ID of goniatites / ammonoids

[fossils.ie]

 

The Namurian cyclothems in West Clare, Ireland originate in an environment of delta systems which deposited sediments in an offshore basin (Clare Basin) and are referred to as the Central Clare Group.

 

There are five cyclothems comprising marine bands (conventionally considered to form the ‘base’ of each cyclothem) and upwards coarsening fine-grained and sandstone sediments. The five cyclothems are named (from oldest to youngest): Tullig, Kilkee, Doonlicky, Cyclothem IV, and Cyclothem V. The marine bands contain - among other fossils - index fossils in the form of ammonoids (goniatites). These index fossils are used to determine the stratigraphy of the cyclothems. 

 

Central Clare Group marine bands and goniatite index species (youngest at top)

Cyclothem V top - R2c1 - Reticuloceras superbilingue alternatively Bilinguites superbilinguis (Bisat, 1924)

Cyclothem V base - R2b - Reticuloceras wrighti alternatively Bilinguites metabilinguis 

Cyclothem IV base - R2 - Reticuloceras bilingue alternatively Bilinguites bilinguis (Salter, 1864)

Doonlicky base - R1c - Reticuloceras reticulatum

Kilkee base - R1b3 - Reticuloceras stubblefieldi alternatively Phillipsoceras stubblefieldi

Tullig base - R1b2 - Reticuloceras nodosum

 

My problem is the differentiation between these goniatite species in the field. Some of them look quite similar - to me - and in addition, they are preserved as very compressed, often crushed shells. At one location, they are firmly incorporated into concretions which appear to have dried out at some time, showing polygonal cracks filled with calcite; very handsome but even more difficult to identify.

 

Under this topic, I have grouped images of goniatites by location and added information regarding the goniatite species recorded on the Geological Survey Ireland Spatial Resources website for each location. 

 

Any help with identification is greatly appreciated!

 

So the first batch of images from Seafield beach, near Quilty village, County Clare, Ireland is in my collection 'ID of goniatites / ammonoids - Seafield'.

The Geological Survey Ireland Spatial Resources website records Reticuloceras superbilingue, Reticuloceras bilingue and Reticuloceras stubblefieldi  for this location.

But which is which in the images?

[Fossildude19]

1 hour ago, fossils.ie said:

Under this topic, I have grouped images of goniatites by location and added information regarding the goniatite species recorded on the Geological Survey Ireland Spatial Resources website for each location. 

I am not seeing any images.  

Don't know if you've seen this Researchgate article?

Another potentially helpful website. 

[westcoast]

I can tell you that species identification of this material is not easy, as you say most are crushed and also species are in need of revision. Can I ask what work you are doing in this area, which is my back garden . Feel free to PM me.

[fossils.ie]

11 hours ago, Fossildude19 said:

I am not seeing any images.  

Don't know if you've seen this Researchgate article?

Another potentially helpful website. 

Hi Tim,

thank you for your response and the initial welcome message as well! 

Having posted my first message last night, I found I couldn't upload any images as the options were greyed-out. Maybe the website was too busy. I'll try again.

I'll also check out the resources you mentioned.

All the best,

Jutta (fossils.ie)

[fossils.ie]

13 hours ago, fossils.ie said:

 

 

The Namurian cyclothems in West Clare, Ireland originate in an environment of delta systems which deposited sediments in an offshore basin (Clare Basin) and are referred to as the Central Clare Group.

 

There are five cyclothems comprising marine bands (conventionally considered to form the ‘base’ of each cyclothem) and upwards coarsening fine-grained and sandstone sediments. The five cyclothems are named (from oldest to youngest): Tullig, Kilkee, Doonlicky, Cyclothem IV, and Cyclothem V. The marine bands contain - among other fossils - index fossils in the form of ammonoids (goniatites). These index fossils are used to determine the stratigraphy of the cyclothems. 

 

Central Clare Group marine bands and goniatite index species (youngest at top)

Cyclothem V top - R2c1 - Reticuloceras superbilingue alternatively Bilinguites superbilinguis (Bisat, 1924)

Cyclothem V base - R2b - Reticuloceras wrighti alternatively Bilinguites metabilinguis 

Cyclothem IV base - R2 - Reticuloceras bilingue alternatively Bilinguites bilinguis (Salter, 1864)

Doonlicky base - R1c - Reticuloceras reticulatum

Kilkee base - R1b3 - Reticuloceras stubblefieldi alternatively Phillipsoceras stubblefieldi

Tullig base - R1b2 - Reticuloceras nodosum

 

My problem is the differentiation between these goniatite species in the field. Some of them look quite similar - to me - and in addition, they are preserved as very compressed, often crushed shells. At one location, they are firmly incorporated into concretions which appear to have dried out at some time, showing polygonal cracks filled with calcite; very handsome but even more difficult to identify.

 

Under this topic, I have grouped images of goniatites by location and added information regarding the goniatite species recorded on the Geological Survey Ireland Spatial Resources website for each location. 

 

Any help with identification is greatly appreciated!

 

So the first batch of images from Seafield beach, near Quilty village, County Clare, Ireland is in my collection 'ID of goniatites / ammonoids - Seafield'.

The Geological Survey Ireland Spatial Resources website records Reticuloceras superbilingue, Reticuloceras bilingue and Reticuloceras stubblefieldi  for this location.

But which is which in the images?

 

[Shamalama]

Crushed or not, those are nice looking fossils. I hope you are able to ID them to species level.