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Middle Jurassic Ammonites, Uk


araucaria1959

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Hello,

many years ago I got some middle jurassic ammonites from UK, but I have no label. Is it possible to tell from the pics, where they come from, and what they are?

I show also the backsides of some specimens because it may help to see the surrounding sediment. The first four specimens are without oolites, the last two ones are in oolitic sediments.

My suggestion for the first four ammonites is Leioceras opalinum from Bridport, but it's only a guess. Specimen 5 looks also like Leioceras, but specimen 6 is possibly different (Graphoceras ?). They also differ because of the oolites so they may be from another locality or another layer.

Thanks,

araucaria1959

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I think your right with Burton Bradstock being the source for these...Leioceras is right I reckon for the first 5 but no 6 as you say is different... I have no ID materials for this stuff as its 'just' out of my collecting field...

Cheers Steve... And Welcome if your a New Member... :)

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Here's my suggestion:

Specimens 1,3,4,5: L. opalinum

Specimen 2: L.comptum, maybe also L.(Cyclicoceras) sp. You'd need the exact horizon to be sure.

Specimen 6: Is definitely a Graphoceras, but the species is not easy to ID. It's not concavum, the navel is too narrow. Perhaps G. pulchrum as first choice or G. cavatum.

 

Greetings from the Lake of Constance. Roger

http://www.steinkern.de/

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Here are two additional specimens. They have a label "inferior oolite, Bridport, Dorset". They remind me of Ludwigia, but seem to be different species (L. murchisonae for the first one, specimen 7?)

araucaria1959

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Those both look like microconches.

Specimen 7: Graphoceras(Ludwigella) ?cornu

Specimen 8: Graphoceras(Ludwigella) rudis

Edited by Ludwigia

 

Greetings from the Lake of Constance. Roger

http://www.steinkern.de/

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Hello,

many years ago I got some middle jurassic ammonites from UK, but I have no label. Is it possible to tell from the pics, where they come from, and what they are?

I show also the backsides of some specimens because it may help to see the surrounding sediment. The first four specimens are without oolites, the last two ones are in oolitic sediments.

My suggestion for the first four ammonites is Leioceras opalinum from Bridport, but it's only a guess. Specimen 5 looks also like Leioceras, but specimen 6 is possibly different (Graphoceras ?). They also differ because of the oolites so they may be from another locality or another layer.

Thanks,

araucaria1959

Could number 6 be Strigoceras truellei or Hyperlioceras discites

Darren.

Edited by D&E

Regards.....D&E&i

The only certainty with fossil hunting is the uncertainty.

https://lnk.bio/Darren.Withers

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I've had a closer look again, also at the last photo, and I still tend to Graphoceras. The inner whorls are too wide for Strigoceras and there's no typical furrow on the side.

 

Greetings from the Lake of Constance. Roger

http://www.steinkern.de/

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