Here are some Bellerophon fossils I found in the Kope Formation in Carroll County, Kentucky. Until now, I have not found growth line patterns found on the shell. Usually, I just find a smooth shell pattern with the ridge line running the length of the shell. A Cyclonema fossil is attached to the Bellerophon.
It is a neat find and I hope to clean with air abrasion sometime to reveal the growth lines.
This Bellerophon mold is typical of the ones I find at Ordovician Period road cuts around the Louisville area. It has a nice whirl at one end of the fossil.