Fingerprint-like fossil and suspected mass extinction event imprinted rock

[CornelDumitru]

Hello!

Please help me with this two part question. 

First, to ID the fossil.

The following 3 specimens are imprinted on the same ("the upper") side of this rock.

Specimen #1:

 

 

 

 

 

 

 

Specimen #2:

 

 

Specimen #3:

 

 

[CornelDumitru]

Second, please help me place this rock in a geological context.

The "top" (or upper) side contains the fossil prints from the post above.

 

 

 

 

"Bottom" side:

 

This is the "Top" side (it has the fossil prints):

 

I picked up this rock in Romania, Braila county, close to the Danube river. It was just embedded in dirt.

The material is hard, like silica. It does not react to vinegar.

It takes a good polish:

 

 

Edited October 20, 2021 by CornelDumitru

[Plax]

silicified stromatoporoid?

[CornelDumitru]

The "bottom" layers, the yellow-reddish ones, and only this ~1 cm thick "slice", show many flakes of more-or-less oxidized metal, or pyrite, or something. 

Like these:

 

 

 

edit: this is a beauty; the flakes' stream follows the disturbance: 

 

 

Edited October 20, 2021 by CornelDumitru

[CornelDumitru]

46 minutes ago, Plax said:

silicified stromatoporoid?

This would annihilate my (unsupported) supposition, which is K-Pg boundary, push the rock a few 100Ky back and maybe turn it upside-down also.

Thanks!

 

[Plax]

The rock is very crystalline but have seen fossils replaced like this. If the rock is from the K/PG boundary in age it is probably not a stromatoporoid unless it was reworked as a transported cobble. Is there any chance this could be something modern showing on the surface of an igneous or metamorphic rock?

[CornelDumitru]

 

2 hours ago, Plax said:

 Is there any chance this could be something modern showing on the surface of an igneous or metamorphic rock?

 

"Top" side for relief, context:

 

 

 

Specimen #1 for context:

 

 

 

 

Specimen #3 for context:

 

 

 

 

To me the fossil specimens look well integrated in the context, as crystalline as the surrounding material.

K-Pg boundary is just a suspicion of mine, an amateur. 

 

[CornelDumitru]

With all due respect I will ask for one more shot at an ID.

Could these specimens be remnants of shield plates from armoured jawless vertebrates, Pteraspidomorphi?

The following photos are all of the one and only specimen #1.

 

 

 

 

 

 

[jpc]

These fingerprinty things look a lot like fish scales to me.  I see a lot of these in the micro fossil collections form the late Cretaceous Lance Formation. 

[CornelDumitru]

I am grateful for the help received here!

There is one more area of interest and I would not start a new topic, so please work your magic again:

Is this a turtle shell fossil?

It sits on the "bottom" side of the rock.

The first photo is the most recent; some abrasion intervened.

 

 

 

 

 

[Lone Hunter]

Not seeing turtle shell, maybe something like bryzoan? What are the circled areas?

[CornelDumitru]

1 hour ago, Lone Hunter said:

What are the circled areas?

They are areas with hypothetical "flakes of more-or-less oxidized metal" as shown in my 3rd post in this topic.