Protocycloceras ordinatum (FOSSIL) (Billings, 1865 †) Canada, Quebec, Vaudreuil-Soulanges
Protocycloceras philipsburgense (FOSSIL) Ulrich & al., 1944 † USA, Vermont, Franklin
Protocycloceras rushense (FOSSIL) (McChesney, 1859 †) USA, Ohio, Guernsey
Protocycloceras smithvillense (FOSSIL) Ulrich & al., 1944 † Arkansas, Lawrence County
Protocycloceras xerxes (FOSSIL) (Billings, 1865 †) USA, New York, Orange