UKNOWN ORDOVICIAN FOSSIL

[PaleoOrdo]

I found this strange fossil last time I went on fossil hunting. Could it be a sponge? Anyone have an idea on what this may be?

It was found in Norway, a site of middle ordovicium.

Martin

[Fossildude19]

Photo is a bit blurry. 

Looks like a bivalve to me, but better pictures might help. 

What is the size of the item?

[PaleoOrdo]

Thank for the reply Tim.

The size of the visible part: It is 4,5 cm high and 4cm broad. Probaply in real at least 5,5 cm broad (horizontally) brcause of the mark on the left bottom. The brown color seems to be metallic.

Her is a better picture:

[Kane]

I agree with bivalve. The growth rings are fairly evident. As to its species, that may be tougher to discern for those of us not more intimately familiar with Norway's Ordovician fauna. Someone who does know will likely come along.