Is This A Colonial Coral

[JimB88]

anyone know there Mississippian corals? This is the first Ive found in the Bangor..

appreciate the help

[JimB88]

No one even cares to look...

[Auspex]

I'm lookin'; just trying to find a head-scratching smiley!

What's the scale of these things? Are they bryozoan small?

[JimB88]

thats what I forgot. There as big as a dime in diameter.

[FossilDAWG]

I'm thinking yes, although as Auspex said it would be good to have something for scale. Hard to generate a more precise ID without that info, and maybe a longitudinal section if one shows on the side of the rock.

Don

[JimB88]

I'm lookin'; just trying to find a head-scratching smiley!

What's the scale of these things? Are they bryozoan small?

in case your wondering the reason for the comment was after two hours it still hadn't been viewed.

[Herb]

It sort of looks like a bunch of horn corals in living position weathered down, especially with the 1" diameter size. The is a colonial coral "Lithostrotion sp" in the Mississippian, but in the one's I have the coralites are only about 1/4 to 3/8 " in diameter.

[FossilDAWG]

in case your wondering the reason for the comment was after two hours it still hadn't been viewed.

Well, considering it's the weekend maybe everybody is out fossil hunting. Everybody else, that is; I'm still wrestling with my tax return. Word to the wise: a few hundred dollars in consulting is not worth it, considering all the extra paperwork for the social security, medicare, and other taxes that weren't deducted off the top.

If those fossils are the size of a dime, they are definitely corals. Perhaps Caninia or Lithostrontion/Lithostrontionella.

Don

[Auspex]

in case your wondering the reason for the comment was after two hours it still hadn't been viewed.

I guess I pass without leaving footprints; I posted on my third look.

[JimB88]

It sort of looks like a bunch of horn corals in living position weathered down, especially with the 1" diameter size. The is a colonial coral "Lithostrotion sp" in the Mississippian, but in the one's I have the coralites are only about 1/4 to 3/8 " in diameter.

Thats originally what I was thinking as there seems to be a lot of space between the corallites

[Fossildude19]

Jim -

Pretty neat looking, whatever it is - wish I was stronger on Corals.

I have seen Lithostrontionella that large, though.

Regards,

[howard_l]

They are coral and they look like Lithostrontion now named Acrocyathus .

But they are not Colonial (Tabulate Coral) It is a Rugose Mound Coral. Very common in the Mississippian St Louis Limestone at least in Kentucky.

[Jurassic Jim]

Agree lithostrotion sp. corral, know a few locations in the bangor of N. Alabama where the ground is littered with both solitary and "clumps" like the one you found.

[howard_l]

The first picture is Lithostrontion (Acrocyathus) replaced by pink chert, the second picture is of single corals after acid treatment also Acrocyathus.

The last two photos are Lithostrontionella. Lithostrontionella occures with the coralites touching. Lithostrontion (Acrocyathus) occures with space, sometimes noit much between the coralites.

[TqB]

The nomenclature is confusing here: I believe Lithostrotion is still valid but restricted to the cerioid (honeycomb like) forms. The branching species, where the corallites have space between them, are now included under Siphonodendron which is possibly what Jim has here - but see below.

Lithostrotionella is a completely different cerioid genus which the Treatise (Hill 1982) suggested not be used at all and for which the older name Acrocyathus might be appropriate (at least for some species).

The corallites here look as if they might be a lot wider than at first glance, possibly even cerioid, with the outer dissepiment area partly recrystallised so you can't see it properly, which makes Acrocyathus (or Lithostrotion) a possibility - Acrocyathus has wide, bubbly dissepiments quite different from Lithostrotion.

It really needs a polished section to see the stucture properly.

This is all according to the Treatise - does anyone know any more recent systematic work on these? I've collected a lot of Lithostrotion and Siphonodendron here in the UK but we don't seem to have Lithostrotionella/Acrocyathus around here.

Edited April 17, 2012 by TqB

[crinoid1]

I have corals like that from here in Huntsville, AL. I have them labled as Canina. Please excuse the terrible pictures. I took them when I was just learning how to properly take pictures of fossils.

[FossilDAWG]

Here's a link to an older paper on Kentucky Mississippian fossils. Your fossil seems similar to what is shown in the paper as Lithostrontion proliferum (Hall) from the St.Louis limestone. The genus name may require updating. What do you think?

I have some Canina from northern Alabama in which you can see smaller corallites budding off the mature ones, giving rise to clusers of individuals with diameters similar to your specimen. However, these are arranged in circles as they bud off the edge of the mature coral, which is typically an inch or more in diameter.

Don

[howard_l]

When I was in School at Morehead and Eastern in Kentucky I was taught it was Lithostrontion. The Kentucky Geological Survey publications now calls it Acrocyathus. That doesn't mean what was found in Alabama isn't Lithostrontion. The main thing I was pointing out was these are not Colonial (Tabulate Coral). They are considered Rugose Mound Coral.

[howard_l]

From the KGS web page

Acrocyathus is a type of rugose coral mound. It was previously known as Lithostrotion. In this fossil you can see that the corallums (tubular chambers) between each calyx are very thick. That's because each corallum is cemented to the next, rather than having shared walls as occurs in tabulate colonial corals. Acrocyathus (Lithostrotian) corals are common in the Mississippian-age St. Louis Limestone. Often the fossils are silicified, which means the original limestone was replaced with silica (quartz). Because quartz is more resistant to weathering than the surrounding limestone rock, fossils of these corals commonly weather out of natural outcroppings, or are eroded in stream banks. Some may even be replaced with agate, which is a variety of quartz.

[JimB88]

A rugose mound coral? Never thought of that. Im assuming the septa then would be the same as lithostrotion. I'm also thinking that this may be more of a negative than positive..I cut a piece off but it showed no structure beyond the surface. However, since it appears to be in a chert-like material, which isnt common at this locale; I should be able to locate the source.