Large Stromatoporoid Piece

Description

Another chunk of a mid Devonian stromatoporoid sponge skeleton. The reddish part should be the dolomitize outer part of the skeleton. For some reason the outermost/younger part of the strom didn't have mamelon bumps, even though the inner/older layers did. I have not read much about the stromatoporoid sponge life cycle, but this fossil might be a good example of it. Genus Stromatopora, mid to late Devonian Petoskey Limestone Formation, Petoskey, Michigan, USA.