New Mexico Mud Fossil???

[dana hausen]

I discovered this rock at the bottom of a dried arroyo in New Mexico this past June.

I'm thinking it is a mud fossil. What do you think?

 

[hadrosauridae]

Not a fossil, its a septarian nodule.

[tombk]

Welcome to The Fossil Forum. That's a cool-looking rock. The rock as a whole does not appear to be a fossil, and I don't see any clear fossils on the outside of the rock. In this middle picture, there may be a fossil of a small shell from a type of creature known as a brachiopod (think of a modern-day clam to picture one, although they are not related). I can't be sure from the picture though. If you'd like, you can take another photo of that part of the rock with a bit more light, and we may be able to see whether there's something there or not.

[abyssunder]

It's a very nice septarian nodule/concretion!

[Fossildude19]

I agree, this is a septarian nodule with fossils on the inside. 

Not even sure what a "mud fossil" is, though.  

I guess, technically, since the fossils appear to be of marine origin, perhaps the matrix surrounding them may have been mud at one time.  

[dana hausen]

Wow! You all are AWESOME! Thanks so much for sharing your expertise! I did GOOGLE septarian nodules and found they are " fossilized mud bubbles that formed between 50 and 70 million years ago.  Composed of calcite, aragonite, and are coated in limestone, they form in air bubbles which create crystal pockets." I was happy to find several photos similar to my own. My earlier searches led me to dinosaur eggs....which didn't look much like my rock. It sure helped knowing the right search words to enter. Thanks, again!!!!