Heteromorphs

[hallucigenia]

How little is that little critter, Kevin? Did you take it with a macro lens or a light microscope? (Not that I can ID it anyhow, but I'm curious.)

 

[Architeuthoceras]

It is about 1.5mm long. I took the picture through the eyepiece of my microscope.

I don't know if it is possible to ID the thing, there are no matching adult fossils found in these beds. My first guess would be Allocrioceras, just because of the round whorl section, and they have been found in older and younger beds.

Another pic that shows the shape of the apertural end a little better.

 

[Terri]

Is it from a Cretaceous bed,was it found in Utah? Not that I could id it either, but intriguing nontheless.

 

[Architeuthoceras]

Yes, these are Cretaceous, from the upper Turonian Scaphites whitfieldi Zone (time scale below) in the Mancos Shale of east central Utah. I have found Allocrioceras in the Cenomanian Sciponoceras gracile Zone and in the Coniacian Scaphites preventricosus Zone.

This thread shows a few more small fossils from this locality. In the pic that shows the area, the red rock in the background is in Arches National Park.

 

[nanoteuthis]

Wow, some of those look like shofars!

 

[Architeuthoceras]

Maybe Shofarites

 

[Hajar]

I made a start on a gallery of heteromorphs.

 

[Architeuthoceras]

Some nice ammonites there.

 

[Terri]

Beautiful and informative collection Hajar, looking forward to seeing more!

 

[Hajar]

Thanks very much Terri. I've just been reading about the Aegocrioceras faunas from Yorkshire and northern Germany. We visited the Speeton location on the Yorkshire coast briefly this summer and found many belemnites and several ammonites, mostly not very well preserved. The Speeton Clay is the dark outcrop on the right hand side of the photo, with the overlying chalk forming the cliffs in the distance (famous for huge numbers of seabirds including gannets, razorbills and puffins).

 

[Terri]

Sounds like a fun time, looks like the young one has already developed a good eye!

 

[Hajar]

Yes, kids have sharp eyes and are closer to the ground!

Here's something lovely. A Middle Jurassic heteromorph, Spiroceras, from France. It's just 2 cm across, but silicified and etched free from its matrix.

 

[DWhatley]

Hajar,
Is this one you found? Is it free from the rock through natural wear or does etched free mean cleaned by hand? Sorry, very novice at looking a fossils.

 

[Terri]

Beautiful! A very nice addition to your collection. How something that small can be freed from the matrix without damage is amazing to me. I am going to try to spend some time this winter learning and attempting fossil preparation, I'll have to acquire some proper tools first!

 

[Architeuthoceras]

Just to answer for Hajar because I can't wait

Silicified fossils have been replaced with silica (basically quartz), so they can be etched with dilute acid, commonly Hydrochloric Acid, this dissolves the Calcium carbonate matrix but leaves the fossil intact.

A very beautiful fossil Hajar