Mystery Rocks

Mystery Rocks, Olympic Peninsula

I would love to figure out what these rocks are. I have found them repeatedly among the beach gravels of the northern Olympic Peninsula, along the Straits of Juan de Fuca, but have not managed to figure out where they are from - or what they are.  (I found them in many locations but they are especially abundant around the mouth of the Elwha River)

They are brittle but soft enough that they do not take a polish, despite the superficial resemblance to the Orbicular Jaspers (with red spots) found in the same region.  But the raised dots are odd, and I can't think what rock type these might represent.  Anyone recognize them? The matrix is grey-green and apparently crystalline, but whatever it is, it's a really distinctive rock.

No mineral value, of course, and no one is going to make jewelery from this material, but if there is a geologist out there that recognizes it, or where it outcrops, I'd love to hear about it....

POSTSCRIPT : One reader asked whether the blebs are just surface marks, e.g. barnacle scars, but I broke some open and the spots are distributed throughout the rock.

POSTSCRIPT TWO :  MYSTERY SOLVED 8/26 !  More on a later post...