Natur is a wonder in its self!!!!!
yummy for this creature that had the good parts of this stone ;-)
It might be some kind of fossils. It could be because the stone also looks like some kind of lime stone. Fossils are usually formed in those kind of stones :). They are beautiful!
As far as I know such stones are not homogeneous, so the sea water is washing out the softer parts more quickly.
I know what you mean Rita, I will try to find it out and solve the riddle.
I think it is as Rita said, I find them here too.
I found out there are definitely living organism!They live in and from the limestone.alas I only found a german version, but the Pictures tell the Story as well.....http://azalas.de/blog/?page_id=176