Possible Ordovician Graptolite?

[connorp]

I found this small specimen in the Platteville Formation (Middle Ordovician) in Wisconsin. My first reaction was that it might be a graptolite fragment, especially as it looks to be preserved as a carbonaceous impression. However, I would appreciate a second opinion. Thanks!

 

[Bob Saunders]

looks like Halysites fossil chain coral. 

[Ludwigia]

I agree with Bob.

[daves64]

+ 1 (or would this be 3?) for chain coral.

[TqB]

I think the scale's wrong for a halysitid. It's only about 1cm across - here's about the same area of a Silurian Halysites. 

If it really is carbonaceous then a dendroid graptolite is likely though the pores are very crisp and it would be a beauty!

Or possibly it's a bryozoan, which was my first impression.

 

Halysites:

[connorp]

It does resemble a halysitid, but I didn't even consider it since I was under the impression these rocks (~455 mya) were too old for tabulates.

[doushantuo]

Let's call it Catenipora

[Rockwood]

Camp dendroid graptolite is where I stand.

[westcoast]

The overall branching pattern doesnt look like graptolite to me, also the preservation doesn't look carbonaceous, but that may be just the image.

[TqB]

5 hours ago, doushantuo said:

Let's call it Catenipora

The apertures are much too small - tho colony here is only 1cm across.

Catenipora corallites are about 0.6 - 1.2mm across. These are about 0.25mm. Also, there are the sections with double rows and the spacing is very uneven. 

 

[Johannes]

Maybe a bryozoan colony? Maybe Phylloporina reticulata, Nematopora sp. or similar species?

[TqB]

I'm going for bryozoan too now. A knowledgeable friend has pointed out that the apertures seem to rotate around the stems, rather than being on one surface. Also, there's a complex 3D arrangement of crossing over stems in the bottom area. Neither of these fits dendroid graptolite. Also, it doesn't look carbonaceous though of course photos can be deceptive.

[FossilDAWG]

I agree with bryozoan colony.

 

Don

[doushantuo]

I had read 

 

 

when i voiced my opinion