Bryozoan? Martin Limestone, Devonian, Verde Valley, AZ

[Doug Von Gausig]

I believe this is a Bryozoan. It is about 14x16mm (about the size of a dime), and is on Martin formation Devonian dolomite from the Verde Valley in Arizona. Any opinions will be appreciated!

[westcoast]

Yes, fenestellid bryozoan, nice.

[DPS Ammonite]

5 hours ago, Doug Von Gausig said:

I believe this is a Bryozoan. It is about 14x16mm (about the size of a dime), and is on Martin formation Devonian dolomite from the Verde Valley in Arizona. Any opinions will be appreciated!

This is a coral, Alveolites which has diamond shaped openings, and not a bryozoan. Are these also from Chasm Creek?

http://viewsofthemahantango.blogspot.com/2016/06/alveolites-sp-coral-from-martin.html?m=1

[erose]

I don't see a fenestrate either. But the angle of the photo makes it hard to tell if this is in fact a flat sheet like a fenestrate bryozoan or if we are seeing surface openings into a mound like coral head.  If it is the later, then even if dime-sized, they are too big for a bryozoan.  

 

Easy rule of thumb is that the zooids of bryozoa are only a fraction of a millimeter were coralites start at a millimeter or more.   Of course there are a few exceptions but they are the odd ones out.

 

 

[FossilDAWG]

I agree with Alveolites.

I never collected in the Verde Valley, but I collected from the Martin Formation in the Catalina and Whetstone Mountains.  Corals and brachiopods were common, but I do not recall seeing any bryozoans.  They may not have silicified as well as the brachiopods or corals.

 

Don

[Doug Von Gausig]

On 12/11/2020 at 12:57 PM, DPS Ammonite said:

This is a coral, Alveolites which has diamond shaped openings, and not a bryozoan. Are these also from Chasm Creek?

http://viewsofthemahantango.blogspot.com/2016/06/alveolites-sp-coral-from-martin.html?m=1

Yes, Chasm Creek (or at least in the same formation). Thanks for the diagnosis! That makes 5 different corals on a single 5-lb. dolomite stone!

[DPS Ammonite]

Have you tried to etch the rock with HCl, pool acid? Most Martin Formation rocks with silicified fossils are limey enough to do so.

 

Here is a picture of some bryozoans found in the Martin Formation north of Payson. Field of view is about 13 mm. I do not recall any from near Chasm Creek, but they might be there.

Have you ever found any Pachyphyllum coral in the Verde Valley? Pachyphyllum is common in  many localities of the Martin.

http://www.thefossilforum.com/index.php?/topic/111035-devonian-coral-inspiration-for-van-gogh-painting/

 

Edited December 13, 2020 by DPS Ammonite