Two holed clamshell button?
Let me wander. Even if it isn't! You found a button. Got me thinking clams and history....
An old timer , now long gone ended up in a room above a bar. Seems it was four bucks a night back then.
Waitresses used to sneak him a hot dog now and then. Or more often.
Wearing a sweater in summer , he'd visit with patrons.
Told me of his youth about a half hour South working a river there with his Dad collecting clamshells to sell for button material...
Cincinnati had a button factory.
Of course , buttons from clams came from many sources/states.
In the 1860's the rush was on in Ohio to search for freshwater pearls from clams. (It had started in New Jersey with a large pearl found.)
Like many areas...The poor clams suffered dearly. A lot of them had to be killed and gone through to find a pearl. Let alone a good one.
Today many states don't allow harvest.
And in my state not that long ago some folks got busted for harvesting clamshells.
They were taking the hinge areas thick parts (what wampum used to be made from) , grinding it to shape and putting them in oysters to get cultured pearls...
Pearls being layers of deposits the shellfish build around a trapped irritant.
What inspired Ohio as a search place?
[At archaeological sites throughout the eastern United States, huge caches of pearls have been unearthed, over sixty thousand of them were excavated from a mound in Ohio’s Little Miami Valley. It’s little wonder given the native inhabitants close and prolonged association with the great mussel beds lining our rivers, that pearls would play an important role in their lives as well.]
"Pearl" buttons could be from clams.
Some old timers would run one (note two holed vs four) on their ice fishing line for an attractor.
The pic. is not from our area.
But there are accounts of natives using shell to make decoys for spearing through the ice in winter. (?)
Well, it should be all here.OK OK no CW or RW, but yes to NA, and I wouldn't be surprised to learn that there was underground railroad activity here. It's all over this area. 
