What is this?

[citrine.colubrid]

Just came back from a short trip to the driftless region of SW Wisconsin and we found a strange fossil in a road cut. I thought it was an algae at first, but I can't find any similar images. Sort of just looks like the rims of a rugose coral, but tiny? Found in Platteville formation. 

 

[Tidgy's Dad]

Maybe one of the encrusting heliolitid corals that show septa, something like Protaraea. 

Does it look encrusting, rather than massive? 

 

[oyo]

Whenever I think of Heliolitidae I visualize much more developed septa than that. When I see those septa so short, just spines, I think of Favositidae corals.

Although it should be noted that these critters are not my strong suit at all. Maybe @TqB or someone else wants to have an opinion or comment.

 

[Rockwood]

I think I may need to vote none of the above. I don't think it is coral.

[Al Dente]

It reminds me of Pleurodictyum but I don’t think they are found in the Ordovician.

[westcoast]

1 hour ago, Al Dente said:

It reminds me of Pleurodictyum but I don’t think they are found in the Ordovician.

I agree, maybe Formation information incorrect or.. maybe earliest record...

[minnbuckeye]

1 hour ago, westcoast said:

maybe Formation information incorrect

The driftless area is  Ordovician, maybe some Cambrian in the deepest valleys. The term is used for an area that I live in that escaped the advancement of all the glaciers. This also means no rock could have been transported here during the ice age either.  I have seen millions of driftless rocks and haven't come across this.

 

 Mike

[TqB]

I think it's a favositid as @oyo suggests, perhaps a Paleofavositinid which often have many septal spines. (It won't be a heliolitid as they by definition have 12.) There are quite a few to choose from and I think you'd need more sections and very probably a specialist.

 

Here's a Paleofavosites -  a bit fuzzy, but the septal spines are clear. It also has irregularly sized and shaped corallites  similar to the OPs.

 

 

Edited October 24, 2020 by TqB

[oyo]

Some plates of species belonging to the genus Paleofavosites. They come from FOSSILID.INFO.

Attached link: https://fossiilid.info/1809?mode=in_baltoscandia&lang=en

 

Paleofavosites luxuriosus Klaamann, 1962

 

 

Paleofavosites jaaniensis Sokolov, 1952

 

 

Paleofavosites juuru Klaamann, 1959

 

[citrine.colubrid]

Thanks for the help, guys. I'll have to look into this genus more at some of the local species

[TqB]

11 minutes ago, citrine.colubrid said:

Thanks for the help, guys. I'll have to look into this genus more at some of the local species

It's just one possible genus out of the group - local species lists might be helpful.

Edited October 24, 2020 by TqB

[Rockwood]

9 hours ago, TqB said:

Paleofavosites

 

 

9 hours ago, TqB said:

It also has irregularly sized and shaped corallites

First prototype out of the shop always needs some refinement.

[erose]

3 hours ago, TqB said:

It's just one possible genus out of the group - local species lists might be helpful.

Definitely a coral but as TqB suggests you will need to find out what species are known from the formation.  May be a few others similar to Paleofavosites.