Part II, Cephalopods of the Ordovician Cat Head Member, Lake Winnipeg, Manitoba

Corals and a cephalopod from the Whirlpool Formation (latest Ordovician, Hirnantian), Hamilton, Ontario: biostratigraphic and biogeographic significance

“…2a-c), the shell is "very slowly enlarging" to a diameter of only 9 mm, with five transverse annulations in 9 mm and with fine longitudinal striae that are more conspicuous than the fine transverse ones. Flower (1946) noted that generic reassignments are necessary for annulated Ordovician species placed by earlier workers in the Devonian genus Spyroceras Hyatt, 1884. Likely possibilities are Gorbyoceras and Anaspyroceras Shimizu and Obata, 1935, in which he placed some of those species.…”

“…Although the Whirlpool specimen lacks the more highly oblique annulations illustrated from various Gorbyoceras species in the Richmondian of the Cincinnati Arch region (Flower, 1946;Frey, 1995), it is assigned to that genus because there is curvature of the shell axis, while the septa within the annulations appear more concave and closely spaced than those of the sectioned Anaspyroceras specimen of Richmondian age from Manitoulin Island, illustrated by Copper (1978, pl. 5, fig.…”

Late Ordovician conulariids from Manitoba, Canada

“…Fossils, generally rare but abundant at some levels, include megascopic non-calcareous algae, palynomorphs, trilobites (notably Isotelus sp. ), obolid, lingulid, and strophomenid brachiopods, nautiloid cephalopods, possible hydrozoans, dendroid graptolites, and sponges, in addition to the conulariids (Whiteaves, 1897;McGregor and Cramer, 1971;Flower, 1971;Rigby, 1971;Fry, 1983;Westrop and Ludvigsen, 1983). Several of these groups are remarkably well preserved; the soft algae (''seaweeds'') are among the best known anywhere in the early Paleozoic.…”

Redescription of the Ordovician Cephalopod Genus Centroonoceras Kobayashi, 1934

“…Occurrence.-In North China, Llanvirn (upper Middle Ordo vician) of the Gangwon-Do area in South Korea (Kobayashi, 1927(Kobayashi, , 1934 and the Ords area in China (Chen and Zou, 1984). In Laurentia, Chazy (upper Middle Ordovician) of the Champlain Valley (Flower, 1946(Flower, , 1955 and Black River to Rockland (lower Upper Ordovician) of Kentucky (Foerste, 1912;Frey, 1995) in the United States of America, and Black River of Ontario (Foer ste, 1932(Foer ste, , 1933Wilson, 1961) and Newfoundland (Stait, 1988) in Canada.…”

“…The type species, Centroonoceras to kunagai, was originally described by Kobayashi (1927) as a new taxon belonging to the family "Ooceratidae" of the order Oncocerida. When Kobayashi (1934) proposed Centroonoceras, he diagnosed the genus as an orthocerid cephalopod whose closest relationship was with Sactorthoceras Kobayashi, 1934. Flower (1946 later placed Centroonoceras in the family Sactorthoceratidae, an assignment followed by most subsequent workers, in cluding Balashov and Zhuravleva (1962), Sweet (1964), and Chen and Zou (1984).…”