Genus Zygospira Hall, 1862

Type species: Producta modesta Say, 1847 .

Stratigraphic distribution: Caradocian to Ashgillian (Ordovician). Geographic distribution: cosmopolitan.

MIN

Zygospira modesta (Say, 1847) Locality: Waynesville, Ohio, USA Stratigraphy:?Ashgillian, Late Ordovician MIN

Zygospira cincinnatiensis (Meek, 1873) Locality: Waynesville, Ohio, USA Stratigraphy: Lower Silurian