Found this in a Mazon creek Nodule, please help ID

[Thomas J. Corcoran]

[caldigger]

Kindly give us some in focus pictures with a scaled ruler beside it for size reference.

[Thomas J. Corcoran]

24 minutes ago, caldigger said:

Kindly give us some in focus pictures with a scaled ruler beside it for size reference.

Here you go

[Thomas J. Corcoran]

[caldigger]

A nodule within a nodule? 

 

@Nimravis hey Ralph, seen anything like this before in those billions of ones you've opened?

[Thomas J. Corcoran]

3 minutes ago, caldigger said:

A nodule within a nodule? 

 

@Nimravis hey Ralph, seen anything like this before in those billions of ones you've opened?

Noduleception!

[connorp]

Often times nodules will have an outer layer that comes off. Sometimes it will be thin and flaky, but I’ve had a couple nodules that look like they split, but it turns out to just split along the outer layer. A good 1/2” thick layer come cleanly off once, kind of like those Russian doll things. 

[Rob Russell]

Yes, you’ve removed the outer layers of the concretion. I would soak what you have left in water, and then freeze and thaw until it splits. There may be a fossil inside. 

[Mark Kmiecik]

On 6/26/2019 at 4:02 AM, Rob Russell said:

Yes, you’ve removed the outer layers of the concretion. I would soak what you have left in water, and then freeze and thaw until it splits. There may be a fossil inside. 

Yup -- very often the MC concretions are formed in concentric layers. Keep up the freeze/thaw. Most of the time concretions this size will contain a single pinnule from a Pecopteris or Neuropteris, or it may have another small fossil inside. This size is just right for a spider or such. Don't hammer it! Tap the edges lightly, but don't HAMMER it!