Possible Rudist?

[Kato]

Okay, in our area we aren't supposed to have Mesozoic layers due to an unconformity....but...is this a rudist?

 

 

 

 

 

[Kato]

Back side view. Speciment is approximately 1.75" thick and constant diameter top and bottom. 

 

[DPS Ammonite]

You have a Paleozoic horn coral. What fossils are associated with it? 

[Kato]

5 minutes ago, DPS Ammonite said:

You have a Paleozoic horn coral. What fossils are associated with it? 

That's what I thought when I first saw this speciment. What throws me is that the diameter is constant for the entire thickness of 1.75". The top and bottom exposure are of relatively the same diameter.

 

The horn corals we find here are often of that length (1.75") but with the obvious taper like this one I found in November 2018

 

[DPS Ammonite]

Some corals are several inches long and are roughly the same diameter over part of their length. Caninia is one such long coral: https://en.m.wikipedia.org/wiki/Caninia_(coral)

[Kato]

2 hours ago, DPS Ammonite said:

Some corals are several inches long and are roughly the same diameter over part of their length. Caninia is one such long coral: https://en.m.wikipedia.org/wiki/Caninia_(coral)

Thanks! That does seem the most obvious answer. I will need to wrap my head around the idea and do some online research of formation studies. Of the historical documents and studies done since the early 1900's for this area the Caninia is not listed. It is listed in a formation that we do have locally, but 100 miles west of where this one was found.

 

Thanks again! 

[Kato]

19 hours ago, DPS Ammonite said:

You have a Paleozoic horn coral. What fossils are associated with it? 

Bump. Asking for corroboration from another seasoned expert to confirm DPS Ammonite's opinion this specimen is a Caninia. 

 

From online reading of research papers, if it is a Caninia, it is nearly 2x larger in diameter than those listed in Lake Valley, NM where the largest diameter found found was 28mm. This one being right at 50mm.

 

Just want to make sure I document it properly. Thank you for any additional thoughts...

 

[DPS Ammonite]

I do not know if this is Caninia. I just used it as an example of a coral that does not uniformly taper. It can be roughly the same diameter over several inches of its length.

 

Your coral is probably only identifiable by an expert looking at a thin section of the coral.

[abyssunder]

1 hour ago, DPS Ammonite said:

I just used it as an example of a coral that does not uniformly taper. It can be roughly the same diameter over several inches of its length.

I wanted to say, but you said it already.

 

 

 

[abyssunder]

Can we have a picture showing how it looks from the marked side with the facing side (one cent side of the coin) on top in a higher resolution picture?

 

 

 

[Kato]

15 hours ago, abyssunder said:

Can we have a picture showing how it looks from the marked side with the facing side (one cent side of the coin) on top in a higher resolution picture?

 

 

 

 

Top view (approx diameter = 50mm). Maybe a crinoid remnant in the middle?

 

Side view. Nothing is revealed of specimen

 

Bottom view

 

 

[abyssunder]

Thank you for the nice pictures!

The top and the bottom side have the same morphology. Rudists don't have this kind of septate, lamellar, radiating pattern. Some rudists (like hippuritids) have similar shaped upper valves, but the patterns are only on that valve, so it might be misleading.
Here's an example from here :

 

 

[Kato]

30 minutes ago, abyssunder said:

Thank you for the nice pictures!

The top and the bottom side have the same morphology. Rudists don't have this kind of septate, lamellar, radiating pattern. Some rudists (like hippuritids) have similar shaped upper valves, but the patterns are only on that valve, so it might be misleading.
Here's an example from here :

 

 

Thanks to both of you for the identification. For now, I will label the specimen 'horn coral', possibly Caninia.