unknown pottery

 Wow, those are some very cool bowls, Unfortunately I can't tell you when they were made, or where, but I can tell you that the symbol on the inside of the bowls, despite it's resemblance to the nazi swastika, is actually a far eastern good luck symbol, and is very common on Tibetan and Chinese art. In order to get a realistic idea of age, origin, and value you'd have to take them to an asian art expert for an appraisal. I can also tell you that given the fact that you found them on the beach and the obvious wear on the bowls they are probably washed up from a shipwreck, and could easily be several centuries old. (In modern times the Swastika, when used as a good luck symbol is usually oriented so that the topmost arm faces to the left, so as to distinguish it from the nazi swastika, historically however the direction was not considered as important, and they were done both ways, which would also lead one to believe that they may have some considerable age to them.)

They look very much like fixtures that would be used in a foundry crucibles, kind of hard to tell much else from the images.

This is fascinating. The fact that you found these on a beach is significant, and I agree, there is a potential that they came from a shipwreck from long ago that is deteriorating. In order to preserve any remaining artifacts, maybe it would be a good idea to talk to someone at a local museum and let them know where you found the pieces. Send them the photos of you dont want to get too involved. Give historians a chance to recover history. You may be witness to an amazing historical and even valuable find!

Absolutely awesome!

plus the museum curators might be able to advise you on how to preserve those pieces, and thats important!