Tiny mystery seeds

Good day all,
I've found a large pile of tiny seeds and am having difficulty identifying them. I believe that they are indigenous to the Comox Valley or at least to Vancouver Island.
I hope somebody is up for the challenge and can identify these for me!

(Note: The grid paper used in the photograph is ruled in 5mm squares.)

I should probably provide some manner of description: one side is smooth and rounded while the other has a slight ridge.

 

Can you describe the hows and whys of the pile of seeds you found?

 

They were recovered during an archaeological excavation.

 

Hmm... well, here's one resource: http://westerncascades.com/photos/seeds/. If that's a dead-end, also try http://botanyjohn.org/gallery/v/ubcbgseed/

 

Thanks for the resources! It is appreciated.