ID of lower Chalk ammonite

[Robert Field]

3 fossils from the lower Chalk upper Cretaceous Swanage Bay Dorset 

All look like the same species and came from the same strata

[Tidgy's Dad]

Looks like Scloenbachia varians to me. 

[Robert Field]

Thanks

[Fossildude19]

@TqB @Ludwigia @PFOOLEY

[Ludwigia]

I agree with Tiggy's Dad, but don't forget the 'h' : Schloenbachia

[Tidgy's Dad]

37 minutes ago, Ludwigia said:

I agree with Tiggy's Dad, but don't forget the 'h' : Schloenbachia

Oooops.

Tipsy fingers! 

[Robert Field]

I'm not sure that schloenbachia fits.

I thinking along the lines of an Acanthoceras sp.

[herve]

Hello for me      its an acantoceras   of the cenomanien stage or a cunningtoniceras .  Best regarts

[PFOOLEY]

CENOMANIAN AMMONITES FROM SOUTHERN ENGLAND

[Tidgy's Dad]

Hmmmm. 

I can't see Acanthoceras myself. It's usually more square sectioned than this. 

And he found three. Up to 90 per cent of ammonites found around here are Schloenbachia, (from my experience and the paper above) It would be pretty amazing if they were all Acanthoceras. (though not impossible). 

I'll stick with my original thought for now. 

[Robert Field]

After going through the above paper, most of which is over my head. I went through the plates at the end really interesting and plate 53 stood out to me as my ammonite and referring back to the explanation of that plate it was an acanthoceras jukesbrownie from Clompton Bay on the Isle of Wight which is only across water and can be seen from Swanage.

Why would it be amazing if the were all the same? 

I do have another one

[Tidgy's Dad]

That's a lovely specimen 

You may be right, but look at the interior end of the ribs on yours They end with a big tubercle, stronger than the tubercle on the other end 

I don't think that's true of the ammonites in question, though it's a bit hard to tell for sure 

It looks like the exterior lumps are bigger 

[Robert Field]

Is the interior end nearest the Center then they are larger on the last example but about the same on the others .

 

[michele 1937]

Acanthoceras   Cenomoniano

[herve]

Hello,look this internet site: ammonites et autres spirales,its very interesting. Best regards