Dawsonoceras Hyatt, 1884

Emended diagnosis. Slender, circular or slightly compressed orthocones with symmetrically curved septa and straight transverse sutures. Sutures parallel to the annulationsin each groove of the annulations. Annulations regularly spaced, with fine transverse ornament, or growth lines. Growth lines in some species festooned. In some specie slongitudinal ridges that may form nodes at the ridges of the annulations. Siphuncle subcentral in early growth stages, central in late growth stages, narrow, but expanded within the chambers. Septal necks short suborthochoanitic to achoanitic, in advanced forms short reticulate. Incipient annulosiphuncular deposits, and mural cameral deposits are known.