Macrocephalites id and prep

[elegantoceras]

Looking for some advice and id beyond Macrocepahites. The ornementation on the body is rubbish but on the keel going into the aperture is v good. How much further back would you take it?.Thanks

[andreas]

8 hours ago, elegantoceras said:

How much further back would you take it?.Thanks

Maximal to the end of the bodychamber.

I can not see this on your pic. Please look where the suture pattern start.

This is the end of the bodychamber. But the pattern can only be seen without shell on the "rubbish body" of the ammonite. 

[elegantoceras]

Hi Andreas, thanks for looking at this. I took it back another inch this afternoon. I have arrowed the the last pattern on the shell. Is that where  you mean?

 

The reverse of the shell is not preserved but the dorsal aspect is all there..I am dubious about the centre and have nothing to compare to .

 

I think I may have to balance how far to go dependant on the time I have!!

 

Still my wife is happy as she says its going to keep me busy for some time!

 

[Ludwigia]

That's right. I wouldn't take any more off now. Can you show a direct view of the keel and the reverse side please, despite the poor preservation? It looks like the whorl width is not that great, which might make it a M. cf. jaquoti or M. verus. Did you dig it directly out of a particular horizon or was it in a stray block?

[elegantoceras]

Hi Ludwigia, we were guest in a quarry. Large amount of rock just dug out from in situ, was in a larger block that I knocked down to get home.The body chamber was probably about as half as big again but had to leave some behind.Don;t often see any calcite in this quarry so thought it may be worth exploring for prep. Not sure what to do with the centre as I have gone thru these before into a cavity .

[andreas]

Looks good so far. It depends on you to stop now or not. I would do like Roger said. For the center(the umbilicus) just google Macrocephalites. There are enough pics in the net where you can see a preped Umbilicus to get a feeling for it.

And yes your arrow marks the end of the Bodychamber.

[elegantoceras]

Thanks for your replies Andreas and Ludwigia . In the centre there is a small bivalve who has been resident for some years and I haven't the heart to separate them.

 

I will grind the matrix at the weekend to tidy it up,then i'm done. Do you think it is M. verus?

 

[Ludwigia]

3 hours ago, elegantoceras said:

Do you think it is M. verus?

 

 

Possible, but I still need direct views of the venter/keel, one towards the mouth aperture and one from the opposite side in order to be able to determine the whorl breadth.

[elegantoceras]

Heres trying for pictures of the keel.Cheers.

[RJB]

I would say, "nicely done". 

 

RB

[elegantoceras]

Thank you RB. It's quite a big 'un . Waiting for my new grinder to tidy up the mouth.

 

[Ludwigia]

Thanks for the photos. I'd venture the guess that it's either M. jacquoti or M. verus. They are almost identical and the only way to be absolutely sure which is which is to know exactly which horizon it was found in. They both occur in the keppleri zone, but the former in the keppleri horizon and the latter in the suevicum. There are transitional forms in between in the quenstedti horizon. If you don't remember exactly which horizon it was found in then you could probably get away with calling it Macrocephalites jaquoti/verus Transitional form.

[elegantoceras]

Thanks so much for your trouble and information Roger. I can't help any further with the horizon,i'm no geologist i'm afraid, just a crazy collector. I think from googling M verus  is pretty good.The quarry breaks out the hard layers then puts it all through a crusher, most of the fossils are obliterated. I have visited three times now(we go in once a year with a geology group) ,this is the first time I have found  one with reasonable ornimentation. Sadly I think they may flood the quarry by next year,still they have to start digging somewhere else then!!

[Ludwigia]

On 11.5.2017 at 0:03 AM, elegantoceras said:

Sadly I think they may flood the quarry by next year,still they have to start digging somewhere else then!!

 

Pity. That's happening more and more in the western world now and that "elsewhere" you mentioned is usually somewhere in the 3rd world or out in the boondocks.