Buddy of mine found this in a creek, Eastern Kentucky. Anyone able to help him with an ID and general time frame? I’m more curious about the “host” rock than the fossil. The host is very heavy for its size.
The fossil is actually a cast ( an imprint ) of a turritella gastropod ( sea snail ). As smokey says, it may be shale. Eocene epoch, 35-55 million years old, as a guess.