What could this even be? Weird form w/shells

[nikkisixx]

I can't even wrap my mind around what I'm looking at. I've never seen anything like it. It looks like it has shells stuck in it. More pics to come. Found in Parker Arizona behind my father in law's house.

[nikkisixx]

This gray spot has a pattern of diagonal lines in a circle around the edges.

[nikkisixx]

There's a brown shell looking thing on the outside and there are other markings on the rock that look like similar impressions.

[nikkisixx]

Another area that looks like shells, note the two white fragments with lines. From this angle it doesn't look like they go together-but I assure you the pattern is continuous.

[DPS Ammonite]

I wonder if this is a piece of limestone breccia. Does a knife/ piece of steel scratch the light colored receding matrix? Does a knife scratch the brownish pieces that stick out?

[nikkisixx]

It does not scratch.

[nikkisixx]

I tried it on the lighter colored receding matrix and on the shell looking part-no mark on the outer receding rock but it made the shell shiny on the scratched parts.

[ynot]

I think it is another piece of weathered limestone. The area that looks rusty is oxidized iron, and the white (and impressions) are shell fossils.

Tony

[nikkisixx]

I agree. I looked further into limestone *breccia and it looks like that's what it is! 

[tmaier]

Yeah, weird. It looks like one nodule of fossiliferous limestone (the grey) that became encased inside more fossiliferous limestone (the beige), and then the outer layer of limestone is now erroding away.