This is something I have been waiting to see: a rock pile site that is completely inaccessible. Even with lower water levels it would be difficult to get to this island of rock at the northern end of Bare Hill Pond in Harvard, MA.It is visible from Rt 110 just east of where it meets Under Pin Hill Rd. Look out into the water to the south and you see a small island. Again:Look closer and you will see rock piles. Closer:I could make out three in a line. That is a great example of a deliberate impractical construction.
Here is an aerial:
[UPDATE: I was able to get out there, Feb 2013]