Found in the drawer – Tiltoniceras

Tiltoniceras antiquum (WRIGHT, 1882), 4.5 cm diameter

Tiltoniceras antiquum (WRIGHT, 1882), 4.5 cm diameter

It´s more than 20 years ago that I found the above ammonite, and it has remained the only 3D preserved Yorkshire specimen of this species so far in my collection.
It was found, probably in a semicelatum subzone nodule, at Runswick Bay. “Probably”, because nothing much remained of the original nodule…

At that time, we used to sit down on the terrace of our then accommodation in nice weather and reduce weight on the fossils as much as we could, we were coming by plane to London and took trains and buses to Yorkshire, so luggage weight was restricted, both by the airline and the amount of rock we could carry…

The ammonite must have been damaged by splitting the nodule already and I obviously tried to extract the better preserved side by separating it from it´s heavy nodule matrix using only small chisels and hammer – this is why this ammonite ended being like it is today – a rather damaged specimen.

I must have also taken it for an Eleganticeras, because some years later when I was re-organizing my drawers I looked at my Eleganticeras specimen again
and found there was one that somehow did look different from a same sized Eleganticeras.

The umbilicus is the shell element that clearly distinguishes Eleganticeras and Tiltoniceras :
While Eleganticeras has an angled umbilical edge, Tiltoniceras has a smoothly rounded umbilical edge.

Comparison of umbilicus of approximately same sized Tiltoniceras (left) and Eleganticeras (right)

Comparison of umbilicus of approximately same sized Tiltoniceras (left) and Eleganticeras (right)

There are some beds on the Yorkshire coast where crushed, flattened Tiltoniceras are quite abundant, but I find it quite difficult to distinguish flattened Tiltoniceras from flattened Eleganticeras :

Bed with crushed Tiltoniceras antiquum, diameter of largest ammonite 4.5 cm

Bed with crushed Tiltoniceras antiquum, diameter of largest ammonite 4.5 cm

It is only quite clear when you find them with Dactylioceras semicelatum in the same bed, like in a photograph I´ve shown in an earlier post :

Flattened D. semicelatum and Tiltoniceras

Flattened D. semicelatum and Tiltoniceras

Of course with hindsight, the ammonite would have deserved a much better preparation.
Today I´d probably recognize it for what it is and with much better tools and a lot more experience attempt a transfer preparation of the broken off pieces,
and display it on the half nodule, keeping it in it´s natural matrix. But – it is what it is, a product of what I knew and could do then.

AndyS

Previous Post
Leave a comment

2 Comments

  1. Mike F

     /  April 21, 2014

    Andy,

    Interesting. Thanks for sharing. That was effectively in a semi nodule? Never seen a hint of one of those in semi noduleas I’ve worked through – and that’s a fair few!

    Cheers,

    Mike F

    Reply
    • Mike,
      Yes it must have been – though the matrix is a bit darker than the usual semicelatum nodules.

      All the best,
      Andy

      Reply

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: