I am calling the "King and Queen portrait", wherein the people of a tribe would build a landscaped figure of their leader or chief, which served as it would today... a "headstone" of where their leader is buried...
Since theire are so many interwoven figures, all over your area, the entire area was in fact the "cemetery" in addition to being the agricultural plots.
This could be a terraced effect on a downward slope, or a stone wall, or many types, but the net effect would be an articulated shape of the head of the King/Queen.
Boston area is saturated with these portraits, and the key is to find the angle of their posture. North, as you may know, shifts 1 degree every 72 or so years, and the Kings/Queens would be positioned towards the setting sun, the West of their time epoch.
Therefore, if these figures are in the North 4 o'clock position, this would mean they are "headed in the 30 degree North" of their time epoch, facing the setting sun of 300 degrees or so, which was their West, the land of rebirth (as the setting sun disappears in the same area, only to be reborn in the East).
The angle of the posture is like a very rough time/date stamp of construction, and I am finding multiple, saturated examples in the Boston area, above ground and on the floors of the Bays and coastal shelf areas.
Hope you enjoy them as I do. I have spotted at least 50 others in the Boston area.