Husband found this fossil in a load of gravel

[jwhittecar]

My husband found this fossil in a load of gravel that was delivered to our home here in northwest Nebraska. Can't say for sure, but gravel is probably from this area or maybe southwest South Dakota.

The fossil is 5 1/2" along outside curve and 1 3/8" in diameter. You can see in the photos light spots and those are very shiny, almost look like glass. The color in photos isn't accurate, the color is tan.

Sitting on the knobs it looks like a giant caterpillar to me.

 

[Ophiolite]

It appears to be a fragment of an ammonite. The ammonites were chambered creatures which added new chambers in a spiral pattern as they grew. The abandoned chambers were used to control floatation by varying gas pressure within them. In most ammonites the later chambers overlay the earlier ones. Some forms did not overlap - evolute rather than involute - and this appears to be such an example.

I'm going to take a wild guess - based on dimly remembered data from five decades ago - that this is Triassic in age. Unfortunately the real diagnostic feature is the suture line between chambers and this is not visible in your specimen.

 

[Huyen401]

Wow, what an amazing find! It's always so exciting to come across something like this unexpectedly. I'm not an expert in fossils, but I did a bit of research and it looks like your husband may have found a fossilized ammonite. Ammonites were marine creatures that lived during the Jurassic and Cretaceous periods, and they are known for their distinctive spiral-shaped shells. The shiny spots you mentioned are probably the remnants of the shell's inner layer, which was made of a pearly material called nacre. The color of the fossil may have changed over time due to the minerals in the gravel it was found in. Regardless, it's a beautiful specimen and I'm sure it holds a lot of history. Thanks for sharing it with us!