Bryozoan Fossil ??

[metwerks]

I found this over the weekend north of Milwaukee on the shoreline of Lake Michigan. It looks to be in the Devonian or possible Silurian Period and what I am guessing is Bryozoans from the seafloor of what once was. I would appreciate anyone knowledgeable to confirm. I know these are pretty common finds, but wondering if it is somewhat rare to find this big (11" x 12" x 3" & weighs 24lbs). Also given the dense formation, I assume my guess of being from seafloor is correct?

[Al Dente]

If this is from the Devonian, it could be Idiostroma. Idiostroma is a type of branching stromatoporoid that occurs in large beds.

[Herb]

looks like a nice slab of bryozoans to me

[metwerks]

Thanks....Is there anything that can be used to clean/dissolve limestone and better show of fossil ?

[fifbrindacier]

I vote for a stromatoporoid.

[doushantuo]

The Devonian of the USA has a lot of stromatoporoid float-/packstones,so i go for stromatoporoid as well.

This tubular morphology is also know from some Amphipora species

edit<

Like Al Dente said before me

edit two:the mode of fragmentation of the "twigs" is reminiscent of Amphipora in the Givetian of Germany

Ramose (/arborescent)morphologies abound in the fossil record.

Most of the time you need ultrastructural (e;g. from thin sectioning)data to tell them apart

 

[fifbrindacier]

1 hour ago, metwerks said:

Thanks....Is there anything that can be used to clean/dissolve limestone and better show of fossil ?

You can wash it with water and a tooth brush, but i don't think it is worth to do more than that, your plate is very nice like this.

[metwerks]

Here are maps of geographical area. While I found in the "Devonian Zone" (first pic) vs Silurian (2nd pic), I could not say which it is. Not sure if the era dictates what it might be

[Archimedes]

Definitely a lot of Bryozoans in the rock, nice specimen

[tmaier]

Wow, dense cluster of branching bryozoa. I've never seen it so thick.

To clean it...

1. Toothbrush and soapy water to remove organic schmutz (oil based grime). Then rinse.

2. Toothbrush and diluted vinegar to remove hazy limestone dust. Rinse. Doing the soap first allows the vinegar to do its job. Oil based grime blocks the vinegar from getting at the rock, so you need to strip the oil first.

3. Some people put them outside (when there is not freezing) to be bleached by the sun and erroded by the rain. Nature seems to prep these types of fossils pretty well. Don't leave it out during freeze/thaw, or nature might crack it apart.

A lot of the yellow and orange might stay, because it isn't surface "dirt", it is deep mineral staining.

Some people bleach these, but I'm not too keen on that because bleaching is only temptory. But, bleaching can give a temporarily new view of the fossil.

[metwerks]

5 hours ago, tmaier said:

Wow, dense cluster of branching bryozoa. I've never seen it so thick.

To clean it...

1. Toothbrush and soapy water to remove organic schmutz (oil based grime). Then rinse.

2. Toothbrush and diluted vinegar to remove hazy limestone dust. Rinse. Doing the soap first allows the vinegar to do its job. Oil based grime blocks the vinegar from getting at the rock, so you need to strip the oil first.

3. Some people put them outside (when there is not freezing) to be bleached by the sun and erroded by the rain. Nature seems to prep these types of fossils pretty well. Don't leave it out during freeze/thaw, or nature might crack it apart.

A lot of the yellow and orange might stay, because it isn't surface "dirt", it is deep mineral staining.

Some people bleach these, but I'm not too keen on that because bleaching is only temptory. But, bleaching can give a temporarily new view of the fossil.
 

Thank you....good info. 50/50 dilution?

[tmaier]

"50/50 dilution? "

Yeah, good enough. Actually, even full strength shouldn't hurt it much, but diluting it slows it down and the smell is less over-powering.

You need to keep an eye on how aggresive the vinegar is towards the fossil. You don't want to get so aggressive with it that you start to erode the fossil. Vinegar is an acid and attacks these things, but it is a mild acid (that is also good on a salad).

And rinsing is important because otherwise it will continue to attack the fossil.

Cleans it up good, for better viewing.

[fifbrindacier]

1 hour ago, tmaier said:

And rinsing is important because otherwise it will continue to attack the fossil.

And the salad.

[abyssunder]

Acid rain would be sufficient ...

[doushantuo]

Amphipora packstone:

 

[metwerks]

3 hours ago, doushantuo said:

Amphipora packstone:

 

That looks like cat litter - LOL. How big is this piece?

[metwerks]

[Coco]

1 hour ago, metwerks said:

You cheat ! They are granules for rabbit !

 

Coco

[fifbrindacier]

On 9 novembre 2016 at 8:46 PM, Coco said:

You cheat ! They are granules for rabbit !

 

Coco

Yeah, but fossilized granules !

[Coco]

For fossil rabbits ?

 

Coco

[fifbrindacier]

Or for fossilized Jackalopes ?