Colonial Rugose Coral (species?) and Beekite

[Pippa]

Hi all,I'd appreciate your help with this Silurian Lake Michigan fossil from the Racine formation.

I've done some research and found a family of Silurian colonial horn corals that have members which do look very much like my find. It's the Arachnophyllidae family. I'm not sure if they occur in the Racine formation though. 

Are these badly preserved stromatoporoid mamelons next to the horn coral? The rugose coral is growing on a stromatoporoid reef?

 

Calyce detail:

 

Here is a North American Silurian colonial coral that looks similar. It's Arachnophyllum kayi. Found it in a USGS report about silurian horn corals.  

       

 

 

So now, to the "bumps". Mamelons of stromatoporoids?

 

Thanks so much to everyone for your thoughts and input.

[erose]

Very Very Interesting....  

 

For what it matters the "bumps" look like Beekite to me...

[Rockwood]

Beekite on bryozoan is what I see.

[Pippa]

1 hour ago, erose said:

Very Very Interesting....  

 

For what it matters the "bumps" look like Beekite to me...

Yes, I agree. I do think it interesting too. It's only the second colonial horn coral I've ever found at one of my beaches and it is VERY different from that first one. 

 

Hmm... I thought of beekites too, but have never seen them so worn and "petrified" looking. But very possibly you might be right of course. 

[TqB]

Nice! Arachnophyllum or very similar genus is what I'd have said without knowing the distribution there. The bumps are definitely beekite replacement, apparently of the coral.

[Rockwood]

Why the polka dotted look ?

[TqB]

31 minutes ago, Rockwood said:

Why the polka dotted look ?

Arachnophyllum has numerous small dissepiments, as in this photo of it from the Treatise. Patches of it have the infill dissolved out. 

 

 

[Rockwood]

20 minutes ago, TqB said:

Patches of it have the infill dissolved out.

Somehow I suspect the explanation could go deeper, but that must be the basic idea.

[TqB]

3 minutes ago, Rockwood said:

Somehow I suspect the explanation could go deeper, but that must be the basic idea.

Mineralisation preferentially thickening in the corners perhaps.

[Rockwood]

1 hour ago, TqB said:

Mineralisation preferentially thickening in the corners perhaps.

Throw in a little pneu, some surface tension, and perhaps a dash of polarized molecules maybe ?

[TqB]

34 minutes ago, Rockwood said:

Throw in a little pneu, some surface tension, and perhaps a dash of polarized molecules maybe ?

Sounds convincing and vivid, I can see the fluids creeping...  

[Pippa]

 

10 hours ago, Rockwood said:

Beekite on bryozoan is what I see.

Uggh! Not more bryozoa.  Please say it ain't so!   

Oh, wait a minute, TqB did just that, phew!

 

Thanks Rockwood!

 

4 hours ago, TqB said:

Nice! Arachnophyllum or very similar genus is what I'd have said without knowing the distribution there. The bumps are definitely beekite replacement, apparently of the coral.

Really?  I might not have been totally off-base in thinking that these are the calyces of colonial rugose corals and NOT bryozoans, despite the checkerboard bands? 

 

Thank you TqB for making my day!