Memoir 28

Part I: New American Wutinoceratidae with review of Actinoceroid occurrences in eastern hemisphere

Part II: Some Whiterock and Chazy Endoceroids

By R. H. Flower, 1976, 76 pp., 3 figs., 16 plates, 1 index.

Descriptions of some new Wutinoceratidae from North America. New species of the Wutinoceratidae are described from upper Whiterock beds of Nevada, Oklahoma, and Newfoundland. In North America the family is found only in late Whiterock beds. Occurrences in Asia, particularly eastern Asia are discussed. Some new reports seemingly conflict with the proposed sequence of (1) Polydesmia, (2) the Wutinoceratidae, and (3) more advanced actinoceroids including the Ormoceratidae, Armenoceratidae, and Actinoceratidae. Some suggestions are made to the vexing problem of intercontinental correlation of Ordovician beds and cephalopod faunas.

In a previous work the writer summarized the Wutinoceratidae then known, described some new forms, suggested that the Whiterock Stage is marked by the development of this family, and that it is in this interval that the Wutinoceratidae, the only Actinoceratida then developed, became nearly worldwide in distribution. Involved with this concept was the recognition of Whiterock equivalents in the Baltic region, in eastern Asia, and in Tasmania. No such occurrences are yet known in South America, but the Ordovician faunas known there are restricted. The present work combines descriptions of some new Wutinoceratidae from North America, with some remarks on probable correlations of the strata from which they came, and an attempt to summarize some recent work elsewhere, mainly in eastern Asia.

Occurrences of the Wutinoceratidae in North America may be summarized as follows: Nevada-Wutinoceratidae are not uncommon in the Antelope Valley Limestone, but are known exclusively from the Palliseria-Maclurites-Girvanella zone, which seems from later observations to be a significant temporal unit rather than a magnafacies representing different parts of the Antelope Valley Limestone at different regions. The species now known are as follows: (1) from Ikes Canyon and the Toquima Range: Wutinoceras lobiferum, W. planiseptatum, W. margaretae, W. huygenae, W. lowelli, Cyrtonybyoceras adamsi, Adamsoceras isabelae, A. gracile, A. attenuatum, A. toquimense; (2) from the Hot Creek Range, Wutinoceras reubeni; and (3) from Meikeljohn Peak, Adamsoceras leonardi.

Western Utah has yielded only two described forms, Adamsoceras lehmanense from the Lehman Limestone and Wutinoceras davisi from black shales, low zone N, high in the Kanosh shales, or a black limestone in the Lehman Limestone. Only fragments have been found subsequently; one consists of only two camerae of a fairly large form, apparently a Wutinoceras from the Lehman Limestone. Oklahoma had formerly yielded one Whiterock actinoceroid; two more are added. All are from the Oil Creek Limestone. The Table Head Limestone of Newfoundland has also yielded some species.

Interestingly, the actinoceroids in Utah and Nevada are confined to the upper part of the Whiterock Stage. In Nevada they are found in the Palliseria zone, in Utah in zone N, high Kanosh and Lehman Formations. In Oklahoma the known specimens are from the Oil Creek Limestone and not from the underlying Joins Formation. In Newfoundland the actinoceroids appear in the earliest cephalopod associations in the Table Head Limestone, only a few feet above its base, extend through the lower thick division L, of light-gray-weathering massive limestones , and continue on into the thinner bedded black limestones low in division M, and more sparingly into upper M, where trilobite-rich limestones alternate with black shale. Division N, consisting of black shales and siltstones, has yielded only graptolites and inarticulate brachiopods among its megafossils. It may be that the actinoceroids appear earlier in Newfoundland than in the Great Basin or in Oklahoma, but it may also be that the Table Head deposition began later than did the Whiterock in the Great Basin or in Oklahoma.