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Eagle Ray Tooth - Severn Formation Upper Cretaceous


MDPaleoceneGeo

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MDPaleoceneGeo

My first post

 

Need assistance with fossil ID.  I believe this is a eagle ray tooth.  Stratigraphic unit is likely Severn Formation, Upper Cretaceous in Maryland.  Found along Magothy River near Ulmstead.  Could also  be from Paleocene Aquia formation as stratigraphic contact in cliff by beach.  If Severn Formation - I believe an early example of ray in fossil record. 

 

 

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Edited by Don Mullis
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Hello from Mount Airy! 

Reminds me of Myliobatis.

I haven’t scouted around there much due to property owners (don’t want to accidentally trespass) but that far north I would guess you are into Cretaceous sediments, probably one of the ones below (just in case you have used the map it’s connected to its all speculatory and usually wrong). A ray tooth wouldn’t be too unexpected from these, what you find would be pretty close to the (older and denser) Moroccan Marine deposits (you may find mosasaur, turtle, and croc remains if your lucky. Heck, the odd dinosaur tooth may pop up) so fish bones/teeth and sharks teeth (squalicorax I know can be found in the Severn FM). You talk of a contact between the Aquia there? I’d like a bit more info on that if you don’t mind.

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Myliobatis is listed in the faunal list for the Severn formation here.

for those who’d rather not leave TFF-

 

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Yes, + 1 for Myliobatis.

Hello, Don, and a very warm welcome to TFF from Morocco! :)

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MDPaleoceneGeo

Hey - thanks for the quick reply.   WhodamanHD - The Monmouth Formation was renamed Severn Formation by James P. Minard in "Geology of the Round Bay Quadrangle, Maryland".    The contact I was referring is not stratigraphic but a disconformity.  Typically the sediments in Baltimore/Anne Arundel County can be diagnosed in the field into Cretaceous versus post cretaceous sediments.   I don't think I see the Brightseat Formation which is the next stratigraphic unit above the Monmouth (Severn).   There is a nice bright orange sandy clay layer between these two on the cliff near the fossil location (see attached).  I think that is the result of iron rich glauconitic sediments percolating down to the top of the more dense and siltly clay Monmouth (Severn).   Always wondered about the K/T boundary here but not sure.   So I think what I am seeing is the Aquia formation (Paleocene) overlying the Monmouth (Severn) formation (Cretaceous) with a stratigraphic disconformity (erosional interval over time) in between.  There are likely some Pleistocene deposits near the top as well. Minard - Geology of Round Bay Quad.pdfMinard - Geology of Round Bay Quad.pdf

 

I'm a 56 year old Principal Geologist (environmental consulting) in Annapolis Area and have done some fossil hunting over the years but my first post to the fossil forum.     This is great way to communicate with the fossil experts :)

 

Attached is pic of fossil location and stratigraphic disconformity (cretaceous/post cretaceous). 

IMG_2839.JPG

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@Don Mullis thanks for the information! It does look like what’s happening, I guess the K-T boundary would only be in the brightseat FM? The Severn is Maastrichtian so getting close. Interesting outcrop you have there, hope it yields some more fossils for you!

Glad you joined! Good to have a geologist around! There are many experts here (and regular amateur fossil hunters like me).

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It might be from the Aquia Formation.
The species described from this formation is Myliobatis copeanus, also present in the Nanjemoy Formation.
The other genera present in the above mentioned formations is Aetobatis with the species Aetobatis arcuatus (=A. profundus).
(see Maryland Geological Survey - Eocene)

 

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Myliobatis is very common in the Aquia formation, just normally nearer to shell beds. I don’t see any shell beds here. I 

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MDPaleoceneGeo

WhodamanHD - Yes - agree.  All my fossils from Aquia are highly iron oxidized and in shell beds or indurated sandstones.  I highly doubt it’s Aquia.  The guy who showed me this location (a young kid) has found very tiny shark teeth in the same beach sands which I believe are from Monmouth.   Hopefully will find some next time I go out.  

 

Also so thanks for the reference to Severn Formation  paper - I had not seen that one before.  Have u been to the site?   It’s not far away.  Is there any shell beds exposed on in construction dump areas?  Know it was along time ago.  

 

Since you are close maybe we go hunting some time.  

 

So why is fossil white versus darker black colors seen in Miocene? 

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You can call me Mason:D

@Don Mullis no problem, Heres the website for the DVPS and it’s one of the only sources of info on these formations (albeit outdated). I haven’t gone to the site, most have been built over or are not easily accessible. Maybe one or two could have survived? 

I haven’t seen any white sharks teeth from either the Aquia (other than one with lightning strikes) or the Cretaceous (well thus far only thing I’ve collected from Maryland’s Cretaceous has been wood, jet, and iron) but wouldn’t be too surprising. I suspect that the clays lend themselves to darker teeth and sands rich with iron are better for white teeth. This belief comes from comparing the east coasts Miocene and oligocene (clay mostly) to California and South America’s Miocene and Pliocene. They are lighter over in California and America. At the cliffs I’ve found a few white teeth that I’m sure haven’t been plant acid or sun bleached, they are rare.

I would love to go on a hunt some time, just shoot me PM! I must warn you I’m fifteen (some take aversion to that).

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  • 2 months later...
On 2/11/2018 at 7:33 PM, MDPaleoceneGeo said:

My first post

 

Need assistance with fossil ID.  I believe this is a eagle ray tooth.  Stratigraphic unit is likely Severn Formation, Upper Cretaceous in Maryland.  Found along Magothy River near Ulmstead.  Could also  be from Paleocene Aquia formation as stratigraphic contact in cliff by beach.  If Severn Formation - I believe an early example of ray in fossil record. 

 

 

IMG_BE0B14A8FCCF-1.jpeg

IMG_86B3710EECA8-1.jpeg

 

Magothy River is mostly late Cretaceous sediments, though there's the possibility that it was eroded down into that area. 

 

On 2/12/2018 at 4:44 PM, WhodamanHD said:

You can call me Mason:D

@Don Mullis no problem, Heres the website for the DVPS and it’s one of the only sources of info on these formations (albeit outdated). I haven’t gone to the site, most have been built over or are not easily accessible. Maybe one or two could have survived? 

I haven’t seen any white sharks teeth from either the Aquia (other than one with lightning strikes) or the Cretaceous (well thus far only thing I’ve collected from Maryland’s Cretaceous has been wood, jet, and iron) but wouldn’t be too surprising. I suspect that the clays lend themselves to darker teeth and sands rich with iron are better for white teeth. This belief comes from comparing the east coasts Miocene and oligocene (clay mostly) to California and South America’s Miocene and Pliocene. They are lighter over in California and America. At the cliffs I’ve found a few white teeth that I’m sure haven’t been plant acid or sun bleached, they are rare.

I would love to go on a hunt some time, just shoot me PM! I must warn you I’m fifteen (some take aversion to that).

 

I never knew you found wood! Care to post any pictures? Is the wood like mine or is it from the Severn? 

 

 

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7 hours ago, EMP said:

 

Magothy River is mostly late Cretaceous sediments, though there's the possibility that it was eroded down into that area. 

 

 

I never knew you found wood! Care to post any pictures? Is the wood like mine or is it from the Severn? 

 

 

Just from Dino park, lignite. Some nice structure in it, so I like it. I also found a piece of jet, which I thought was strange (jet forms in salt water). The staff told me that they think saltwater occasionally washed through during large storms. I’ll get a pic in a few.

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2 hours ago, WhodamanHD said:

Just from Dino park, lignite. Some nice structure in it, so I like it. I also found a piece of jet, which I thought was strange (jet forms in salt water). The staff told me that they think saltwater occasionally washed through during large storms. I’ll get a pic in a few.

Here we are @EMP, crumbled during photographing, not from me but from gravity I assume, just split. Fragile stuff, I’ll glue it and maybe later consolidate and reglue. Plenty at the park, so I’m not too bothered. Jet last (I hope you don’t mind all the pics here @MDPaleoceneGeo

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On 2/11/2018 at 4:33 PM, MDPaleoceneGeo said:

My first post

 

Need assistance with fossil ID.  I believe this is a eagle ray tooth.  Stratigraphic unit is likely Severn Formation, Upper Cretaceous in Maryland.  Found along Magothy River near Ulmstead.  Could also  be from Paleocene Aquia formation as stratigraphic contact in cliff by beach.  If Severn Formation - I believe an early example of ray in fossil record. 

 

 

IMG_BE0B14A8FCCF-1.jpeg

IMG_86B3710EECA8-1.jpeg

 

I would call that a Myliobatis tooth as well.  The genus is best known from Cenozoic deposits but it's been reported from Campanian-Maastrichtian rocks in Texas too.  There's another Severn Formation report (Harstein, Decina, and Keil, 1999) and it has a figure of a specimen.

 

Here's a link to the paper:

 

https://eurekamag.com/research/029/592/029592155.php

 

P.S.  Myliobatis generally refers to bat rays; Aetobatus generally applies to eagle rays

 

 

 

 

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Your jet looks like a dino tooth but probably just wishful thinking on my part.

  Regarding the OP, vertebrate remains are usually concentrated in lag deposits at breaks in deposition. I see a difference in color due to weathering in the section pic but not a pebble lag. Perhaps there's one there that I can't see. There may not be a lag at all in which case the teeth and other resistant clasts may be concentrated at the base of the section by modern weathering. I'd screen the sediment at the base of the section.

  Tooth color depends on a lot of things. Early Campanian Woodbury Formation teeth from NJ for instance (Bellmawr Landfill) are white and in dense clay. I agree that loose sand tends to leach the color out of teeth due to its permeability. Have also seen white or light gray teeth that have been laying out in a pit for a long time that are black on the underside.

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