Two Questions, One Post

[Flinger]

Area: Brandon, MS

Rock Type: Early Oligocene Calcareous Marine Invertabrates

OK, I went back to the quarry and went to a little area kind of off the beaten path hoping to find more stuff. I wish I had pictures of the surroundings but pictures a rock outcrop that has alot of the rock kind of sloughed off due to weather. There is vegetation trying to grow in the resulting debris. The area is pretty grown over. Well anyway I was looking in the debris and I found an area that had hundreds of little snail shells. I will attach two pictures below. Do you guys think these are modern day snails that somehow all decided to die together like some snail suicide pact? Or could these be fossils that washed out of the rock and floated until they got caught up in the dead vegetation at the foot of the outcrop?

I also found what appears to be a sand dollar. So, since there hasn't been any salt water here in a long ###### time, I'm assuming it is definitely a fossil. Can anyone give me a better name for it than a sand dollar? Also, is there a good way to get the rest of the crud off of it? Like a solution to dip it in? Hopefully the pic shows this, but there are little fin areas and the entire surface is covered in little tiny pores(?).

Image 1

Image 2

Image 3

[Auspex]

I can't help with the sand dollar, but the snails are modern (probably "wood snails").

[Wendell Ricketts]

Confirm on the gastropods - they're modern terrestrial snails. Perhaps Polygyra, but a lot of the species tend to look alike. Shouldn't be too hard to ID, though, at least at the generic level, if you do a little web research. Without seeing the other surface of your sand dollar, it's tough to say.

Best,

W.

[Texas-Tunnel Rat]

Confirm on the gastropods - they're modern terrestrial snails. Perhaps Polygyra, but a lot of the species tend to look alike. Shouldn't be too hard to ID, though, at least at the generic level, if you do a little web research. Without seeing the other surface of your sand dollar, it's tough to say.

Best,

W.

Lol, I was going to write the same thing but department meeting got me distracted.

[Fossildude19]

I agree - Modern snails. Fossil echinoid.

Snails like moisture, and maybe the recent heat waves in the mid-west may have caused a bit of a die off.

You could try a small bit of vinegar on the matrix - and see if it fizzles off at all. If it does, make sure to douse it in water to remove excess vinegar - don't want it ruining the fossil.

Some people use wire brushes or a dremel type rotary tool to clean off the excess matrix.

Depends on how fragile the fossil itself is. I'd start with a toothbrush, if that doesn't do the trick, try the harder stuff.

Regards,

[tracer]

i tried to find a bit of info that might be of use to you and i think perhaps you should see what you can find online regarding the mint springs formation and the forest hill formation. i read that cassidulus gouldii was the most common of several echinoid species found in the area i think you possibly could have been hunting, but i'm not at all able to assess what your specimen could be due to it being covered in matrix and only one view of it. good luck with your info quest. it is always nice to find a complete echinoid when out hunting.

good luck with your info quest

[MikeR]

You are collecting in the Marianna or the Glendon Limestones (Formations) of Lower Oligocene age. Fossil gastropods will be internal casts not escargo. The echinoid is probably Clypeaster rogersi (Morton, 1834). See below.

Clypeaster rogersi (Morton, 1834) Loc. No. 976, Lower Oligocene Marianna Formation, Washington County, Alabama.

Edited August 18, 2011 by MikeR