Hello. I found this stone in Austin Texas, USA. It is covered on both sides with these little possible leaves, most at about 2-3 centimeters in length. Few are very clear, so I tried to get a couple good photos of the best ones. It was sitting at the top of a rocky hill in northern Austin, I believe what is called the Great Hills area. There were a lot of bivalves nearby, even snagged a lovely Exogyra ponderosa. But this one seems to allude me. Leaf shaped fronds, but the inside shape almost seems more animal than plant.
Any help is deeply appreciated!