Wyoming, turritella (Edit: Elimia Tenera) , Morrison Formation

[Ron Kelley]

Mike has inspired me to post one of my fossils too (Actually many fossils in one slab). I bought this slab on ebay. It is rough and I probably should put a polish on it.

[Hoss]

Pretty awesome looking fossil Ron

[2ndoldman]

That is a nice fossil and great picture Ron.
How close to real size is this picture?

[Ron Kelley]

Hey Bruce, The picture is only part of the slab. The fossils are a little bigger than they appear on my monitor. Of course the picture will be many different sizes on different screens. The Turritella (Edit: Elimia Tenera) fossils in this slab are very close to one inch long.

[2ndoldman]

Thank you Ron. It was impossible to tell if this was a macro closeup or more realistic in actual size.

[painshill]

Nice, Ron.

I have some of that material too and for a long time I believed it to be a Turritella species since almost everyone refers to it as that. However, I now know that it isn't. The shells are from the freshwater snail species Elimia tenera, which has a very similar shape.

[Ron Kelley]

Hey Roger, Thanks for the info. I will edit my records. I Googled both and they do look very similar. I did just a little reading and found that these fossils are from the late Jurassic 161.2 to 145.5 million years ago. Time of the dinosaurs. Is that information accurate?

[painshill]

No! See below.

[painshill]

This stuff has been touted by lapidary/rockhound sellers for years under the erroneous title of “turritella agate”. The silicified shells are actually Elimia tenera in a matrix of chalcedony. The problem is that the sellers are not palaeontologists, but the misinformation has spread a long way.

The Morrison Formation is indeed Upper Jurassic (156.3–146.8 million years) and represents terrestrial material from mountain drainage basins carried eastwards by streams and rivers to be deposited in swampy lowlands, lakes, river channels and floodplains centred around Wyoming, Colorado and beyond. Turritella have been around since the Cretaceous, immediately following the Jurassic (so there could be an overlap into the Upper Jurassic), but they’re exclusively marine organisms and the Morrison Formation doesn’t have marine deposits.

Conversely, although Elimia is a freshwater organism, it couldn’t have come from the Morrison Formation because it’s Eocene in age (generally 51-46 million years and therefore post-dinosaur) and certainly not reported as far back as the Jurassic or Cretaceous.

The shells of Elimia are distinguishable from Turritella by being generally shorter and wider (Turritella gets well beyond an inch and sometimes up to 6 inches) but especially in having an axial as well as spiral sculpture on the shell. You can see that on the shell I have highlighted from your specimen below:


What you have is almost certainly from the Laney Member of the Green River Formation, which represents Eocene deposits from freshwater lake environments that include extensive occurrences of silicified Elimia shells. Although very different in age and having no palaeontological relationship to the Morrison formation, there are places where the two formations are in close proximity. The Green River Formation runs along the course of the present-day Green River through Colorado, Wyoming and Utah with the Morrison Formation consistently present from the Green River in Utah all the way to the Utah-Colorado border.

Your eBay seller has no real experience in palaeontology or stratigraphy and is probably repeating stuff he found on the internet (in good faith). That doesn’t take anything away from the quality of the specimen itself of course.

[Ron Kelley]

Thanks Again Roger, There is a lot of misinformation on the net. Your post explains a lot. Thanks Man

[lukecreekwalker]

Based on my very limited fossil knowledge...I know of gastropods and ammonites. I'm assuming this is neither. I know its a marine animal though! Pretty neat stuff Ron. I was actually trying to find your trilobite collection you posted a while back I remember you had some great ones. Do you have any fish or fern fossils you could post? Those are 2 I am going to buy next I think. Probably retire after that lol

[Ron Kelley]

Hey Mike, Roger explained that Elimia Tenera was a freshwater snail. I don't have any trilobite fossils: I think Charlie has a good collection. I do have a nice fern fossil.

[lukecreekwalker]

That explains why I couldn't find the posts lol...ok I will look. Thanks again and if you have a fern fossil I'd love to see it. I found a small piece of one in the creek the other day and I just want a full one now.

[painshill]

This is NOT a marine animal. It's a freshwater snail. A pond snail if you like.

Both Turritella and Elimia are gastropod molluscs but they are respectively marine and freshwater. The term gastropod includes all snail-like creatures (marine, freshwater or land) which have a coiled or conical single-part shell that is large enough for the soft parts of the animal to withdraw into, plus limpets (where the shell acts as a cover) and slugs (which don't have a shell). It doesn't include molluscs with two halves to their shell such as clams, oysters and scallops. Those are "bivalves".

Ammonites were also molluscs but they were cephalopods not gastropods. In the same family as squid, octopus and cuttlefish.

[painshill]

If all you want is a nicely-preserved fish with good detail at a reasonable price, I would suggest you look for Knightia specimens from the Green River, or Jianghanichthys (also known as Osteohilus) from China. Recently, a new location for these was discovered in Viet-Nam and for a while the price has dropped even more.

Here’s a couple of mine. The first is a Green River Knightia (these are usually Knightia alta) belonging to the same family as herring and sardines, although it’s a freshwater fish. The second is a Chinese Jianghanichthys (these are usually Jianghanichthys hubeiensis) belonging to the carp family and also freshwater. The Chinese know them as Chan Han Fish.




Nice fern fossils are also plentiful and cheap. Look for a Lycopteris on a good matrix or in a split nodule. Here’s a couple of British ones, but there are lots of locations (generally from areas where there are coal mines):




If you shop around you should be able to find any of these for under $10

As for trilobites, the price varies enormously according to size, species and location. My very strong advice for a novice would be not to buy a Moroccan specimen from an eBay vendor. There are so many fakes around. Use a reputable dealer if possible. Here’s a bunch of splendid Moroccan fakes awaiting some unsuspecting buyer:

[lukecreekwalker]

Thank you so much Roger. I was looking at Moroccan ones on eBay. You saved my bum. I saw those green river ones and didn't know if they were real on eBay. One seems pricier than others. Priscacara...man it's sweet though. I will check out that species of ferns for sure

[painshill]

You're welcome. I don't think anyone is faking Green River fish in the same way as for Moroccan trilobites but they may be "enhanced". Sometimes they may be stained to improve the contrast between fish and matrix for example. Personally, I have no objection to this and I don't object to the application of sealants to protect delicate fossils. Painting is a different matter, particularly since it introduces a temptation to paint in additional details missing from the fossil itself. Yes, the price will be size and species dependent. Priscacara is from the perch family and is both generally a larger fish as well as a less frequent find than Knightia. Hence the higher price. There is an eBay buyer guide for Green River fish here:

http://www.ebay.co.uk/gds/Green-River-Fish-Explained-Natural-Stained-Sealed-or-Painted-/10000000205389076/g.html

There are of course authentic Moroccan trilobites on eBay but my advice would still be that a novice should avoid all eBay Moroccan trilobites until they have enough experience to recognise the tell-tale signs of fakery (and the seller offers a refund guarantee). Why take the chance? There are plenty of nice trilobites from other locations which don't carry the same risk of fraud. Another tip I would offer is to look for trilobites which have been "split" out of the matrix where both the positive and negative impressions are supplied (as opposed to a standalone fossil which has been prepped out of its matrix using scribing tools to expose it). It's extremely difficult to fake a matching positive/negative pair.

[Ron Kelley]

WOW Roger, That's some great detail on your fish fossils. Thanks for showing them.

[Havenhunter]

Older than Samuel Clemens. 😋

[Kyflintguy]

Some nice fossils in this thread! Thanks for sharing them and the info guys!

[Scorpion68]

Awesome fossils. Those trilobites would have fooled me for sure. Ya know - we have several slate mining sites around my area and I've always heard that they find fossils in slate. Hum - I wonder if I should get permission to do some hunting in their slag piles?? This has been a very educational post. Thanks ya'll. ...Chuck

[Scorpion68]

Slate quarries would be a better description than mines - I think.

[Kyflintguy]

Thats a good idea Chuck, those places can be very productive. As a child I use to hike up the hill from our home at the time to visit a large piece of shale or slate that had rolled down the mountain from a strip mining operation. The chunk was roughly the size of a VW and broke apart in nice flat vertical layers. I found hundreds of "snails" and other crinoid like fossils... I would pluck away for hrs at a time pretending to be a paleontologist... I say give it a go! Just be careful around loose and unstable face cuts, those can be bad news!

[SDhunter]

That would look nice polished