Memoir 21

By R. H. Flower, 1968, 36 pp., 5 plates, 1 index.

Botryceras enigma is an apparent endoceroid cephalopod known from a remarkable endosiphuncle in which sheaths are sparingly developed or preserved and the simple cones terminate in a group of centrate tubes, rather irregular, but divided anteriorly into two groups. No forms or class affinities are known, but the structure indicates tentative assignment to the order Endoceratida.

A large endoceroid, Cameroceras alternatum, is described from strata of Black River age from the province of Quebec. The specimen here described was collected by Dr. T. H. Clark who submitted it to the author for study. It is from beds of Black River age at St. Raymond, Quebec. It is further contribution to our knowledge of endoceroids in the Ordovician, a matter on which available material is scant, owing to the large size of specimens and the difficulty of extracting them from the containing beds, commonly hard and massive limestones. It may be noted that Black River beds of northwestern New York contain largely true Vaginoceras, which is found also at Ottawa and at the Paquette Rapids of the Ottawa River. It is known north to Cape Calhoun and occurs (Troedsson, 1926) in beds them attributed to the base of the Cape Calhoun Formation but may better be placed with the underlying Gonioceras Bay Formation. Oddly, the dominant endoceroids of the Platteville Limestones are forms with simple tubes, subcircular in section, terminating variously but without the compression of the cones apically or their termination in a vertical tube supported by two vertical blades.

Beds regarded as of Late Canadian age in Alaska have yielded endoceroids comprising four species, four new genera, three of which constitute the new family Yorkoceratidae, Yorkoceras, Sewardoceras, and Telleroceras. A fourth genus, Kugeloceras, is tentatively placed in the Proterocameroceratidae. The endoceroids here described were collected by Dr. C. L. Sainsbury, in connection with an investigation of the Teller quadrangle, York district, Seward Peninsula, Alaska. The region shows evidence of (1) Lower Canadian Ellesmeroceratidae, not included in the present study, and (2) a group of very unusual endoceroids, which seem Middle Canadian, or more probably from their specializations, Upper Canadian, in aspect. These beds, on which finer stratigraphic divisions do not seem possible, may represent a single general fauna. The endoceroids are remarkable, consisting of (1) Kugeloceras, a short endosiphuncle with a very blunt apex, represented by several specimens, all very short, and (2) a series of remarkable endoceroid siphuncles with somewhat expanded segments, segments nearly transverse and thus apparently well removed from the venter. These vary, but three species and three genera are recognized, while one unnamed specimen is distinct from all the others.

A small association in the Seward Peninsula of Alaska has yielded one new species of Franklinoceras and two new species of Proteoceras. The association is indicative of equivalence with the Crown Point and Valcour Limestones of the Chazyan of the Champlain Valley. A small collection from the Seward Peninsula of Alaska has yielded orthoconic cephalopods, including one new species of Franklinoceras and two of Proteoceras. Franklinoceras Flower has been known formerly only from F. elongatum, from the Crown Point Limestone of the Champlain Valley. Though the author had regarded the genus Franklinoceras as a compressed modification of the more abundant Ruedemonnoceras, it now seems likely that the compressed rather than the broad section, by which Franklinoceras is set apart from Ruedemannoceras, may be a primitive feature, hearkening back ancestral Plectronoceratina. As yet, it is still separated from an ancestral types by a considerable stratigraphic gap comprising the entire Middle and Upper Canadian, as well as the Whiterock Stage. Nevertheless, it is worth noting that any further finds of Franklinoceras outside of the range of the one previously known specimen would probably be in older than in younger beds. The broad section of Ruedemannoceras is found also in Madiganella of the Ruedemannoceratidae and is continued into the Mohawkian genus Ulrichoceras of the Cytogomphoceratidae.