Truly, a beautiful fossil and reveals itself out the rock matrix so well. It makes me think of stone flower bud.
These fossils came from Sulphur, Indiana, USA I-64 road exit which is to the west of Louisville, Kentucky. It was collected at the same time as yesterday's Archimedes.
These blastoids are either Pentremites sodoni or Pentremites wellen. They are from the Mississippian period (known outside the United States as Carboniferous) which about 290-350 million years ago. The rock section is Chesterian and the formation these came from was the Haney.