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Tripermiblast

While collecting at a location in SE Virginia which produces a mixture of material from the Eocene Nanjemoy Formation and late Miocene/early Pliocene Yorktown Formation, I was shocked to find what I believe to be a cretaceous Globidens sp. anterior tooth fragment.  My only explanation for this would be that it must have been redeposited into the Eocene beds and finally exposed with rest of the material.  The texture is classic Globidens.  The only other species with a slightly similar texture found within these formations (though still markedly different), would be Squalodon sp., however if the tooth were more complete it would clearly prove to be hollow with a conical interior consistent with squamates like mosasaurs.  The fragment is approximately 7/8" x 1/2".  This is the first bit of possibly cretaceous material I have found from these exposures, so it would be quite interesting if the general consensus is a Globidens sp.  Your thoughts would be much appreciated!

Thanks,

Ash

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Edited by Tripermiblast

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Tripermiblast

Does this appear to be a Globidens species tooth fragment?  Any other ideas?  I would really like to hear what others think.

Thanks,

Ash

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FossilDAWG

@MarcoSr has enormous experience with these formations, and he likely can offer an authoritative suggestion.  The fossil does not look very toothy to me but I don't have a lot of experience collecting those horizons.

 

Don

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Plax

I wouldn't rule out a terrestrial animal tooth fragment. I don't know of any Eocene terrestrial mammal teeth being found in the nanjemoy but there's a lot I don't know. The ornamentation is unusual that's why I'm suggesting this is something we don't usually see in the area.

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Tripermiblast

    Thank you for the replies.  This was found on a bank of the James River in Prince George County, which is private property, and rarely ever collected from.  For that reason I will rule out another collector dropping it on the beach.  The enamel's pattern of peculiar ridges and valleys seems nearly identical to Globidens, but comparatively very different from early cetaceans that had bumpy textured or striated teeth.  It is hard to tell from my photos, but this tooth is not bumpy.  There is a quarry maybe 4 miles away (Vulcan) in which a pocket of the Cretaceous Potomac Formation has produced insect and plant material.  The range of this formation and it's relationship to the Nanjemoy and Yorktown are unclear to me.

    And that is true, I haven't really considered a terrestrial species.  After 15 years of collecting from this location, I have yet to find any definitively terrestrial material, but that is a possibility.  Though when considering possible terrestrial species, I am even more at a loss.  I am not letting the affinity to Globidens blind me, but it is striking.

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MarcoSr
14 hours ago, Tripermiblast said:

    There is a quarry maybe 4 miles away (Vulcan) in which a pocket of the Cretaceous Potomac Formation has produced insect and plant material.  The range of this formation and it's relationship to the Nanjemoy and Yorktown are unclear to me.

  

 

The Cretaceous Potomac Formation extends from New Jersey to southern Virginia.   The Traditional view of the Potomac Formation is that it was deposited in a fluvial environment.   Plant and insect fossils would definitely fit within this fluvial environment.  Out of the Potomac (three divisions of the Potomac are formally recognized: the Patuxent, Arundel, and Patapsco), the Arundel Clay is the only one that contains an appreciable vertebrate fossil record.  The Arundel Clay has produced dinosaur, mammal, reptile and fish vertebrate fossils.   If you want a good overview of the Arundel Clay environment check out the paper at the below link:

 

https://palaeo-electronica.org/content/pdfs/847.pdf

 

The paper’s conclusion : "Traditionally,  the  Arundel  has been  interpreted  as being  of  fluvial  origin,  deposited  in  a  freshwater  system  of  stranded  channels  or oxbows. Based on faunal composition, together with published geological and sedimentological  evidence,  we  propose  that  at  least  some  of  the  Arundel  facies  was deposited in close proximity to the Atlantic Ocean."

 

Whether you consider the environment as fluvial or near Atlantic Ocean brackish water swamp, you wouldn’t find Globidens in this environment. Take the specimen to a museum for a proper id.

Marco Sr.

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