Nummulites?

I am pretty sure those are nummilites

I have a lot of them

@a-trilobite and @sameen-zabir thank you so much!!!

Difficult to tell because of mud, but it’s possible. Is this from a caving trip?

@matthew-gramling yes it it!

I’m guess you’re somewhere under the Appalachian Plateau like Lookout or Pidgeon Mtn if you’re encountering Bangor Limestone lol.

Likely some kind of sponge or coral. Try researching the age of the rock you found it in and what animals lived there at the time to find a match.

Probably coral. As @a-trilobite says, you’ll need to figure out the formation it came from to get a better idea of the age and what fossils have been documented. Macrostrat is helpful: https://macrostrat.org/map/#/z=10.3/x=-106.7108/y=39.5487/bedrock/lines/ The White River National Forest is large and is very geologically complicated, with…[Read more]

@a-trilobite and @patrick-hsieh I figured out it’s in the Leadville limestone layer!! I will see if I can find a match!! Thank you!!!

Update us if you find anything, I’m curious to see what this is

Looks like a horn coral to me. GREAT FIND!!!! It’s extended and the tentacles are out! No one finds that!

Rugose coral possibly. (Horn coral)

@marion-marshall wow really? That’s super cool!!! Thank you!!

And @charles-du thank you so much!!!

@a-trilobite look at the comments above!!!!

Wow, tentacles are so rare I didn’t even consider that! Nice find!

It might be a cephalopod, or maybe a turritella Gastropod?

Not a cephalopod. Cross section of a high spiraled gastropod.

It’s turritella then

@riannon-colton I agree with @a-trilobite and @patrick-hsieh that this is a gastropod and likely Turritella.

@patrick-hsieh @a-trilobite @mackenzie-smith thank you so much for the correction and the identification!!!

It’s a turritella Gastropod. If you had the animal/shell rather than a calcite outline it would look like a stone spiral. If I can attach a photo to this answer I will, as I have one.

Ok, I can’t. I’m going to just post the photo so you can see it. Cheers!

The Black Hills encompass a wide area with complicated geology. More precise location or identification of the rocks it came from is crucial. This is the best bet since you can then look up what has been documented in those rocks. Without that, these look like they could be in the Order Orthotetida or Orthida. A view of the interior or the beak…[Read more]

@patrick-hsieh they are from the Tepee Canyon area!!

Looks like the imprint of a shell

Looks like an ammonite.

It’s a large shell, not an ammonite

I don’t see evidence of any sutures or septa so I do not think it is a cephalopod. It is more likely a gastropod.

It’s a Gastropod. 🐌