The Cedar City Formation is divisible into three stromatoporoid biozones. These zones are differentiated by the mutually exclusive stratigraphic occurrences of the species 1) Syringostroma astrorhizoides, 2) Stromatoporella congregabilis and 3) Stachyodes crebrum. Chronologically, the zones range from late Emsian to early Frasnian. Lithofacies of the Cedar City are not restrictive as to the stromatoporoid species they contain.

A disc-like soft-bodied fossil recovered from the Farmers Member of the Borden Formation in northeastern Kentucky is described and is interpreted as a chondrophorine float, an internal feature. This is apparently the first report of a post-Devonian fossil porpitid.

Repaired shell breakage in Late Ordovician brachiopods from the Cincinnatian Series in the tri-state area of Indiana-Kentucky-Ohio may be described in increasing order of severity as scalloped, divoted, cleft and embayed. Concavo-convex brachiopod taxa display disproportionately higher frequencies of shell repair assigned to each category, whereas inflated, biconvex, plicate, sulcate taxa display disproportionately lower frequencies of shell repair. Certain plicate biconvex taxa lack examples of cleft and embayed valves. Plano-convex and dorsi-biconvex, costate taxa showed intermediate frequencies of shell repair, but lack representatives of embayed valves. Selective pressure for evolution of morphologic characters resistant to shell breakage may have favored phyletic trends of increasing size, geniculation and progressive development of a commissural ridge around the lophophore platform of the interior of the concave brachial valve of Leptaena and Rafinesquina. Size-frequency distributions for repaired and undamaged valves provide equivocal evidence of a size refuge from predator-induced shell breakage in Rafinesquina. Among the contemporaneous, potentially durophagous predators, nautiloids probably inflicted the sublethal injuries sustained by the brachiopods. The incriminating evidence includes a fragment of a crushing element imbedded in a valve of Rafinesquina that bears a very striking resemblance to calcified rhyncholites of Mesozoic to Recent nautiloids.

In southwestern Baja California Norte a new species of Early Tertiary Tethyan gastropod, Velates, V. vizcainoensis n. sp., occurs with a previously unknown intertidal molluscan fauna suggestive of an unprotected coastline of probable Paleocene age. Comparison of Velates vizcainoensis n. sp. to other forms previously assigned to Velates from southwestern North America suggests that “Nerita” cuneata Gabb of Late Cretaceous age probably belongs in Neritina (Dostia), as do N. (D.) aff. N. (D.) cuneata and N. (D.) escondita n. sp.

Velates is probably derived from typical Otostoma and is an early Tertiary genus. Velates californicus Vokes, although originally described as being from the Llajas Formation of middle Eocene age, is from the upper Santa Susana Formation and probably is of late Paleocene age at its type locality.

Two other neritid gastropods are present in the fauna with Velates vizcainoensis; namely, Corsania (Januncia) Janus n. subgen., n. sp. and Nerita (Theliostyla) n. sp.(?). Corsania Vidal, 1917, is a genus distinct from Otostoma and ranges from Early Cretaceous to Paleocene. Januncia n. subgen. has a Tethyan distribution and ranges from Maastrichtian through Paleocene.

Seven species belonging to three stromatoporoid genera are described from two localities at Empire Beach, southern Ontario. Stromatoporella is the most diverse genus, to which five species are assigned. The most common species is Syringodictyon tuberculatum (Nicholson), represented by ten of the twenty-four collected specimens. One genus, Syringodictyon, and one species, Stromatoporella megastrorhizifera, are new. Stromatoporella cf. S. composita Yavorsky is unassigned.

The species range in age from Emsian, or possibly Siegenian, to Frasnian. They correlate well with stromatoporoids described from strata equivalent to the lower Detroit River Group, Edgecliff Member (Onondaga Formation), as well as with the Couvinian–Eifelian horizons of Europe.

The marine Bajocian Taberna Formation of west-central Oaxaca consists mainly of shale, intercalated siltstone, and frequent iron concretions with ammonites. This formation overlies the continental Zorrillo Formation and is overlain by the continental to subcontinental Simon and Otatera formations. The best outcrops are in the area of Mixtepec and Diquiyú-Yutatio.

Two new ammonite biozones are distinguished: Duashnoceras floresi Range Zone (≃ upper Humphriesianum-lower Subfurcatum standard zones), and Parastrenoceras zapotecum Assemblage Zone (≃ Subfurcatum Standard Zone). The biogeographic affinities are principally with the Mediterranean Province, and also with both the East-Pacific Andean and North Cordilleran provinces. A high percentage of species is endemic. The Stephanoceratinae, mainly Duashnoceras, are dominant in the D. floresi Zone, which also includes Subcollina lucretia, Strigoceras (Liroxyites), Stephanoceras, Phaulostephanus, Stephanosphinctes, and Oppelia. Parastrenoceras and Leptosphinctes are dominant in the P. zapotecum Zone, whereas Oppelia and Strigoceras are less abundant.

Stephanosphinctes n. gen., type species S. buitroni n. sp., is intermediate between the Stephanoceratinae and Leptosphinctinae. The species Phaulostephanus burckhardti is also new.

A flat, thin, platelike operculum from the Antelope Valley Limestone of central Nevada fits the aperture of the shell of Palliseria robusta; abundance of these shells at the locality where the operculum occurs further supports its association with P. robusta. The operculum shows no evidence of spiral growth; its inner surface has one muscle prong. Palliseria shells are present in Nevada in enormous numbers, but opercula are known from only three localities. Because these platelike opercula are less robust than the coiled shells, most opercula may have been destroyed by wave and current movements after death of the animals.

Twenty-two specimens of Thuliocyclus prominens, a new palaeocyclid rugose coral genus and species, on a loose slab presumably from the lower Pridolian Barlow Inlet Formation at Cape Rescue on Cornwallis Island, Northwest Territories, Canada, provide a good growth series from neanic to ephebic stages. The new genus shares morphological characteristics with both typical Silurian Palaeocyclidae and more advanced Devonian Hadrophyllidae.

Early Devonian (Pragian-Emsian) rocks in the Xainza region of central Xizang (Tibet) yield a shallow-marine, carbonate-platform fauna of corals, brachiopods, dacryoconarids, nautiloids and conodonts, among which Tibetatrypa n. gen. is locally a prominent constituent. The fauna broadly resembles that of western Europe, the Altai-Sayan region, the Urals and western Qinlin province of China, but differs from the South China faunas. Tibetatrypa, related to the Silurian genus Nalivkinia, is the youngest and largest member of the subfamily Clintonellinae, and is the first Devonian brachiopod described from Tibet.

Rhondellina dorei n. gen., n. sp. is morphologically a very unusual acrotretid in possessing a marginal ventral beak and vestigial ventral pseudointerarea. In common with all other acrotretaceans it has a pitted first-formed shell that is an evolutionary novelty for the clade. By analogy with developmental stages of living lingulids and discinids it is concluded that these pitted first-formed valves are not protegula, but are larval valves developed during a protracted pelagic phase. The distinction is important in considering dispersal of the organisms. Although some acrotretids are endemic and limited to rocks deposited around a single Cambrian continental landmass, others are cosmopolitan. The wide dispersal of such forms supports earlier conclusions that the functional significance of the pits in the larval valves was an adaptation to increase buoyancy and suggests that the larvae were planktotrophic. Because of energy problems inherent with planktotrophic larvae and small parents, it is conceivable that acrotretacean development was mixed and that a relatively small number of lecithotrophic eggs were brooded prior to release of the free-swimming planktotrophs.

Rhondellina dorei was seemingly endemic to Cambrian North America. Although its larvae apparently were unable to cross oceanic barriers, the species dispersed around the periphery of the craton. It is known from western Utah and eastern Nevada and also occurs in Peary Land, North Greenland, on the opposing side of the continent. In the western United States it occurs only in the Crepicephalus Zone (lower Dresbachian, Upper Cambrian), but in Greenland it appears earlier in the upper Lejopyge laevigata Zone, in beds that are the temporal equivalents of the North American Cedaria Zone.

The genus Physaster was erected by Pomel (1883, p. 47) for Holaster inflatus of Agassiz and Desor (1847, p. 28) which d'Orbigny had first (1854, p. 89, Pl. 814, figs. 4, 5) maintained in Holaster but later (1855, p. 171, Pl. 903, figs. 1–8) transferred to Echinospatangus. Physaster inflatus (Agassiz and Desor) is the type species by monotypy. Inflataster Anthula, 1899, is an objective junior synonym derived tautologically from the same type species.

Denticle number per unit of length in the (P) element of contemporaneously occurring Ozarkodina excavata (Branson and Mehl) and O. tuma Murphy and Matti is a characteristic that shows that these taxa belong to two discrete species. Their morphological ranges with respect to this character do not overlap.

Ozarkodina tuma has a short range within the delta Zone (Lower Devonian) of the central Great Basin and is useful in intrabasin correlation.

Asymmetric sculpture in the form of tubercles or ridges on the shells of large (mean shell length ~60 mm) turritelliform gastropods has previously been shown to enhance efficiency of the shell as a penetration anchor in burrowing through coarse sediment. The small (<8 mm) turritelliform shells of all species of Argyropeza (Family Cerithiidae) have both of these ratchetlike sculptural features. Four lines of evidence from Lower Pleistocene A. divina and A. schepmaniana from Fiji support the interpretation that they help resist back-slippage: cross-orientation, frictional asymmetry, allometric shallowing, and allometric densing of sculptural elements. In addition, excellent state of preservation including protoconch sculpture, near coplanarity of aperture and ventral side of shell, and susceptibility to drilling predation by naticids support the conclusion that these gastropods burrowed in the sediment that formed the siltstone in which they are now preserved. A direct relationship is proposed between height of ratchet sculpture on turritelliform gastropod shells of approximate length range 5–100 mm and the grain size of sediments they inhabit ranging from silts to coarse sands.

Acheilus Clark, 1924, is a kingstoniid trilobite, not a catillicephalid or an unrecognizable genus as previously thought. The catillicephalid Theodenisia Clark, 1948, is here restricted to those species in which the axial furrows terminate at the 4s furrow and which lack a preglabellar furrow. Peracheilus n. gen. is proposed as a replacement name for the catillicephalid Acheilus Raymond, 1924. It includes those species previously assigned to Theodenisia in which the axial furrows continue past the 4s furrow to join a narrow preglabellar furrow. Acheilus, Theodenisia, and Peracheilus occur in the Late Sunwaptan of North America; Theodenisia also occurs in the early Ibexian.

Cellana ampla n. sp. from late Eocene rocks in Oregon is the first New World record of a genus and family heretofore considered to have radiated in Australia and the mid-Pacific. Re-examination of some other Eocene limpets from the Pacific Northwest reveals that species previously assigned to Acmaea belong in Patelloida and Siphonaria. Thus, all three major components of the modern Australian limpet guild were present in the late Eocene of western North America along a coastline occupied today by acmaeid limpet guilds. Re-examination of a large Pliocene ‘Patella’ from South America shows the shell structure of a Cellana and constitutes a second documentation of a large nacellid limpet in the New World Tertiary.

Although the taxonomy of modern limpets is founded on anatomical characters, shell structure characters are sufficient to identify genera and families directly in the fossil record. Re-evaluation and reclassification of fossil limpets using shell structure contributes not only to a better understanding of the phylogeny of major limpet groups but also provides a powerful tool for elucidating the evolutionary, biogeographic, and ecologic development of the complexly structured limpet guilds of differing taxonomic composition that dominate rocky intertidal habitats throughout the world.

Mineralogical and microstructural analyses of Quenstedtoceras shells (Callovian, Poland) show that the outer shell material is preserved as nacreous aragonite, while the septal material shows different degrees of alteration. The septa in part are pyritized or show signs of cementation by equant/acicular calcite cement; paleoenvironmental interpretation of the least-altered outer shell material using the Sr/Na ratio suggests that the shell material was deposited in seawater which had a salinity of about 33 ppt and a range of about 32–35 ppt. Other data, such as Mn and Fe, imply that the oxygen level of the seawater was normal. The paleotemperature, using δ18O values with a salinity correction, was calculated to be about 11.0–14.5°C with an average water temperature of about 12.5°C. These paleoenvironmental parameters, in part, account for the faunal character of the Boreal Realm of the Jurassic.

Oligocene landscapes of New Mexico were dominated by andesite stratovolcanoes and resurgent domes of ash-flow tuff (ignimbrite) cauldrons (Smith et al., 1985). This pervasive volcanism produced volcanic and volcaniclastic rocks that have been neglected by vertebrate paleontologists, so that, until now, no Oligocene vertebrate fossils have been discovered in New Mexico. This documents the initial results of vertebrate paleontological investigations of Oligocene rocks in New Mexico, a lower jaw of the oromerycid artiodactyl Montanatylopus matthewi, the first Oligocene mammal from the state. In this paper, CM = Carnegie Museum of Natural History and UNM = University of New Mexico.

Three distinct trilobite associations can be recognized in the Chouteau Formation (Tournaisian, Early Carboniferous) of central Missouri. These associations appear to be lithologically and environmentally sensitive. Association A, the stratigraphically lowest association, contains six genera and is among the most diverse Carboniferous trilobite associations known in North America. This association is dominated numerically by Proetides colemani and exhibits a restricted geographic and stratigraphic distribution. The association is found only in the basal 20 cm of the Chouteau Formation at one locality, in strata representing transgressive subtidal deposits. Association B is found within subtidal and open shelf lithologies and is dominated by two trilobite species, Breviphillipsia sampsoni and Breviphillipsia? swallowi. Breviphillipsia sampsoni, an apparently eurytopic species, is found in both shaly and carbonate strata but is predominately recovered from the shaly partings and interbeds. Breviphillipsia? swallowi, a more stenotopic species, occurs primarily in the more carbonate-rich intervals. In addition, five trilobite species, subordinate in numbers, are only locally common in Association B. The sparse trilobite fauna of Association C is dominated numerically by Namuropyge? armata, and is contained within open shelf sediments that interfinger with mud biostrome lithologies.

Early Carboniferous adaptive radiation of trilobites resulted from the creation of new ecospace by transgression. This allowed initially eurytopic trilobites to move into and occupy certain niches that may have been unavailable to them prior to the Frasnian extinctions. With continued deepening, niche-specialized associations developed in more offshore settings.