plate or shell

[anonaddict]

location: aarhus, denmark

found: loose beach rock

units: metric

own ID: looks like armor of some sort, it bears a resemblence to orthocone nautiloids that are common in this type of stone (ølandskalk in danish but idk english name and danish names in science are really bad to translate), but doesnt have the internal structure you'd expect and the size would be several times greater than anything ive seen before leading to the assumption it must be plate armor or shell of some type

 

[Kane]

Seeing trace fossils here, no shell.

[Rockwood]

Shallow water currents can create shapes like this, or it could be concretion. 

[anonaddict]

9 minutes ago, Kane said:

Seeing trace fossils here, no shell.

the whole rock is very clearly rounded exactly like it would be if it was a massive natiloid. the rounded surface *is* covered with trace fossils but the surface below has a uniform surface

 

below ive marked the parts that are are a thin layer of matrix 

[Kane]

Concretions are also rounded. Not seeing nautiloid, sorry.

[anonaddict]

the surface has the same texture as this rock has in the marked area

[anonaddict]

5 minutes ago, Kane said:

Concretions are also rounded.

thats true but i've never seen a concretion that looks like the fragment of a cylinder. If it actually is a concretion can you elaborate on how something like this would form with such a clearly defined surface similar to the texture left where fossils been removed like in my previous post?

[Fossildude19]

3 minutes ago, anonaddict said:

thats true but i've never seen a concretion that looks like the fragment of a cylinder. If it actually is a concretion can you elaborate on how something like this would form with such a clearly defined surface similar to the texture left where fossils been removed like in my previous post?

 

I've seen tons of concretions that are cylindrical in shape. 

Concretions form around biologic masses, that sometimes are preserved, but often not preserved.

Concretions can form in all sorts of oblong, cylindrical, ovoid, circular shapes.

[Rockwood]

A distinct layer often referred to as rind is common on concretion. 

[anonaddict]

So how would I go about distinguishing between this space where my clear assumption is that an orthoceratite has been

 

and the rock in question

 

which has a similar pattern on the exposed part of the surface. and a hypothetical fossil with leftover matrix? At least to me it does not seem clear how to tell these 3 things apart

[Rockwood]

Form and texture. Compare them to known fossils. 

[Fossildude19]

I am not seeing anything I would call a fossil, but you could keep it aside, with a question mark for ID.

Personally, I don't think it is any kind of fossil.

Does not look like any kind of orthocone or armor that I am aware of.

 

[anonaddict]

1 hour ago, Rockwood said:

Form and texture. Compare them to known fossils. 

looks similar to the central part of the back shield of some trilobites, but vast majority of my knowledge is on cephalopods and sea urchins since those are the most common fossils on danish beaches

[anonaddict]

52 minutes ago, Fossildude19 said:

I am not seeing anything I would call a fossil, but you could keep it aside, with a question mark for ID.

Personally, I don't think it is any kind of fossil.

Does not look like any kind of orthocone or armor that I am aware of.

 

I always do for things i'm uncertain of, and then plan a trip to a local paleontology department for more information

[Rockwood]

28 minutes ago, anonaddict said:

looks similar to the central part of the back shield of some trilobites, but vast majority of my knowledge is on cephalopods and sea urchins since those are the most common fossils on danish beaches

Sorry, but the texture doesn't show well enough in the photos for me to say more.