Rockport MA Rock Pile

Reader Mark A writes:

I grew up in Rockport Massachusetts and at the top of a hill are two large piles of rocks. I was wondering if you have any thoughts on their origin I do know the site was once the location of
a house-turned-hospital, but these are not foundation stones to my eyes. Here are some images:
http://eoinvincent.com/blog/turtle-rock/
http://harmonyclubwaltz.blogspot.com/2007/03/just-ducky-and-puzzle.html

And here is a writeup of the hospital:
http://vintagerockport.com/2011/02/14/leander-m-haskins-hospital-rockport-mass-1907/