Strange fossil?

[x354harox]

I have not a clue what this is? Anyone?? It’s a square pocket with what looks like a spine of I don’t know what. Any thoughts??

[jpc]

crinoid stem impressions

 

[Fossildude19]

Actually, the smaller one is a cast of a crinoid stem lumen. 

[DPS Ammonite]

It looks like you have exterior and interior molds (impressions) of a crinoid stem in a piece of Redwall Formation chert which can be found near the Diamond Rim/Point area in Gila County, Arizona. Chert nodules form around calcitic fossil remains. As the nodules weather over thousands of years the calcite dissolves leaving molds. If you crack open larger and newly exposed chert nodules you often can still see the calcitic fossils.
 

Keep looking in Redwall chert nodules and you may find trilobites and blastoid/crinoid heads.

[Mark Kmiecik]

Yup, crinoids. Sometimes the way they are preserved may resemble fish backbones. They are very common marine fossils. The ones you see on the surface are worn/weathered. There may be more inside the rock in better condition. You can crack the rock open and check, but make sure to wear eye protection if you do. It's a commonly found fossil and you should be able to find more where that one came from, so if you ruin it you should be able to easily find another. Google it and look at the images. The part you see on your specimen are small sections of the stalk. The images will show you the whole animal, and the drawings will define it's parts. (Yes, it's an animal, not a plant)