Please help me identity

[ToniaM]

I was on a walk and this rock had broken away from the bluff and was on the trail. Does anyone know what the fossil is?

[Darktooth]

Well you have a couple different fossils on your specimen. The long straight one that tapers down to the end is a nautiloid. At the end of the nautiloid appears to be a internal mold of a gastropod. Above the gastropods there is another circular object, but not sure what that is.

[rocket]

1 hour ago, Darktooth said:

 Above the gastropods there is another circular object, but not sure what that is.

 I am sure it is a gastropode, too. A single whorl

[Darktooth]

4 hours ago, rocket said:

 I am sure it is a gastropode, too. A single whorl

I was thinking the same, but wasn't 100% sure.

[minnbuckeye]

Nice piece of matrix!! Looks like rocks from the Galena / Ordovician period (holey limestone). So the bluffs mentioned  were along or close to the Mississippi? @Darktooth points out a large single whirl of a gastropod. Below it is a second gastropod split in half 3-4 oval structures lined up. Both are likely partial Hormatoma  gastropods. To identify the cephalopod, look at the end of it and see if you can identify a siphuncle, a round tube these creatures used to adjust their buoyancy. It should look round if present and helps to identify species depending on size and location. 

  

 Mike

[ToniaM]

Thank you all. Yes MinnBuckeye Mississippi at Dubuque.