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Quick ?brach ID - UPDATE: Rostroconch


Kane

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Yesterday was chopping through some Dundee Fm (mid Devonian) limestone at a very thick brach/coral layer and found a few of these. The matrix where this is situated in this particular layer has abundant large brachs, gastropods, and large well defined coral colonies. I was just curious as to what sort of brach this may be... if it is one.

1ECA5EA4-DA5A-4AD3-BEE5-4E904EA4F5FB.jpeg

...How to Philosophize with a Hammer

 

 

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Hi Kane, Looks like a partial Rostroconch hippocardia. Rather scarce. Nice find.

 

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Just now, fossilcrazy said:

Hi Kane, Looks like a partial Rostroconch hippocardia. Rather scarce. Nice find.

 

Thanks, John! I think you have it. I had no idea that they were uncommon (the rock had a cluster of them, so I might go back and retrieve those). :fistbump:

 

I did find a listing for a Conocardium cuneus via the UMMP database that corresponds to this unit.

...How to Philosophize with a Hammer

 

 

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7 minutes ago, Tidgy's Dad said:

Nice find! 

Unusual fossils. :)

The more I read on them, the more interesting they become. :) I had encountered these in the past and mistook the rostrum as a kind of rock scraping! Apparently, there was debate as to whether or not they gave rise to scaphopods, but this has been reassessed. They were likely planktonic, closely related to bivalves but *not quite*.  

...How to Philosophize with a Hammer

 

 

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3 minutes ago, Kane said:

The more I read on them, the more interesting they become. :) I had encountered these in the past and mistook the rostrum as a kind of rock scraping! Apparently, there was debate as to whether or not they gave rise to scaphopods, but this has been reassessed. They were likely planktonic, closely related to bivalves but *not quite*.  

Yes, the two halves weren't flexible like a pelecypod, but grown over by shell layers. 

There were quite a lot of species too, for a while. 

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Nice find @Kane! It took me a second to see the split between the valves. At first I thought it was a shark tooth. lol

 

I found a partial one of these in the Lucas dolomite from the Sylvania area, it's missing the part that you have shown though. http://viewsofthemahantango.blogspot.com/2011/06/rostroconch.html

-Dave

__________________________________________________

Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPhee

If I'm going to drive safely, I can't do geology. - John McPhee

Check out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/

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1 minute ago, Shamalama said:

Nice find @Kane! It took me a second to see the split between the valves. At first I thought it was a shark tooth. lol

 

I found a partial one of these in the Lucas dolomite from the Sylvania area, it's missing the part that you have shown though. http://viewsofthemahantango.blogspot.com/2011/06/rostroconch.html

Shark tooth, lol! That was my bad for taking the picture in the mood lighting of the dining room. :P 

 

I did visit your blog a half hour ago to look at your piece (I figured you would have found one). I am gasping for new blog posts there, BTW! :D 

 

I've been able to remove a bit more of the matrix to reveal the 3D features of the valves. I am also going into work early this morning to scoop up the rest of them I left there yesterday. Just in keeping with this topic, I'll have a few more specimens to show later on today. 

...How to Philosophize with a Hammer

 

 

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17 minutes ago, Kane said:

Shark tooth, lol! That was my bad for taking the picture in the mood lighting of the dining room. :P 

 

I did visit your blog a half hour ago to look at your piece (I figured you would have found one). I am gasping for new blog posts there, BTW! :D 

 

I've been able to remove a bit more of the matrix to reveal the 3D features of the valves. I am also going into work early this morning to scoop up the rest of them I left there yesterday. Just in keeping with this topic, I'll have a few more specimens to show later on today. 

Looking forward to see what else you haul back from there.

 

I do need to write some more posts..... Since I moved last year I have been focused on other things and I don't have that nice brick background anymore. :/

-Dave

__________________________________________________

Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPhee

If I'm going to drive safely, I can't do geology. - John McPhee

Check out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/

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I found several of these years ago from (as I recall) the Anderdon sandy facies of the Lucas Formation, in Ingersol ON.  The Anderdon was stripped off and discarded to get at the pure limestone of the lower member of the Lucas.  The lithology looks just like your specimens.  Could that be the source for your material?

 

Don

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1 hour ago, FossilDAWG said:

I found several of these years ago from (as I recall) the Anderdon sandy facies of the Lucas Formation, in Ingersol ON.  The Anderdon was stripped off and discarded to get at the pure limestone of the lower member of the Lucas.  The lithology looks just like your specimens.  Could that be the source for your material?

 

Don

If the material was being dumped wherever the Thames runs its course, it is entirely possible. Along the river it is quite a mixed bag. There is some semi-vigorous transport of material during the spring thaw, but otherwise it is a bit of a lazy river with not a lot of oomph to move stuff very far. I know the river generally runs to the west on the southern branch from Ingersoll, but Western is north of the fork where the current seems to emerge from the north branch, passing through St Marys and Thorndale along the way to campus.

 

Would you happen to have any images on hand to show some example of that facies? The individual fauna in it may not be precise enough to function as an index on their own, but perhaps in conjunction. I am going to have to track down some literature on this, which is somewhat scarce or outdated (at least from what I have been able to track down in the last while). 

 

Next Monday I plan to look for more examples of this particular type of stone and will hopefully have a better "spread" beyond medium-sized brachiopods, these rostroconches, and the occasional gastropod (Platyceras-type). 

...How to Philosophize with a Hammer

 

 

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