Silurian Sponge? Coral?

[aek]

Hello, I can't seem to ID this fossil found in Silurian reef rock, Chicago area. I made some slices. Any help appreciated.

 

 

 

 

 

 

 

[TqB]

Could be Alveolites - the corallites have a crescentic cross section like yours.

Is there a section where you can see long tubes, perhaps with horizontal tabulae?

[aek]

Thanks for your reply @TqB  I took some additional pics that may be helpful. I really need to get a real lightbox!

 

 

 

[Rockwood]

It's a close call to chaetetid sponge too isn't it ?

[TqB]

 

14 hours ago, Rockwood said:

It's a close call to chaetetid sponge too isn't it ?

You're right, I'd thought they tended to be be more hexagonal than that but there are some chaetetid sponges that fit, especially Ordovician ones according to the unrevised coral Treatise (1956). (They're not in the revised version of course, being sponges). It doesn't help that some alveolitid-like corals were once included in chaetetids, back when they thought they were all tabulate corals. Proper specialist needed maybe. 

 

I can't see any longitudinal sections as in the lower and left part of this (which you'd also get in chaetetids) but that's probably just the direction of the sections. 

https://www.researchgate.net/figure/Colony-of-Alveolites-suborbicularis-from-Uddvide-2-RGM-243-686-showing-preferential_fig9_241887503

 

[fifbrindacier]

1 hour ago, TqB said:

 

You're right, I'd thought they tended to be be more hexagonal than that but there are some chaetetid sponges that fit, especially Ordovician ones according to the unrevised coral Treatise (1956). (They're not in the revised version of course, being sponges). It doesn't help that some alveolitid-like corals were once included in chaetetids, back when they thought they were all tabulate corals. Proper specialist needed maybe. 

 

I can't see any longitudinal sections as in the lower and left part of this (which you'd also get in chaetetids) but that's probably just the direction of the sections. 

(From https://www.researchgate.net/figure/Colony-of-Alveolites-suborbicularis-from-Uddvide-2-RGM-243-686-showing-preferential_fig9_241887503)

 

When i click on your link, it redirects me at the top of this post.

[TqB]

1 hour ago, fifbrindacier said:

When i click on your link, it redirects me at the top of this post.

Thanks, must be because I messed around with the editing. Redone it now.

[aek]

6 hours ago, TqB said:

 

You're right, I'd thought they tended to be be more hexagonal than that but there are some chaetetid sponges that fit, especially Ordovician ones according to the unrevised coral Treatise (1956). (They're not in the revised version of course, being sponges). It doesn't help that some alveolitid-like corals were once included in chaetetids, back when they thought they were all tabulate corals. Proper specialist needed maybe. 

 

I can't see any longitudinal sections as in the lower and left part of this (which you'd also get in chaetetids) but that's probably just the direction of the sections. 

https://www.researchgate.net/figure/Colony-of-Alveolites-suborbicularis-from-Uddvide-2-RGM-243-686-showing-preferential_fig9_241887503

 

 

Interesting. Thank you for looking into this. I will investigate further.