An unusual "holey" rock?

[Chris Gholson 920]

Any idea??? This rock is a strange one. The holes in it are so perfect that at first glance I thought they had been drilled. However, it was picked up on a beach in Oregon by my uncle and he said there were more of them lying in the sand.

 

Does anyone out there know how these nearly perfect holes were formed?

[Rich 7]

Boring Clams.

[Grubstake1 7]

Rock worms. Grubstake

[peabody 1]

Yep, boring clams.

[dick ward 52]

Piddock clams.

[Chris Gholson 920]

Thank you guys for solving the holey mystery, I would have never guessed those clams could bore through rock!

[LipCa 11]

Compressed material, I think?

[Rich 7]

I only knew because I lost a bet years ago about those clams.