In some localities, such as Scandinavia and Morocco, the fossils of orthoconic nautiloids accumulated in such large numbers that they form limestones composed of nonspecific assemblages know as cephalopod beds, cephalopod limestones, nautiloid limestones, or Orthoceras limestones in the geological literature.
described Geisonocerina among a suite of 12 nautiloid genera from the Ordovician of the Black Hills, South Dacota.
Intejocerida is the name given to a group of generally straight shelled nautiloid cephalopods originally found in Lower and Middle Ordovician sediments in the Angara River basin in Russia; defined in the Treatise as an order, and combined there with the Endocerida in the Endoceratoidea.
Paraplectronoceras is a very early nautiloid from the middle Late Cambrian, named by Chen and Qi, 1979, type species Paraplectronoceras pyriforme, for small, endogastrically curved forms found in the upper Yenchou and Wanwankou members of the Fengshan Formation of northeastern China.