Joey-
I’ve found dozens of eye bolts set in outcrops or large boulders across Gloucester. This one (see attached) is from Dogtown. There are many throughout the woods of West Gloucester. Typically I find them at the top of the outcrop or rock, often with a piece of wire still attached. They are much smaller than the beefy hardware associated with quarrying.
What were these used for?
Nick
Good Morning Gloucester 
I would guess a guy wire to support a derrick for quarry work. Some small quarry pits (motions) were very small and might use just a few guy wires to hold a small derrick to lift out the granite. Johnsons Quarry in Rockport still has a derrick of the very large kind.
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~ as a young girl i always thought they were used as anchors??? :o)
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I’ll bet Les Bartlett would know. He has a wealth of knowledge on all things quarry and such.
http://www.naturalstonephotography.com/index.html
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Someone should do a story on these old stone relics.
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The eye bolts I can sort of figure out. Must be a guy wire suport for something. The straight iron poles about 3/4 inch diameter not so much. Did a pulley attach here? Then there are the weird ones. I cleaned off a bit of Atlantic Path a month ago and a 3/4 inch bar comes out of the rock then ends which what looks like the claw on a hammer. Was it to pull nails out of boards passing by?
I can send photos, if Les Bartlett can come up with an answer. I know what a plug and feathers is but that took a few years to figure out who to ask.
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They look a lot like the basis of shackles to me
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