ID - Hollow coral with gills?

[Lauren16]

Everyone, 

Can someone identify this coral-type fossil?  It's completely empty inside like a clam and has gills like a mushroom.   I've looked through lots of photos in the Forum gallery to no avail. Nothing is even close.  The 'top' isn't flat; it's a dome like the tip of your thumb, with holes on the tip. 

 

In the 'mudstone' matrix there's also a typical rugose coral.  

This was a loose rock in the area of the Kenogami Formation of limestone in Northern Ontario. 

 

Puzzled,

Lauren16

[Pippa]

I think all of it is a solitary rugose coral. The "gills" are the skeleton or structure. 

No idea what caused this specimen to lose its center. But look at the bright side, you get to see it from the inside out.

[Ludwigia]

The "limestones" of the Kenogami Formation are apparently mostly dolomitic, which accounts for the agressive chemical erosion of this horn coral.

[Rockwood]

7 minutes ago, Ludwigia said:

The "limestones" of the Kenogami Formation are apparently mostly dolomitic, which accounts for the agressive chemical erosion of this horn coral.

Must be great for lawns and gardens though.  

[Lauren16]

19 hours ago, Pippa said:

I think all of it is a solitary rugose coral. The "gills" are the skeleton or structure. 

No idea what caused this specimen to lose its center. But look at the bright side, you get to see it from the inside out.

Yes, it is a fine view of the 'gills' structure. 

[Lauren16]

16 hours ago, Ludwigia said:

The "limestones" of the Kenogami Formation are apparently mostly dolomitic, which accounts for the agressive chemical erosion of this horn coral.

re the chemical erosion, What's odd is that the fossil withstood soaking in a vinegar bath without altering, while the 'mudstone' matrix fizzed (as the clay of Northeast Ontario does) and gradually weakened so I could break it apart with my hands.  

[Lauren16]

16 hours ago, Rockwood said:

Must be great for lawns and gardens though.  

The clay soil here in the northeast Ontario "Claybelt" grows vegetation in great profusion, bushes of all sorts, tall poplar trees, which would be great for farming... except for how very heavy the glacially compacted clays are, and how wet the land is, and then the frost in June.

[Ludwigia]

7 hours ago, Lauren16 said:

re the chemical erosion, What's odd is that the fossil withstood soaking in a vinegar bath without altering, while the 'mudstone' matrix fizzed (as the clay of Northeast Ontario does) and gradually weakened so I could break it apart with my hands.  

Vinegar is one of the least agressive acids altogether and is only one of many types of chemicals, like bases, etc. On top of that, the dolomite with its contained fossils underwent countless years under extreme heat and pressure before it was exposed again at the surface.

[FossilNerd]

Nice little weathered rugose coral.  
 

I like to keep a couple of these not so well preserved specimens around. It shows off the internal structure of the coral without breaking/cutting open one that has the outside well preserved. 

[Lauren16]

9 hours ago, Ludwigia said:

Vinegar is one of the least agressive acids altogether and is only one of many types of chemicals, like bases, etc. On top of that, the dolomite with its contained fossils underwent countless years under extreme heat and pressure before it was exposed again at the surface.

Oh OK now I get it, thanks

[Lauren16]

On 2020-04-01 at 12:59 AM, Pippa said:

I think all of it is a solitary rugose coral. The "gills" are the skeleton or structure. 

No idea what caused this specimen to lose its center. But look at the bright side, you get to see it from the inside out.

Pippa, 

Since you and FossilNerd seem to consider this an unusual piece with its view of the gills, should I post this where others can view it, i.e., in Collections? 

What qualifies a fossil to be in Collections? I don't have fossil expertise myself, I'm a beginner. 

Lauren16

[Ludwigia]

3 hours ago, Lauren16 said:

Pippa, 

Since you and FossilNerd seem to consider this an unusual piece with its view of the gills, should I post this where others can view it, i.e., in Collections? 

What qualifies a fossil to be in Collections? I don't have fossil expertise myself, I'm a beginner. 

Lauren16

"Collections" is among other things meant to be a help for clearly identifying fossils and determining their stratigraphy, so your sample would not fit there in my opinion. However, you could open up your own album under "Gallery" where you could show it if you like. It would be helpful if you could use the correct terminology when describing it, since corals don't have "gills".

[Rockwood]

septa > gills 

[FossilNerd]

6 hours ago, Lauren16 said:

Since you and FossilNerd seem to consider this an unusual piece with its view of the gills, should I post this where others can view it, i.e., in Collections?

You can post it for others to see if you like, but my statement was meant as a personal preference for me, and an encouragement to you.  

Some people like perfectly pristine specimens (which are nice!), but I also prefer a few like this in my collection where different parts of the fossil are seen that normally are not. In this case, the internal septa. It would allow me to study, show others, and view them without destroying a nicer specimen.

 

Many people would skip by this one if they were hunting, but for me, all that is gold does not glitter.  
 

I agree with @Ludwigia. If you wanted to post it for others to see, as you mentioned, I’d go with a personal album under Gallery.

 

Lastly, if you do an internet search of "horn coral morphology" you will get a great many helpful diagrams and websites explaining the structure of your find. The internal septa are what is exposed in yours.

LINK

[Lauren16]

1 hour ago, FossilNerd said:

You can post it for others to see if you like, but my statement was meant as a personal preference for me, and an encouragement to you.  

Some people like perfectly pristine specimens (which are nice!), but I also prefer a few like this in my collection where different parts of the fossil are seen that normally are not. In this case, the internal septa. It would allow me to study, show others, and view them without destroying a nicer specimen.

 

Many people would skip by this one if they were hunting, but for me, all that is gold does not glitter.  
 

I agree with @Ludwigia. If you wanted to post it for others to see, as you mentioned, I’d go with a personal album under Gallery.

 

Lastly, if you do an internet search of "horn coral morphology" you will get a great many helpful diagrams and websites explaining the structure of your find. The internal septa are what is exposed in yours.

LINK

Thank you FossilNerd for your advice about posting photos.

And thanks for the encouragement to learn terminology -  the fossil guide book I ordered still hasn't arrived,  so I'm glad  there's the internet. 

[Lauren16]

4 hours ago, Ludwigia said:

"Collections" is among other things meant to be a help for clearly identifying fossils and determining their stratigraphy, so your sample would not fit there in my opinion. However, you could open up your own album under "Gallery" where you could show it if you like. It would be helpful if you could use the correct terminology when describing it, since corals don't have "gills".

Thanks Ludwigia for your advice on posting photos. 

And I appreciate the nudge to use correct terminology (which I'm a stickler for in my line of work because it is indeed helpful to everyone involved). 

Lauren16

[Pippa]

13 hours ago, Lauren16 said:

Pippa, 

Since you and FossilNerd seem to consider this an unusual piece with its view of the gills, should I post this where others can view it, i.e., in Collections? 

What qualifies a fossil to be in Collections? I don't have fossil expertise myself, I'm a beginner. 

Lauren16

Ditto, to what everybody else said above. 

By the way, I'm really still a beginner too, despite the forum's "advanced member" designation. I've only joined TFF last August, after finding a couple of lovely corals that intrigued me.

One thing I learned is to google a specimen's name (once at least the genus is known) along with "morphology" or "anatomy" and click on images. Google then brings up photographs along with graphics that show the correct terminology for the different parts of the fossil.  Have fun fossiling!