Holy Prasopora

[Caleb]

It's been a slow year collecting and a slow year on finds. I have only gotten out a small handful of times, so when I get the chance to collect I take it! I took a day off work Friday, Sept. 6th and headed down to Southwest Wisconsin to hunt some Mifflin. I normally don't collect during the week but this was a special occasion. Not only was I going to get to collect fossils, but I was going to be collecting with a couple of well respected fossil gurus. I didn't ask permission to drop their names so all I will say is that I often look to their publications for IDs and other references.

Collecting conditions weren't the greatest(very dirty rocks) but we found a variety of typical fossils including trilobite parts, cephalopods, brachiopods and gastropods. The find of the day in my opinion was a Thaleops ovata picked up by one of the gurus, however I'm sure the other guru would disagree with my opinion...

I only brought home 3 pieces. An undescribed Thaleops sp. cephalon and a very large Prasopora, I believe the species is Prasopora grandis. These large bryozoans are not terribly rare, but this one was on the larger side of the spectrum and had a very nice round shape. Most I see look like bulbous masses and I generally leave them behind.

Though the collecting wasn't ideal, the experience was fantastic!

Thaleops sp. "B" (DeMott, 1963)

Prasopora grandis?

Bottom: Top:

and with a scale:

[Ludwigia]

Yes that's a bigun alright, and nicely preserved too!

[Shamalama]

Impressive size on that Prasopora. So what was the third piece you brought back?

[Caleb]

Impressive size on that Prasopora. So what was the third piece you brought back?

The third piece I brought back was a small slab of brachiopods which I'm still working on IDing. I will post a pic of that soon.

[squalicorax]

Are you sure that is a prasopora colony? Looks like a Favosities coral. Very nice regardless.

[Caleb]

Are you sure that is a prasopora colony? Looks like a Favosities coral. Very nice regardless.

I'm pretty sure, I have collected both from the Platteville Formation and this bryozoa is quite common compared to Favosites in this formation. I will post a photo of Favosites from the Platteville when I can get a chance.

[Caleb]

Until I get a photo of Favosites, here is the description for Monticulipora(Prasopora) grandis. I'm not sure if Monticulipora is still the genus or if it is synonymous with Prasopora. Any bryozoa people care to fill me in?

Edited September 9, 2013 by Caleb

[PennyT.]

Caleb, etal. is this prasopora? Found in Maquoketa, NW Illinois

[PennyT.]

And what is this? (the honey-comb texture doesn't show up)

[mikeymig]

I think its a Favosites but again I don't know the formation your collecting in. I love Favosites so I think you had a good day!

Mikey

[Jed '06]

Caleb, etal. is this prasopora? Found in Maquoketa, NW Illinois

Hi Penny,

I don't know what you have there but my grandmother had several of them too. She called them her "stone roses" She got me interested in fossils when I was a small child by showing me her fossils she had collected in Southern Illinois. My first fossils were ones she had given to me. Seeing your picture immediately brought her to my mind!

[piranha]

And what is this? (the honey-comb texture doesn't show up)

It could be the sponge Hindia sphaeroidalis described from the Maquoketa Fm. The attached examples have similar overall morphology and perhaps the honeycomb texture you mention is actually the network of radiating canals, a key feature of this species.

[PennyT.]

Piranha,

sure seems like a good fit, thanks. And Jed, glad it triggered a good memory for you. How wonderful that she got you started on such a fascinating hobby.

[Caleb]

I haven't been able to find much regarding Ordovician Favosites, but the one image I did find seemed to have ornamented corralites that were also larger than .5mm. http://www.uky.edu/KGS/fossils/tabulatemound3.htm. If anyone has information on Favosites from the Middle Ordovician/Blackriveran I would very much like to see it. It turns out I don't have a specimen of Favosites from the Platteville Formation, it was a different type of coral I had collected.

Here's some more images from another baseball sized specimen that was sliced and the top piece polished. The first two images are excerpts from "Lower Silurian Bryozoa" E. O. Ulrich extracted from Volume 3 of the final report of the Geological and Natural History Survey of Minnesota, 1895. The images are based on a specimen collected from the Platteville Formation in Minneapolis, MN.

The first couple images I took show the zooecial tubes. The tubes in these specimens are around .5mm in diameter which is in line with the description posted earlier in this post. This specimen was found in the Platteville Formation of Southwest Wisconsin.

and a larger photo of the zooecial tubes

And here is the sliced specimen

Unpolished bottom wet

Polished top dry. I used 600, 800, and 1500 grit sandpaper to polish this while watching tv. I'm quite pleased with the results for being my first attempt.

Edited October 2, 2013 by Caleb

[squalicorax]

Sweet cut caleb.

[Bev]

Here is a link to what we finally decided were Favorites that I found in SE MN.

http://www.thefossilforum.com/index.php?/topic/38483-prasopora-confirmation/?hl=%2Bbev+%2Bfavosite#entry423270

Congrats on the whooper prasopora!

Edited October 2, 2013 by Bev

[Herb]

It looks more like Tetradium sp to me

Nice sponges.

Edited October 2, 2013 by Herb