Water Ripples And If Not, What Is It From?

[Sydneylh]

So I came across this while hiking along a reservoir (Polk county, Iowa) a few days ago. I'm not sure if they are any type of fossil or imprint of something or possibly caused from some type of water movement cycle? Any help would be great! Oh, the rock is about the size of my hand...Thanks!

- Syd

Edited March 22, 2015 by Sydneylh

[Auspex]

They are surely something...what is their size?

[Sydneylh]

They are surely something...what is their size?

here is an image of the rock with a standard size sharpie marker.

[Auspex]

Here's a wild guess:

A weathered section through a straight-shelled cephalopod.

The ridges could be the chamber septa, the solid red lines mark the edges of the tapering shell, and the dotted line is the siphuncle. Maybe. That's just what struck me while trying to make something of it.

[Sydneylh]

Here's a wild guess:

A weathered section through a straight-shelled cephalopod.

~.jpg

The ridges could be the chamber septa, the solid red lines mark the edges of the tapering shell, and the dotted line is the siphuncle. Maybe. That's just what struck me while trying to make something of it.

That's a pretty great guess! Now I'm even more curious to find out what it could be!

[Jeffrey P]

At first I was thinking maybe part of a trilobite thorax, but now I'm leaning towards a straight-shelled nautiloid (cephalopod). Either way, something new for the collection. Congrats!

[Sydneylh]

I cam across this image of a trilobite. Do you think mine resembles some of that?

[bone digger]

Or possibly the imprint of some Brachiopods?

[JimB88]

I believe Auspex is right on; its a straight shelled cephalopod impression. A good find in any case!

[bone digger]

Here is a site that lists some fossil localities in Iowa and what is found there. Maybe it will help you identify your fossil or help you find more!

http://fossilsites.com/STATES/IA.HTM