Wikipedia
Uranoceras
Uranoceras is a barrandeocerid genus from the Middle Silurian belonging to the family Uranoceratidae, characterized by its loosely coiled, gyroconic shell of 1.5 to 2 subquadrate whorls.
The shell of Uranoceras is typically smooth but may have growth lines that form a hyponomic sinus on the venter. The Siphuncle is large, displaced slightly ventral from the center. Septal necks are straight; connecting rings cylindrical, thin, and strongly contracted where they meet the necks.
Uranoceras has been found in Indiana, Illinois, and Wisconsin in the United States; Anticosti Island in Canada; and in both central and northern Europe.