Much better fossils were located in China:
Noeggerathiales were important peat-forming plants that lived around 325 to 251 million years ago. Understanding their relationships to other plant groups has been limited by poorly preserved examples until now.
The fossils found in China have allowed experts to work out that Noeggerathiales are more closely related to seed plants than to other fern groups.
No longer considered an evolutionary dead-end, they are now recognized as advanced tree-ferns that evolved complex cone-like structures from modified leaves. Despite their sophistication, Noeggerathiales fell victim to the profound environmental and climate changes of 251 million years ago that destroyed swamp ecosystems globally.
University of Birmingham, “‘Pompeii of prehistoric plants’ unlocks evolutionary secret” at ScienceDaily
Curiously, we keep finding that ancient life forms were more complex or advanced than thought, not that they were simpler and more primitive than thought. What does that imply about the drivers of our expectations?
The plants were preserved in a bed of volcanic ash, hence the reference to Pompeii, a city that met the same fate in 79 AD.
The paper is open access.