[Mgretchen (OP)]

I found this conglomerate in the surf on a remote area of Avalon, NJ this past summer.  The rock appears to have a "+" symbol inside one of the stones pressed into the rock structure. I placed a pen in the pic for scale. This is very strange and I never seen anything like it.  Please advise if you have any ideas what it could be.

Thanks!

Mike

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[CliffordK]

Either God has a sense of humor...

or you have found a fragment of glass/pottery/ceramic.

It could be either American or European in origin (or elsewhere).  The print doesn't look ancient.. so I'm thinking it can't be more than a few hundred years old. 

Looking at that more.
If brown was the natural color of the glaze on the ceramic.
And the (X) was a stamp.
Then white is where the glaze has weathered/worn through which accentuates the stamp.
I am having troubles understanding the surface irregularity.

Perhaps that is wrong...  perhaps the color was white, and the brown came later.  Thus, the cracked surface is showing up brown along with the depressions around the (X).

[RD]

If not an artifact maybe a microfossil in cross*-section ...

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the X appears to have bulbous extremities: like a bathroom tap (faucet) ...

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or this ...

[ Invalid Attachment ] http://www.sciencephoto.com


[* pun not intended ]

[JimBob]

If the with rock is limestone then I suspect the cross is the result of a foramanifera - or a fusalinind if older than Triassic. (The later is likely since you found it on a NJ shore.)

What puzzles me is what is all of this set in, i.e., what is the black stuff? It looks like oil tar.

Then again, it could be a sport of nature set there to test our faith.    []
 

Can you give us a detailed description? Will either of the parts scratch with a sharp knife? Is the black stuff finely granulated and the compressed coal? (Will it leave a black mark?)

[RD]

On closer inspection it looks like it's bigger than it first appears ...

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[JimBob]

And how big is that?

[RD]

And how big is that?

From the pen tip included for scale I'd estimate the full size (green line) is about 3mm across.

[Bored chemist]

I wondered if it was something like this
http://www.minerals.net/glossary/terms/a/asterism.htm
 but a fossil looks more likely.

[CliffordK]

I like the photo of the Radiolarian, although I think they may be a bit too small for what is observed.

I'm still leaning towards a mark on a ceramic. 

Can you tell if it has any 3-D texture?  Feeling with a finger, or doing a light paper&pencil rubbing?

[RD]

Some diatoms have cruciform symmetry ...


http://en.wikipedia.org/wiki/Diatom

[Foolosophy]

I found this conglomerate in the surf on a remote area of Avalon, NJ this past summer.  The rock appears to have a "+" symbol inside one of the stones pressed into the rock structure. I placed a pen in the pic for scale. This is very strange and I never seen anything like it.  Please advise if you have any ideas what it could be.

Thanks!

Mike

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How old do you think it is? Any clues?