Numerous specimens of Tabulaconus Handfield, 1969, have been collected in carbonate buildups within the Adams Argillite (Early Cambrian, Tatonduk area, Alaska). The wall structure of this form has been investigated, along with contemporaneous archaeocyaths and algae, through the use of polished ultra-thin sections (2–3 μm thick) and scanning electron microscopy. The results of this microstructural comparison indicate that despite diagenetic alteration Tabulaconus has a skeleton that is unlike any presently known and is quite distinct from associated algae or archaeocyaths. It is more elaborate than that found in the archaeocyaths but has not reached the stage of complexity seen in the primitive coral Cothonion Jell and Jell, 1976. The presence of some elongated units may represent an initial step towards the fibrous skeleton typical of Paleozoic corals.

This study shows that even though diagenesis alters the original microstructure of calcareous skeletons, the resultant fabrics and detailed structures can be useful in systematic descriptions.

Tabulaconus is removed from the Gastroconidae Kordae due to the presence of rudimentary septa and constitution of the tabularium. A number of species assigned to the genus Bačatocyathus Vologdin and included within the Archaeocyatha appear to be examples of Tabulaconus or very close relatives. An emended description of Tabulaconus kordae, the type species, is proposed.

The wall of Michelinia meekana Girty is composed predominantly of lamellae that are approximately parallel to the median dark line, confirming its placement in the genus Michelinia s.s. The presence of a Praemichelinia-type microstructure in some parts of the wall is a recurrence of primitive architecture that suggests derivation of Michelinia from Praemichelinia.

The Oñate Formation of Middle Devonian (Givetian) age is exposed in the Mud Springs Mountains of New Mexico, where it is represented by an unusually shaly and extremely fossiliferous facies. Tabulophyllum traversensis (Winchell) found here is the only rugose coral species known thus far from Middle Devonian rocks of New Mexico and is of special interest as evidence of migration between the area of the Oñate occurrence and those in the Cedar Valley Limestone in Iowa and the Traverse Group of Michigan. The occurrence is also of interest because of the association of the Oñate coral with the receptaculitid Sphaerospongia sp. cf. S. tessellata (also known from Canada, Australia, and New York). The corals apparently utilized receptaculitids as a solid substrate for post-larval growth and developed an extremely broad flat base, fixed to the upper surface of Sphaerospongia.

Intraspecific morphological variations have been investigated based on 1,090 specimens of a Pleistocene solitary scleractinian coral, Caryophyllia (Premocyathus) compressa Yabe and Eguchi. Special attention has been paid to variations in septal arrangements, septal numbers, insertion patterns of third-cycle septa, and pali. The specimens contain nine different septal plans from hexameral to decatetrameral, among which those having a decameral plan are the most common. There is a clear regularity in number and position of the third-cycle septa. Specimens in which the third cycle is incomplete are also considered to be mature forms. Number and position of pali are intimately related to the number and insertion pattern of the third-cycle septa. In extreme cases, there exist specimens having only two cycles of septa and lacking pali. Ninety-nine varieties in septal arrangements are considered to be present in the fossil population, although only 57 have been found in the collection. The present species includes many specimens which do not show bilateral symmetry.

The Wamp Spring section of the Bird Spring Group consists of approximately 1,600 feet of carbonate rocks subdivided into a basal platy limestone member, lower cliff-forming member, and upper cliff-forming member. Triticites, Schwagerina, and Schubertella kingi in the platy limestone member indicate an early Wolfcampian age. Schwagerina, Schubertella kingi, and a distinctive assemblage of brachiopods, similar to the West Texas fauna, including Kozlowskia kingi, Elliottella aff. E. multicostata, Leurosina sinesulca, Gypospirifer cf. G. infraplicus, and Composita cf. C. apheles, indicate that the upper cliff-forming member is late Wolfcampian. The lower cliff-forming member is tentatively assigned to the middle Wolfcampian. The Wamp Spring sequence correlates temporally with the BSe “formation” of the Bird Spring Group.

In addition to the previously mentioned taxa, the fossil-rich upper cliff-forming limestone member includes the new species Pontisia boodi, Crurithyris wampensis, and Calliprotonia(?) n. sp. A, as well as Hustedia culcitula, Crenispirifer(?) sp., Cenorhynchia(?) sp., Kutorginella(?) sp., marginiferids, lyssacine hexactinellid sponges, pleurotomarid and bellerophontid gastropods, cidaroid echinoids, rugose corals, cylindrical cryptostome bryozoans, and nuculids.

Open-coiled euomphalacean gastropods have been identified for the first time in the Upper Cambrian Eminence Dolomite of Missouri. These gastropods have a triangular whorl profile and are conspecific with Hyolithes walcotti described from the Upper Cambrian of Nevada. That species is questionably reassigned to the gastropod genus Macluritella, hitherto known only from the Lower Ordovician of Colorado.

Two life positions of fossil naticid opercula are recognized in Pliocene deposits of Hokkaido, northern Japan. In one position, the operculum seals the aperture. In the other position, the operculum is pressed against the shell base adjacent to the aperture. The death position of the head-foot mass can be reconstructed from the two opercular positions, which coincide, respectively, to naticids that died with the head-foot mass retracted into the shell, and those that died with it entirely extended from the shell.

Spirodentalium Walcott, 1890, was originally described as a scaphopod. A reinterpretation of the type lot suggests that its overall shape is that of an open-coiled gastropod. If so, this is probably the earliest known open-coiled form and it is sinistral in coiling direction.

Seven previously described and seven new taxa of gyrodiform naticoids from West Coast Late Cretaceous–Paleocene age strata are discussed. Gyrodes (Gyrodes) dowelli White of Turonian age is a typical Gyrodes; G. robustus Waring from the Paleocene has the shape of Gyrodes s.s. but lacks the crenulations. G. greeni Murphy and Rodda, G. yolensis n. sp., G. quercus n. sp., G. banites n. sp., G. canadensis Whiteaves, G. pacificus n. sp., and G. expansus Gabb comprise the new subgenus Sohlella, which thus ranges from Cenomanian through Maastrichtian. Gyrodes robsauli n. sp. resembles “Polinices” (Hypterita) helicoides (Gray), and Hypterita is reassigned to the Gyrodinae as a subgenus of Gyrodes. Gyrodes onensis n. sp. of Albian age is similar to the G. americanus group of Sohl (1960). Three texa—Natica allisoni (Murphy and Rodda) of Cenomanian age and N. conradiana Gabb and N. conradiana vacculae n. subsp. of Turonian age—which have all been previously considered to be Gyrodes are placed in Natica. Well marked relict color patterns on N. conradiana and N. conradiana vacculae suggest that these naticids from northern California and southern British Columbia were tropical forms.

Diversity of taxa and size of specimens are reduced at the end of the Turonian, suggesting a change in West Coast marine conditions at that time.

Brachylepas americana n. sp. is described from abundant and well-preserved capitular and basal whorl plates from a littoral facies in the basal part of an Upper Cretaceous (upper Campanian) conglomerate questionably assigned to the Brownstown Formation in Hot Spring County, Arkansas. The new species resembles the European littoral Campanian–Maastrichtian species B. guascoi (Bosquet), and differs markedly from the only other known American species, B. angulosa Collins, from the Upper Cretaceous middle Ripley Formation of Mississippi. A few juvenile carinae of Virgiscalpellum may represent V. gabbi apertus Collins, previously known from the Ripley and basal Prairie Bluff Formations in Mississippi.

Jujuyaspis borealis is reported from earliest Ordovician (North American usage) limestones in central Texas and western Utah, the first time this species has been recognized in the United States. Jujuyaspis is a widespread olenid trilobite that occurs near the base of the Tremadoc Series in a variety of lithologies in North and South America, Europe, and Asia. When international agreement is reached on the exact horizon at or near the base of the Tremadoc Series that is to be used as the Cambrian–Ordovician boundary, Jujuyaspis will likely prove to be a very useful taxon for recognition of the boundary interval.

New flexible crinoids referable to Taxocrinus Phillips and Onychocrinus Lyon and Casseday are made known from Carboniferous (Mississippian, Chesterian) strata of Tennessee. Taxocrinus strimplei n. sp. and Onychocrinus sp. A are reported from a single locality in the Bangor Limestone in Cumberland County, east-central Tennessee. Specimens of both species are characterized by having fewer numbers of brachials than any species yet referred to either genus. Both the evolutionary development of their brachial series and their stratigraphic position suggest that these species are at or near the end of lineages of these two genera.

Piscichnus brownii n. gen. and sp. is described from the Plio-Pleistocene Koobi Fora Formation of northern Kenya. The trace fossil is an unornamented, shallow, dish-shaped structure preserved in concave epirelief on sandstones. This structure is interpreted to result from the nest-excavating activities of fish.

Perryella olsoni, a new temnospondylous amphibian from the lower Permian Wellington Formation of northern Oklahoma, is described. Features of the palatine, quadratojugal, and stapes are distinctive among described temnospondyls. The specimens share derived character states with the Dissorophoidea and Trimerorhachoidea, but cannot be assigned to either of these superfamilies as presently defined. The difficulties of temnospondyl classification in light of the confusion of primitive, juvenile, and paedomorphic features are discussed.

Fragments of a ceratopsian dinosaur from the Maastrichtian Hell Creek Formation, Garfield County, Montana, are unlike any known ceratopsian. Diagnostic features include a low, rounded nasal boss, an especially deep rostral-premaxillary pit, and paired choanae. The snout is elongate. The new taxon, Ugrosaurus olsoni, is referred to the Ceratopsidae.

The axial column in Labidosaurus is thoroughly described. Two different vertebral “morphs” are found to occur in this genus. One type is that which is classically illustrated for Labidosaurus, while the other shows alternation in height and construction of the neural arches and neural spines. A brief description of the modifications of muscle attachments in alternating forms is outlined. Analysis shows that such a structural modification probably allowed (more) efficient dorsiflexion and lateral flexion of the vertebral column. The occurrence of alternation of neural spine and arch structure is probably a primitive characteristic, but becomes variously modified in different forms. The variability observed in the axial column suggests that Labidosaurus may have been sexually dimorphic, or that the genus may consist of two different species.

A sinkhole locality in the Wasatch Plateau has yielded Utah's first record of the American mastodon. At nearly 3,000 m this fossil-bearing site denotes the highest elevation yet reported for Mammut americanum, and demonstrates that mountainous terrain was not a barrier to dispersals. A presumably preferred habitat of spruce-fir open forests, similar to that in the area today, was present during the time of the mastodons reported here. Two incomplete individuals of M. americanum are the only fossils that were found in the sinkhole. Entrapment appears to have been the cause of death. Since the record of M. americanum in western North America is sparse, the present find has added significance in providing more information about the nature of this animal. A possible association of a recovered spear point fragment near the fossils indicates the possibility that man and mastodon were contemporaneous here. Three independent datings were run on mastodon bone. Two based on carbon-14 yielded dates of 7,090 ± 200 yr B.P. and 7,590 ± 100 yr B.P., while the third, using the racemization process, indicated an age of less than 10,000 yr B.P.