Prepping a 1412 gram/3.1 lb Outer Whorl Section of a Prionocyclus macombi Ammonite

[SPrice]

After a fair amount of research which paid off quite well for a beginner, I finally began to mesh some of the "bookworm" experience with the "on site blundering around in the desert until I got lucky"  experience.  The research said - large ammonites in this location.  Okay. Many trips later, I suppose 6 inch diameter ammonites are considered Large.  Found some,  check. 

 

Another fossil collector's  blog said the same thing so I went there.  It just happened to be on the other side of the big ditch I was previously hunting in. Okay, the ditch was 20 plus miles wide with the Morrison Formation filling the ditch all the way to the other side. Turned out this opinion of what equates to a large ammonite was more in line with what I was thinking. 10, 12, 15, 20 inch diameter ammos sure fit the bill to me. When it takes two to carry one to their vehicle...yeah...you have a BIG ammonite. 

 

For me even the partials were amazing when just 3 or 4 chambers of an outer whorl were found. Doesn't take much to realize this 3 pound whorl section belonged  to 350 to 500 mm diameter squid in a snail shell!  Kinda like finding a Meg tooth or raptor claw...one definitely envisions the original owner's size. 

 

This is another chemical prep after gluing the loose parts securely. I used muriatic acid and a soft bristled toothbrush with a tub of water to rinse after each pass. This whorl section had been previously dug some years ago, IMO, and left behind. It has a few small lichen patches on the "back" side which I left as is. The largest lichen patch is 1 CM wide which equates to 1 mm a year's growth over 10 years of sunlight exposed rock. More or less. No other connecting parts were nearby when I collected it.  

 

I made one pass, rinsed, then a second pass with fresh acid followed by a rinse, repeat until the stopping point.

 

As found.

 

 

First pass.

 

 

 

Second pass and rinse.

 

 

Third pass and rinse.

 

 

Final pass, rinse and stopping point. I was looking for some color contrast from before and after...or rather...coated with calcite and coating removed down to the "chocolate" with some areas still showing the calcite coating. 

 

 

Top view of the keel area.

 

 

Backside with lichen patches showing.  

 

 

Drying after final rinse and inspection. 

 

 

Dry the next day.

 

 

 

 Freshly  applied Paraloid coating.  

 

 

It cured out slightly less shiny except for the smoothest spots.

 

 

 

Besides just liking these partial whorls of large ammonites, It's good practice for these guys awaiting preparation.  The one on the right is a concretion of over 100#/45 + kg.  The bucket on the left side has a 56 pound concretion with a 10-12 inch ammo in it.

 

So the research boiled down to who considers what's big and what's REALLY BIG. I like them all but it was nice to find some that make me think I found something " DINOSAUR big" and not snail shell big. 

 

 

 

Edited May 4 by SPrice

[Alex S.]

That's awesome @SPrice glad to see your research is paying off looks like you have some fun preps ahead of you.

[SPrice]

11 minutes ago, Alex S. said:

That's awesome @SPrice glad to see your research is paying off looks like you have some fun preps ahead of you.

 

 

A couple from Price shared their spot with me willingly and I assisted carrying some of their bigger finds to the minivan. I showed them what inchnofossils were and they went crazy finding and collecting a few very nice samples. The gal showed me a phone pic of the biggest and best looking Utah Ammonite I've seen and then the other shoe dropped.

 

When they got home with it and kind of dropped it in their yard ( that's where they put them ) ....it fell apart like a 500 piece, 3D puzzle. I just agonized over that loss. It was pristine - perfect - one moment ...gone the next.  I shared with them to always carry super glue and squirt it generously into all the cracks. Or wrap it with foil and tape and bubble wrap and a blanket, next time.

 

We had a great time and they showed me where to look for some of the surface finds I collected. 

Edited May 4 by SPrice

[Alex S.]

That's a heart breaker. Luckily they met you and can change there ways.