Chronicles in the Maastrichtian

[Andúril Flame of the West]

It has been quite a while since I have written a trip report and I thought I'd share the results of some of my most recent fossiling adventures. Before diving into the fossils, this past weekend I had the opportunity to enjoy the beautiful fall foliage of the east coast. The Appalachians, usually quite unassuming hills that are nothing near the grandeur of the mountains to the north and west, were quite a sight to behold. 

 

                                                                                                                                                                                            

 

The fall foliage was clearly quite popular, as I did not expect the entrance to Shenandoah National Park to be quite as backed up as it was. I made it up to the overlook as the sun was setting, as it is said that the colors are most impressive under the light of the westering sun. Unfortunately, the sun was mostly obscured by clouds, but the views were breathtaking nonetheless. 

 

 

Now, for what I am sure everyone has come here to see: the fossils! Over the past couple of months, I have acquired a renewed interest in the fossils of the Maastrichtian Severn formation of Maryland. As any who are familiar with this formation know, it is quite elusive and its most famous exposures were temporary construction sites in decades past. Several weeks ago, I visited a small creek that I had heard exposed the fossiliferous shell layer of the Severn. Initially, exploration of the creek did not seem promising and I only managed to locate only one poor exposure of the Severn at creek level. After some searching and many shell fragments later, I was rewarded with two relatively complete specimens:

 

 

Crassatella vadosa

 

 

Cyprimeria alta

 

Although the yields had not been high, I was quite satisfied with these specimens due to the relative rarity of sites containing original-shell mollusks. A huge thanks to @historianmichael for identifying these specimens and for the preparation tips (unfortunately the shells have begun to crack but I am hoping they may remain salvageable). 

 

 

Inspired by my recent success and hoping for some vertebrate remains, I headed out to a new site. After taking quite a circuitous route through some woods and tall grass I made it to the exposure. The invertebrate fauna at this locality was not incredibly diverse, consisting almost wholly of the oyster Exogyra costata. 

 

 

A handful of Exogyra costata 

 

A more complete specimen of Exogyra costata with both valves intact.

 

After encountering these first few Exogyra, I was left with a few hours to devote to searching for vertebrate remains. With my lack of experience with these fossils and their notoriously poor preservation, I only managed to recover a small selection of possible fragments. 

 

 

The entire haul of possible vertebrate remains. If any members have any insight on whether these are identifiable vertebrate remains, it would be greatly appreciated .

 

Below are isolated photographs of some of the more intriguing finds of the day.

 

This fragment bears some resemblance to a partial mosasaur tooth. However, it may be too fragmentary to assign a confident ID. 

 

 

Scapanorhynchus texanus

 

 

I cannot say what this is, though I am hopeful that it might be bone. I believe that mosasaur and turtle remains can be found at this site. I am very grateful for any opinions.

 

With the weather cooling I do not anticipate that I will be able to get out as often as I would like, but I hope to make a few more forays into the Severn before the year's end. 

 

Thanks for taking a look and happy hunting! 

 

Edited October 30, 2023 by Andúril Flame of the West

[automech]

It's encouraging to see shark teeth in higher locations of MD other than the Bay and Potomac River.

[patelinho7]

I need to get back in on the Severn fun! Glad you got to find some decent stuff. It's pretty rare at this point to find somewhat recognizable vertebrate material. Seems like you had a fun trip. I wonder if your "mosasaur" tooth could be a Ischyrhiza mira rostral tooth? It's a really odd shape and the base seems to have strange curves and folds. And the other long "fanglike" specimen above the shark tooth in the group shot might be an Enchodus tooth. Not too sure, though. 

 

Also, I may have to ask you for advice with locating and exploring Severn sites at some point 

Edited October 30, 2023 by patelinho7

[patelinho7]

Do you think you could provide more photos of the possible mosasaur/ischyrhiza tooth?

[Andúril Flame of the West]

On 10/30/2023 at 2:21 PM, patelinho7 said:

I need to get back in on the Severn fun! Glad you got to find some decent stuff. It's pretty rare at this point to find somewhat recognizable vertebrate material. Seems like you had a fun trip. I wonder if your "mosasaur" tooth could be a Ischyrhiza mira rostral tooth? It's a really odd shape and the base seems to have strange curves and folds. And the other long "fanglike" specimen above the shark tooth in the group shot might be an Enchodus tooth. Not too sure, though. 

 

Also, I may have to ask you for advice with locating and exploring Severn sites at some point 

 

I believe that finding recognizable vertebrate material truly depends on the spot that is searched. At this particular locality the poor preservation works against identification. As I understand it, some of the concretion-bearing layers of the Severn had better preserved vertebrate material. 

 

With regards to the fragment in question, I am not sure exactly what it is. I tentatively called it a mosasaur tooth since the internal texture seemed consistent with photographs of a Severn mosasaur tooth that I had seen. I am not too familiar with Ischyrhiza teeth or chondrichthyan material in general, so it could be a possibility. Here are some additional photographs of the specimen, though I am not sure if they are much better than the original pictures. 

 

 

 

 

 

 

 

 

Edited November 1, 2023 by Andúril Flame of the West

[patelinho7]

Interesting. It definitely screams toothy element from what I have seen of Severn vertebrate material. It does look like that mosasaur tooth described from the Severn in some paper (I forget which, if you have it easily accessible I wouldn't mind reading it again). But that forked shape at the base is very odd. It doesn't look like wear or breakage to me. It really reminds me of the similar forked base of Ischyrhiza rostral teeth.

And the tip of your specimen could be where the root transitioned into the tooth itself. It's not a perfect match, but take an Ischyrhiza tooth and give it a few millennia rolling around in the atrocious preservation of the Severn, and we could get what you have here. But again, I'm no expert either. 

 

The difficulty we will have with getting these Severn finds IDed by experts on Cretaceous marine fossils here on the forum is that nobody is used to the poor preservation of the Severn. Everyone will assume it's not a fossil  . Maybe you could reach out to the CMM, bring it to Dino Park, or even contact the Smithsonian. They would be most well versed with Severn vertebrate preservation.

Edited November 1, 2023 by patelinho7

[Plax]

The shark tooth shouldn't be Scapanorhynchus as they are gone by Severn time. I agree with others re the possible Ischyrhiza rostal tooth.

[Darktooth]

Beautiful scenery and a good haul of goodies!