Green Mill Run NC Fossils (Cretaceous and Neogene)

[Anchiornis]

Hi everyone!

After more than 7 years of putting it off, I finally returned to Green Mill Run last weekend. There were lots and lots of giant Exogyra in the creek, which was interesting since I’ve never really seen trip reports mention those; not sure if something happened to bring them all there. Especially since I assumed most of the Cretaceous stuff in GMR is washed from upstream, but I can't see so many of those big shells being washed all the way to the same spot.

But anyways, here are some fossils I’d like an ID or a clarification on! Ignore the ruler pattern haha

 

Burrow casts? There were a few of these, they looked rock-like but with a unique weight and texture, and they were colored differently from the usual black GMR fossils 

 

Hybodont clasper?

 

I know most/all of these are Squalicorax, including this absolute beast here, but any idea on species?

 

C. hastalis?

Brachiopod?

 

Some kind of shark teeth but not certain about species

 

Either goblin or sand tiger?

 

Bryozoan?

 

 

Thanks everyone!

 

 

Edited December 16, 2023 by Anchiornis

[Praefectus]

Nice finds!

[Anchiornis]

5 minutes ago, Praefectus said:

Nice finds!

Thanks! These are just a few, I have lots of smaller shark teeth, belemnites and around 7 Exogyras the size of my palm or bigger (and none of those big shells required digging or sifting; they were just lying there on the creek bed!). Not bad for a place I haven't come to in 7 years! A friend found a shark vertebra; he kept it since we were operating by finders keepers rules

[ClearLake]

Very nice!  I think your questionable brachiopod is actually a really eroded oyster and your questionable bryozoan is a “wormy” chewed up shell fragment. The holes don’t look organized enough for a bryozoan to me. But maybe some the GMR experts like @sixgill pete will be along to help you more definitively. 

[hemipristis]

1. Yes, burrows

2-3. could be!  Nice

4. Larger: S. pristodontis. Smaller: S. kaupi  

9. Most appear to be goblins

10. goblin: Scapanorhynchus texanus.

 

[Anchiornis]

4 hours ago, hemipristis said:

1. Yes, burrows

2-3. could be!  Nice

4. Larger: S. pristodontis. Smaller: S. kaupi  

9. Most appear to be goblins

10. goblin: Scapanorhynchus texanus.

 

Awesome, thank you! Want some more verification from others about the claspers, those are what I'm the most stoked about since they're actual body fossils 

Can the burrows be assigned to any specific ichnotaxon?
Surprising that almost everything here is Cretaceous, with all the Exogyras I also found, I wonder if the site's "turning more Cretaceous" somehow? Perhaps the creek's eroding more Cretaceous sediments? I don't even remember the 1980s NC fossil book referring to GMR as Cretaceous even though that's obviously not the case

Edited December 17, 2023 by Anchiornis

[Anchiornis]

7 hours ago, ClearLake said:

Very nice!  I think your questionable brachiopod is actually a really eroded oyster and your questionable bryozoan is a “wormy” chewed up shell fragment. The holes don’t look organized enough for a bryozoan to me. But maybe some the GMR experts like @sixgill pete will be along to help you more definitively. 

What oyster do you think it is? Most of the ones I found here are Exogyra so even if it's not a brachiopod it could still be a new species for me

[hemipristis]

2 hours ago, Anchiornis said:

Awesome, thank you! Want some more verification from others about the claspers, those are what I'm the most stoked about since they're actual body fossils 

Can the burrows be assigned to any specific ichnotaxon?
Surprising that almost everything here is Cretaceous, with all the Exogyras I also found, I wonder if the site's "turning more Cretaceous" somehow? Perhaps the creek's eroding more Cretaceous sediments? I don't even remember the 1980s NC fossil book referring to GMR as Cretaceous even though that's obviously not the case

I have found Exogyras when I have collected Ted there, but I wouldn’t have called them abundant.

 

The creek is likely eroding and exposing an area with more Exogyra fossils.

 

As for “turning more Cretaceous”, the Pliocene strata in the area may either be thinner, or less fossiliferous, thus giving the impression that the creek is changing so.

 

Since I started collecting there in the 1990s however, I’ve always been under the impression that most of the fossils to be found were Cretaceous in age, and certainly my finds have reflected that.

[hemipristis]

1 hour ago, Anchiornis said:

What oyster do you think it is? Most of the ones I found here are Exogyra so even if it's not a brachiopod it could still be a new species for me

There are a number of Cretaceous Ostrea species present on the US East coast. Unfortunately, they all appear the same to me

Edited December 17, 2023 by hemipristis

[sixgill pete]

I agree with @hemipristis I.D.'s. The oysters can be very abundant in some areas of the creek. Then they get covered by sand again and you will not see any for a while. Remember that the sand is constantly shifting in the creek. Erosion happens daily on the bottom and banks. 

 

AS far as the "clasper" I would need to see more in focus, close up pictures with the fossil being the central object and from all angels. I have never seen any hybodont fossils from the creek and I am not sure the Cretaceous sediments there are old enough. But it is possible. It has the right shape, but something looks off to me. 

[Anchiornis]

2 hours ago, sixgill pete said:

I agree with @hemipristis I.D.'s. The oysters can be very abundant in some areas of the creek. Then they get covered by sand again and you will not see any for a while. Remember that the sand is constantly shifting in the creek. Erosion happens daily on the bottom and banks. 

 

AS far as the "clasper" I would need to see more in focus, close up pictures with the fossil being the central object and from all angels. I have never seen any hybodont fossils from the creek and I am not sure the Cretaceous sediments there are old enough. But it is possible. It has the right shape, but something looks off to me. 

 

14 hours ago, hemipristis said:

I have found Exogyras when I have collected Ted there, but I wouldn’t have called them abundant.

 

The creek is likely eroding and exposing an area with more Exogyra fossils.

 

As for “turning more Cretaceous”, the Pliocene strata in the area may either be thinner, or less fossiliferous, thus giving the impression that the creek is changing so.

 

Since I started collecting there in the 1990s however, I’ve always been under the impression that most of the fossils to be found were Cretaceous in age, and certainly my finds have reflected that.

Thanks! It's just interesting because I came a couple times years ago and only came out with one Exogyra that was eroded very smooth

When I went there last week I found around 8 baseball-sized (or slightly larger) Exogyra ponderosas all just lying on the creek bed in plain sight and all within a few yards of one another, plus around 5 smaller ones (costata?) with the sifter. And yeah, it's interesting that Cretaceous fossils are very common there, and yet the NC Geo Survey bulletin never mentioned them in its writeup for the site in the Fossil Collecting book. Not sure the level of overlooking that would take, or if something just changed in the creek since that time. Just hoping I can find some marine reptiles the next time I visit.

 

I'll share more clasper pics soon

 

14 hours ago, hemipristis said:

There are a number of Cretaceous Ostrea species present on the US East coast. Unfortunately, they all appear the same to me

I checked the NC Fossil Club mollusc book; assuming this is Cretaceous, seems like an eroded Flemingostrea cretacea. Nice!

[Anchiornis]

2 hours ago, sixgill pete said:

I agree with @hemipristis I.D.'s. The oysters can be very abundant in some areas of the creek. Then they get covered by sand again and you will not see any for a while. Remember that the sand is constantly shifting in the creek. Erosion happens daily on the bottom and banks. 

 

AS far as the "clasper" I would need to see more in focus, close up pictures with the fossil being the central object and from all angels. I have never seen any hybodont fossils from the creek and I am not sure the Cretaceous sediments there are old enough. But it is possible. It has the right shape, but something looks off to me. 

Here are better shots 

[Hybodus01]

Yes Hybodont cephalic clasper

 

[Anchiornis]

3 hours ago, Hybodus01 said:

Yes Hybodont cephalic clasper

 

Excellent, thank you! I guess the hook has been completely eroded leaving only the trident-like base?

 

On 12/17/2023 at 4:00 PM, sixgill pete said:

I agree with @hemipristis I.D.'s. The oysters can be very abundant in some areas of the creek. Then they get covered by sand again and you will not see any for a while. Remember that the sand is constantly shifting in the creek. Erosion happens daily on the bottom and banks. 

 

AS far as the "clasper" I would need to see more in focus, close up pictures with the fossil being the central object and from all angels. I have never seen any hybodont fossils from the creek and I am not sure the Cretaceous sediments there are old enough. But it is possible. It has the right shape, but something looks off to me. 

Since this apparently is a clasper, would this be a new record for this locality?