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This one has been sitting in my "interesting but I have no clue" pile for a while. When I found it, I was splitting limestone laying in the stream. I've found that when you split limestone, immediately after splitting you'll get a couple moments of a sharp looking specimen before things start to oxidize. The limestone is a very dark gray, or almost black color. You either see black limestone or white calcite pieces while splitting. I split this particular piece open and right in the middle was a 3-4 cm long, 8 mm wide gold looking rectangle in the middle of the flat broken limestone. I thought I wouldn't get to recover it, but one hammer hit later it popped out and I was able to save it. I do find that plants in the limestone seem to get the gold or pyrite type preservation. I've found one small straight shelled cephalopod preserved like this. But overall, it's very rare here. I have maybe 3 or 4 larger pieces of what I'd called pyrite type material I've recovered. Below are some stacked microscope photos of it. The scale in the first photo is 1 mm for each mark. You can see the grain that runs left to right. This looks like wood to me, but I haven't had that confirmed before. The next two photos are a view looking from the bottom to the top of the first photo. What has me most curious are the perpendicular grain marks that are found in this area. They don't seem to just be on the outermost layer, as you can see more deeper. I'm not sure if this is some sort of perpendicular crystal pattern, or it's just the shape of the original material that was replaced with the mineral. And maximum zoom. A stack of 12 microscope images taken through the lens in the same area of the above photo. And that's it. Is this a small piece of woody material that was preserved in the sea? I wonder if vinegar would clean this up or destroy the mineral as well.

So most of what I find is Metacoceras or Pseudorthoceras, two very common cephalopods locally. I've found a few Solenochilus, but they are different enough that I know what I found right away. This specimen was discovered as a body chamber. I thought Metacoceras, because, why not? Anything of this shape usually is. After some moderate prep, I revealed some more body chamber, but not any suture marks. The venter is oddly shaped as well, with a shallow U shape. It might be crushed, so I didn't pay it too much mind. I also discovered that the body chamber is much larger than any Metacoceras specimen I have found to date. In viewing the paper A NAUTILOID CEPHALOPOD FAUNA FROM THE PENNSYLVANIAN WINTERSET LIMESTONE OF JACKSON COUNTY, MISSOURI (full paper), I found plate 5 which features Domatoceras. They are known to exist here, but I've never found anything definitive. Here is the plate from the article: Here is a Metacoceras (CG-0071) on the left, and the specimen in question (CG-0068) on the right. Here is the venter of CG-0068 showing the two ridges marked with arrows. I feel these are similar to the ridges shown in Figure 2 of Plate 5 And that is that. Any cephalopod people have an opinion? I could prep it more, it's just at the labor intensive micro prepping state right now with solid cement like limestone overlaying it. One more photo of it for some additional context: