Your ammonite probably is...

Hildoceras

Hildoceras had a narrow, slightly evolute shell. It had three ventral keels separated by a pair ventral grooves. Another groove ran along the middle of the shell. Well-spaced, coarse, curved radial ribs were present between the side groove and ventral keel. Its whorls had rectangular cross-sections.

Public Domain, https://commons.wikimedia.org/wiki/File:Hildoceras_spp.jpg