Conodonts: Microfossils of Distinction (PA-06)
First described in 1856, they are still a mystery. Fossil impressions of strange animals found recently in Montana contained groups of conodonts. They appeared to be embedded in the digestive organs of a small, primitive marine animal. Five or six kinds of conodonts were present in one individual.
Our Hoosier State Beneath Us: Paleontology