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Kehbe

Possible Pennsylvanian Sponge?

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Kehbe

I found what I think is a badly weathered example of a partial Pennsylvanian heliospongia. I suppose I am looking for someone to verify or refute my ID. It wraps around and down the back side a bit but I didn't spin it around to show. I will take another picture if someone needs it for a better ID. Thanks for looking! :)

pic1 post-7046-0-92968400-1326399008_thumb.jpg pic2 post-7046-0-90824500-1326399031_thumb.jpg

Pennsylvanian heliospongia, Kansas City, Jackson county, Missouri.

Edited by Kehbe

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Missourian

It appears to have the typical surface texture of a Heliospongia. Is it silicified?

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Kehbe

It appears to have the typical surface texture of a Heliospongia. Is it silicified?

Missourian,

If it scratches glass, it is silicified? These scratch glass. I just have an old pane of glass from a garage sale picture frame and i used it for testing. I didn't want to push to hard because i didn't want to break the sponge but it did scratch it. I went back by the spot I found the first one and lo' and behold, I found another piece that I think is a better example. Here it is...

post-7046-0-57998300-1326507291_thumb.jpg

If I were to use muriatic acid on this, roughly what concentration of acid to water? Do I have to worry about the other fossils on the piece? I should stop the acid reaction with baking soda and water and at what concentration? Sorry for asking so many questions and I am working on reading through some past posts on acid treatment but thought since you recently performed this procedure, you might have some fresh suggestions! Thanks! :)

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Missourian

They most likely are silicified, but it's still always safe to first test a mediocre piece in acid.

First, try to find a container as small as possible to do a sponge so you don't have to add an excessive amount of acid. A Rubbermaid food container was the perfect size for mine. If you like, you can move the sponge and acid to a smaller container as the piece is reduced in size. Of course, you can always save any unused acid for later.

With my Heliospongia, I didn't dilute the acid at all. I just let it eat away until the fizz died off, and then added some more. I was still experimenting at the time, but I liked how well -- and quick -- it cleaned off the sponge. The reaction should work at a wide range of concentrations.

I rinsed the sponge in a bucket of water. As HCl is highly soluble, it should wash away pretty quickly. If you still smell the acid in the sponge, dunk it again. As HCl is a gas, any that remains will eventually dissipate with the moisture. I didn't even use gloves when I pick the sponge out. I just rinsed my fingers off when I doused it in the bucket. You don't have to do it like me, but I came out of it intact. :) Oh, and do it outside.

As for other fossils, they will probably dissolve away. For some reason, only these sponges attracted the silica. If you want to retain any surrounding matrix, then much more care is needed. Unless the matrix is attractive, I'd be inclined to just do a total dissolve. My goal of soaking the sponges is to reveal the intricate structure inside and out.

But still examine the piece as the acid eats away. The acid could leave an attractive bit of matrix behind in mid-dissolve.

And be careful with the sponge when it is complete. I found that mine was so well cleaned, the individual spicules were coming off on my fingers.

Edited by Missourian

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Missourian

Also, in which limestone bed did you collect yours? They seem to appear in more and more layers.

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Kehbe

I found it in the top layer of this cut...

pic1 post-7046-0-81433300-1326513806_thumb.jpg

this is up the street 50 to 75 yards to the right of pic1

pic2 post-7046-0-68760600-1326513829_thumb.jpg

hash slab lying on the ground at base of the wall shown in pic2...

pic3 post-7046-0-92149000-1326513845_thumb.jpg

close-up of a piece that is similar to what the sponge pieces in this post looked like in situ...

pic4 post-7046-0-58204600-1326513924_thumb.jpg

of course, this is Kansas City, jackson county close to Raytown. I think I may have PM'd you about this site a month or so ago, I know I posted some pics of hash pieces I found here a while back.. Link.. http://www.thefossil...__fromsearch__1

Hope this helps! :)

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Missourian

The top layer in the first pic is the Bethany Falls Limestone. I haven't seen any sponges come from it.

Those Heliospongia seem to keep popping up everywhere. :)

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Kehbe

In pic1 you can see some yellowing areas in the Bethany Falls limestone. As this exposure continues furthur to the east, the ground rises and the cut starts dissapearing into the ground. It is in this 'yellowish' area, to the east of the big picture of the cut that I found the sponges and the second round of hash in the link I provided. Up in the exposure that hasn't been freshly blasted but instead is naturally eroding. I think the blasting destroys the sponges. I am going to try to go back by there today if it warms up at all. As for Bryozoans, I found a pill bottle full of small pieces, (twigs), right where you said they would be, in the Middle Creek limestone. Other than what I have mentioned and a few scattered Brachiopods, this area is not real fossiliferous but the sponges make it worth going back for a third look! :)

Edited by Kehbe

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Missourian

Sponges are probably present on the fresh surface, but they may not be so easy to make out. The ones I've found were weathered to some extent and stood out in relief.

They may also be found in the soil as residuum.

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