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Richard
Can anyone help with identification of this specimen?
Found in Middle / Upper Chalk of Southern England.
It measures 1cm across.
I originally thought it was a bivalve but now wonder if it could be an aptychus? 

DSC02998.jpg
Richard
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andrasz
The photo is very blurred, cannot tell whether there is any shell remaining or it is just an imprint. If the latter, you could be spot on, aragonite dissolved in chalk leaving ony imprints, while sturdier calcite shells (eg. echinoderms and some bivalves) survived.
 
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prep01
Yes - too blurred and need more of them (including one of the block its in) from different angles please. Can you also say exactly where it was found (including onfo on type of site eg quarry,road cutting beach etc)- for the geology.
I have a suggestion)!
Regards

Colin Huller
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Rolo
 Looks somewhat similar to the sponge Porosphaera patelliformis .
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Richard
Thanks for contributions so far. 
It was found in a road cutting just north of Hambleden, a village between Henley-on-Thames and Marlow
The geology map shows the location as being where middle chalk meets upper chalk i.e. immediately below the Chalk Rock.
However these maps are not that accurate and so it could be upper chalk. 
It is an imprint (no shell present) and about 1 cm across
Here are better? pictures

DSC03002.jpg   
DSC03002 - Copy.jpg  i
Richard
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prep01
Hello Richard, I think it's an impression of a bivalve.
Colin Huller
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Richard
Thanks all for replies
Colin - are you thinking Inoceramid bivalve?
Andrasz - perhaps juvenile bivalve with thin shell - so not preserved?

Richard
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andrasz
Cannot tell really. Chalk bivalves usually have the shell preserved regardless of thickness, but it could be that what you have is an internal mold with the shell remaining on the counterpart. Perhaps you can try delicately prepping the lower part where it disappears under an overlying layer, that should split off easily.
 
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prep01
Richard, are you able to reveal any more of it yourself or if you're passing through Dunstable, I would do it for you in a few minutes. I would then have another go at ID. Oh, looked up the geology around Hambleden and it's either Lewes nodular chalk or Holywell nodular chalk, 88 - 93.5 mya.
Colin Huller
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Richard
Thanks Andrasz and Colin

I will attempt to reveal more and post results
Richard
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andrasz
Taking a good second look at the better photos I'm inclined to lean towards aptychus rather than bivalve, mainly on account of the preservation.
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Richard
Andrasz - thanks for giving this more consideration.
I cannot find any shell material so have decided (tentatively) that it is aptychus. 
Richard
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prep01
I think Andrasz is correct! I've done some 'digging' (sorry) and found this paper https://www.kreidefossilien.de/assets/files/sharpe_1853-1857.pdf look at plate XXiV.
Colin Huller
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Richard
Colin - thanks for your reply - the paper may be ancient but is very useful - I have saved it for future reference. 
Richard
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Fossilamn14
Internal cast of a bivalve. Are you sure that that is middle/upper chalk, it appears to have lots of Glauconite present, it looks more grey chalk subgroup/lower chalk?
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Brittle Star
Colin is an extremely experienced member of this forum and usually has evidence to back up his ID, along with other experienced members to confirm or give other informed ideas. Also please be aware of the date of the last reply, this one was back in August, it appears you have been going through old posts.

Please introduce yourself if you have degrees or qualifications in certain subjects or if you are an expert on specific areas. This will help members know who you are. Replying to a new person using scientific jargon will not help, keep it simple and to the point.
JW

 Never ask a star fish for directions
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ThomasM
well personally I have to agree with the above poster that it's definitely a bivalve! The growth lines are completely unlike those of aptychi. Preservation wise looks fine for bivalve, the shell has just come off with the counterpart. Not sure why the absence of any shell suggests aptychus - they are calcitic like many chalk bivalves so I wouldn't expect them to suffer the same type of dissolution that the aragonite shells of chalk ammonites do.

cheers
Thomas

If you don't look, you won't find.
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Richard
Fossilamn - definitely NOT lower chalk - I think the photo came out greyish.
Thanks ThomasM - bivalve it is.


 
Richard
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Fossilamn14
Hi, Brittle star, in reply to your comment, I am a fossil collector on the Isle of Wight I have found 7000 fossils since I started collecting, I work in a Paleontological museum and specialise in Cretaceous ammonites. My main areas of collecting are the Lower greensand Group in particular the Perna bed member and the Crackers member of the Atherfield clay formation, the Wealden group; Wessex and Vectis formations, The Selbourne group mainly Upper Greensand, the Solent group (Oligocene/Eocene) at Hamstead/Bouldnor and in particular the Glauconitic marl of the lower chalk. I am 17, I  currentely run Wight Coast Fossils and finish my A-levels in June from then on I will go on to do a degree in Palaeontology. My name is Jack.
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Richard
Hi Jack
And welcome to the forum - I think your knowledge will be very useful here. 
Good luck with your A levels (i.e. work hard!).
Where do you hope to do your degree? 

Richard
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Fossilamn14
Hi Richard
Thank you, hopefully it will :-)
Thank you, I am doing History, Maths and Biology unfortunately Geology at my VI didn't run. My two main candidates are Portsmouth; Four year Bachelors and incorporated Masters in Palaeontology, and Bristol; three year Bachelors in Palaeontology and Evolution.
Jack 
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MicroFossilMan
Jack - if you can get the grades for Bristol, I'd choose that! If you've any money left you can always do a Masters afterwards! And, as Cambrian Rockhound said, your detailed knowledge of the IOW will be very useful for those who have fossils from there and are not sure what they are. Like me 😉
MFM
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Fossilamn14
I went to open day a couple of weeks ago and really liked it, I thought it was an incredibly beautiful city and university, I really liked the look of the Palaeontology and evolution course. I have got an open day booked at Portsmouth on the 6th, I will have a look and see what I think of it. I really did like the look of Bristol though so if I do get the grades I would go there. Hopefully my experience of collecting on the island will be useful on the forum:-) On the Bristol course we go to the Island in the second year so I get the feeling it will be very useful then :-)
Jack
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prep01
Hello Jack. it is very difficult when people just 'pile in' without introducing themselves and the profile section has been reduced and not everyone used to reveal themselves! I joined this forum almost when it started (can't remember the year - it was re-configured in 2009 and our posts were reset to zero) I have 50 years experience of collecting and my library and PDF's are pretty extensive and have various contacts. I have been prepping professionaly for nearly half that time. I also ID on other forums and FB pages. I'm not saying I get it right every time though!
Colin Huller
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Brittle Star
Hi Jack

Thank you for your introduction. The location section on this site is really user friendly for new collectors, pointing new people in this direction gives them an over view of what is available in different areas without blinding them with science.

Hope you did not take offence with my previous post, it is a matter of not putting new people off that do not gave a science background.

By the way my name is NOT Cambrian Rockhound, that is just a title the same as Newbie.
I think it denotes how long people have been on the forum.
JW

 Never ask a star fish for directions
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MicroFossilMan
Brittle Star wrote:

By the way my name is NOT Cambrian Rockhound, that is just a title the same as Newbie.
I think it denotes how long people have been on the forum.

Oops! I knew that, a senior moment [redface]

Didn't there use to be other categories, Cretaceous something, Jurassic something, Triassic something?
MFM
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Fossilamn14
Hi everyone, nice to meet you all, hopefully I will be of use, Brittle star; no don't worry you really didn't I understand what you mean.
Jack
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Brittle Star
MUM

Yes there were different ones, I don't know if it is just me but now you get to Cambrian after just a few posts. Hopefully it does not go on how old you are. Otherwise I will be working towards the time when the earth was still forming.
JW

 Never ask a star fish for directions
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prep01
Janet, don't fret! It used to be number of posts (1 -25 Cretaceous climber; 25 - 500 Triassic Titan or something like this). Remember, your age is just a number!
Colin Huller
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MicroFossilMan
When I was a lad the base of the Cambrian was placed at 600 million years ago. Now it's 541 MYa, so as I've got older the Cambrian has got younger 😉
MFM
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Brittle Star
Sorry MFM

Auto correct kicked in, you are not my mum. So I am younger not older. Not sure if that makes me feel better or not. :)
JW

 Never ask a star fish for directions
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