There's gold in them there nodules!


Jun 25, 2004
Hi All

Had another wander along the Holderness coast a couple of weeks ago and found an obvious upper lias nodule eroding out of the boulder clay that makes up the cliffs on that section. Gave it a tap and voila! a rather nice specimen of Dactylioceras tenuicostatum preserved largely in Pyrite. This particular beastie has had a fairly adventurous post death existence having remained buried for 180 million years or so, then being scraped out of the ground by a passing glacier, carried across country for a fair few miles before being buried again for a few more thousand years before finally being uncovered by the sea again - and then just when it was about to return to its ancestral home it gets whacked by a hammer and put on a shelf! It just shows you never know what the world will have in store for you.



  • conv_302187.jpg
    96.2 KB · Views: 158
Aye, it is a nice one. They are quite often pyritic to some degree but this one was one of the most metallic I've seen. Easy to prep aswell - a few taps with the hammer to show it was there then about 30 minutes with the airpen and a quick clean up using my mates air abrasive. The back of the nodule is covered in Glacial striations aswell.

Fine & dandy Andy !
I've a pair of Cardioceras I'm slowly rebuilding after bouncing down the cliff at Pakefield, Suffolk which have taken a very similar journey to yours & now live in an icecream tub in France awaiting more of my attention.

"Fools Gold"

I wonder why we dont have many fossils around these parts replaced with Pyrite? All I see is sometimes a clump of square crystals, I think its Goethite (a replacement of the original Pyrite) and usually attached to the fossil, not replacing it. :sad: It sure makes a good lookin fossil. Well at least I dont have to worry about any of my fossils getting that pyrite disease :wink:
Luckily for me the Yorkshire coast pyrite seems pretty stable, no deterioration on any of the finds even after 10 years or so. Theres a lot of pyrite in the beds around there - particularly the Jet Rock which has beds of pyrite skinned nodules which look great when polished up (aswell as having their own range of ammonites within!).


Even the Jet rock pyrite nodules eventually start to decay - I have some from about 16 years ago that now start. I would think that polishing even accelerates the decay unless you really seal the surface with some air- and water tight varnish.

Hi Andy - nice to hear from you again.

So, I've got that to look forward to then. Never mind. This one has had a light coat of matt varnish diluted in white spirit.

Had a look over Robin Hoods Bay again last week which was quite successful. Androgynoceras, Gagaticeras, Amaltheus, Oxynoticeras - I think we'd found examples of 10 genera by the end of the day though few were what I'd call presentable. Found as yet unidentified spiny ammonite in situ in an Obtusum zone nodule. Will post a picture later (its not a great example of whatever it is though).

All the best

Here is the mystery Robin Hoods Bay (lower Lias) ammonite - any suggestions gratefully accepted :smile:

Andy (not S)


  • conv_288002.jpg
    67 KB · Views: 163

This very much looks like one of the rarer Ammonites from the obtusum zone in Robin Hoods Bay - Xipheroceras sp., from the inner whorls I'd say X. ziphus, but the outer whorls don't really match, unless it is rather big - how big is it ?

I've only ever found 2 Xipheroceras in 16 years in Robin Hoods Bay, one cluster of 4 small max. 1.5 " X. ziphus, one 3" X. dudressieri.
In the small cluster there is one with complete spines, it itches me to finally prep it using air abrasive, maybe during the weekend, I'll post a picture when it's done...

Spectacular ammonite there Andy. That's got to be as good as they come from Holderness, surely. Great find indeed.

Most of the ammonites I have found from the local clays are heavily pyritised. I always give them a coat of varnish and, touch wood, this has worked to date. Whether I can say the same in five or ten years time we'll have to see.
Hi all

AndyS - the RHB beastie is about 7cm (I'm at work so am estimating from memory but it won't be far out). Was found in a nodule cropping out in one of the scars not far from the waterfall over towards the Ravenscar end.

Phil - the tenui is about 9cm and I was quite pleased with it. Its not the best from there by a long way though!. Had a slightly hair raising time getting this one. Was strolling along with the brain tuned in to nodules when I realised I was standing only 3ft from a bomb :shock: (there's a firing range off shore and things frequently get washed up). About 2ft long with fins and very rusty. Looked around and there were about 50 of them lying all around. Its a public beach and has plenty of people walking and fishing along it and you don't hear of many exploding holiday makers so I'm assuming these things are fairly inert but I wasn't taking any chances and left the area sharpish.

Was strolling along with the brain tuned in to nodules when I realised I was standing only 3ft from a bomb

Good lord, Andy. I had no idea ammonite hunting could be so dangerous! Have you considered piling those things up and using them to blast away a huge section of cliff?

Xtreme Palaeontology?

Here comes promised Xipheroceras ziphus from the lower lias of Robin Hoods Bay (size is about 1.5 " / 4 cm) :

The first picture shows the cluster of 2 Xipheroceras, with the one in the front the spines have all broken off during cracking of the nodule (and I did not know what it was then, otherwise I'd have taken the negative...), in the background you can see the venter of the second one with some of the spines.
The second picture shows one of the spines from the other side of the ammonite, the length of that spine is about 7 mm !

Must have been a nasty prey to chew on for those jurassic predators !



  • conv_288057.jpg
    117.2 KB · Views: 107
  • conv_288058.jpg
    120.3 KB · Views: 129
Sponsor Banner
please support our sponsor
advertise on TONMO

Shop Amazon

Shop Amazon
Shop Amazon; support TONMO!
Shop Amazon
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.