Seymour Island, Antarctica (64°17'S), offers the first opportunity to examine the crisis at the end of the Cretaceous from the high southern latitudes. The K/T boundary sequence on Seymour Island consists of a nearly continuous sequence of siliciclastic sediments deposited in a mid-shelf environment. The faunal changes across the boundary occur through a 30-m interval with no single extinction horizon, in contrast to other well-studied K/T boundary sections. The “expanded” nature of the Seymour Island section makes placement of the K/T boundary difficult because boundary indicators such as planktic foraminifera, ammonites, and dinocysts disappear at different levels within the section.

The lowest Cambrian of Avalon, or Placentian Series, is a relatively thick sequence (1,400 m) in southeastern Newfoundland. A newly proposed body fossil zonation supplements an existing trace fossil zonation of the lower part of the Placentian Series and includes strata to the top of the sub-trilobitic Lower Cambrian.

The Sabellidites cambriensis Zone brackets the Precambrian–Cambrian boundary and comprises peritidal and wave-influenced subtidal facies deposited during deepening through the lower part of the Chapel Island Formation. Younger “Ladatheca” cylindrica Zone strata include the deepest facies of the Chapel Island Formation. The base of the overlying Watsonella crosbyi Zone (a post-Nemakit Daldyn and pre-Tommotian equivalent) is significantly diachronous because the diagnostic mollusks were preferentially preserved in pyritiferous offshore muds rather than in coeval nearshore muds. High diversity, upper Watsonella crosbyi Zone faunas (18 species) are limited to peritidal limestones of member 4 and are dominated by calcareous small shelly fossils. A thick interval (ca. 430 m) without body fossils and an important episode of block faulting that led to 750 m of differential erosion preceded deposition of the lower part of the Bonavista Group (=Sunnaginia imbricata Zone, an interval considered to be largely older than the Tommotian). Although much Early Cambrian time may be lost as a result of erosion at Random Formation–Bonavista Group unconformities, many Watsonella crosbyi Zone species reappear in the Sunnaginia imbricata Zone. Shoaling accompanied the immigration event defining the base of the Camenella baltica Zone, and an unconformity following regional offlap marks the top of the Placentian Series.

Calcareous, and not phosphatic, composition is most common in earliest Cambrian shelly remains. Little evidence suggests that a global, Precambrian–Cambrian boundary interval “phosphogenic” event either resulted in deposition of local phosphate deposits in the Tethyan region or had a role in the appearance of mineralized skeletons.

Twenty metazoans and problematica and an alga are illustrated from the Chapel Island Formation. Bemella? vonbitteri Landing n. sp. and Halkieria stonei Landing n. sp. are described. The monoplacophoran Archaeospira? avalonensis Landing n. sp. has right-and left-handed conchs comparable to those of Archaeospira (=Yangtzespira) from China. Anabarites is the senior generic synonym of Tiksitheca.

The foraminiferal suborder Astrorhizina is reinstated for the typically monothalamous agglutinated taxa whose cementing material is solely organic, the suborder Haplophragmiina reinstated for multilocular agglutinated taxa with organic cement and simple to alveolar walls. The suborder Trochamminina is recognized for those with organic cement and simple agglutinated walls, and the suborder Textulariina is restricted to include only those with agglutinated walls containing biogenic calcareous cement, and typically canaliculate. In the latter suborder, the new genera Connemarella, type species Gaudryina rudis Wright, and Hemlebenia, type species Hemlebenia aptiensis n. sp., are described in the expanded family Pseudogaudryinidae, subfamily Pseudogaudryininae, whose geologic range thereby is extended into the Lower Cretaceous (Aptian).

Inozoans are described from patch reefs on the carbonate platform of eastern Sichuan, from the uppermost Permian Laolongdong reefs in the Changxing Formation (Kazanian–Tatarian) at Beipei, northwest of Chongqing, and from Middle and Upper Permian reefs from the Maokou (Kungurian), Wujiaping (Ufimian), and Changxing Formations at Xiangbo, Longlin County, in northwestern Guangxi. Classification of inozoans, particularly late Paleozoic ones, is still in a state of flux, but genera recognized to date can be keyed using the general nature of the spongocoel, canals, and growth form.

New genera described are Intratubospongia, Grossotubenella, Cavusonella, and Radicanalospongia. The new species described are Stellispongia radiata, S. minor, Peronidella beipeiensis, P. regulara, P. parva, Intratubospongia typica, I. tenuiperforata, I. multisi-phonata, I. minima, Grossotubenella parallela, Cavusonella caverna, and Radicanalospongia normala. A Corynella that is not identifiable to species and a sphinctozoan-like inozoan(?) sp. A that has a fibrous-appearing internal skeleton but is poorly preserved are also described. Inozoans and other sponges are major frame-builders in the Permian reefs of South China and our fauna is one of the most diverse late Paleozoic assemblages described to date.

Twenty-one species of corals and three species of spongiomorphs occur in a series of richly fossiliferous, molluscan-dominated beds with silicified bioclasts in the Upper Triassic Martin Bridge Limestone of Hells Canyon, Oregon. Two of these, Maeandrostylis grandiseptus and Recticostastraea wallowaensis are new species. Recticostastraea is designated as a new genus.

The fauna is early Norian and occurs in the island arc Wallowa terrane, one of many tectonostratigraphic terranes in western North America. Like other examples, it appears to have developed independently of the North American craton and to have links with Wrangellia. The fossil corals and spongiomorphs are para-autochthonous, occurring in a series of tempestite beds. They are interpreted to have inhabited a shallow-water carbonate platform that developed around a tropical island arc following cessation of volcanic activity. The corals and spongiomorphs are associated with abundant gastropods and a diverse epifaunal suspension-feeding bivalve fauna. Relative to the corals, branching spongiomorphs, Spongiomorpha ramosa, are more abundant and occur with relatively common branching, sheet to plate-like, colonial corals. Solitary corals are relatively rare. The associated bedded limestone includes a variety of shallow-water microfacies but throughout the Hells Canyon sequence, reef structure is absent.

Together, the 24 coral and spongiomorph taxa show mixed paleogeographic affinities with Upper Triassic faunas known only from alpine regions of the western Tethys (five species), the Pamir Mountains, U.S.S.R. (two species), and the island of Timor (one species). Five additional species are pan-Tethyan and exceptionally cosmopolitan, but 11 species (45.8%) occur only in displaced terranes. Of these, a significant component (six species) is endemic to the Wallowa terrane. At least four Hells Canyon taxa, previously thought endemic to North American terranes, have recently been reported from the high-latitude Koryak terrane of northeastern U.S.S.R., a displaced tropical volcanic terrane of the northwestern Pacific. For Triassic corals, this is the first example of a clear link between western Pacific and eastern Pacific terranes. Less similarity exists with the Wrangell Mountains, Alaska, where identical age lower Norian silicified corals and spongiomorphs are known.

Specimens representing Heliolites diligens Bondarenko, 1966, H. aff. H. luxarboreus Yang, 1978, and H. tchernyshevi Bondarenko, 1966, are common and Heliolites sp. and Stelliporella sp. are rare in diverse coral assemblages associated with lithistid sponge reefs in deep shelf or ramp limestone facies of the Douro Formation. Heliolites diligens, a more widely adapted, possibly “opportunist” species, occurs abundantly in lower diversity stromatoporoid/coral assemblages from nonreefal, shallower shelf limestone facies. Detailed systematic study of approximately contemporaneous populations of these Ludlovian heliolitid species shows that all are morphologically variable; assessment of this variability qualitatively and quantitatively is critical to species definition and recognition. Heliolites diligens is the most variable, with wide intercolony variation in septal development, corallite wall configuration, and spacing of horizontal skeletal elements. This apparently represents morphological plasticity rather than differences that can be ascribed to distinct species. Conspecificity of the more extreme and dissimilar variants can be inferred from study of large assemblages of coeval specimens. The other species, with more narrowly defined, discrete variation fields, are more readily distinguished from each other.

Rostroconchs are a common faunal component in the Devonian rocks of Ohio, particularly in the Columbus and Dundee Limestones. Hippocardia cunea (Conrad) is the most abundant species. Also present are H. monroica (Grabau), H. ohioense (Meek), H. curta n. sp., and Bransonia? sibleyense (La Rocque).

Growth series of Hippocardia cunea show that the large hood and the rostrum begin to develop early in ontogeny. The rates of increase in the number of comarginal growth increments on the posterior or rostral face and radial ribs on the body of the shell are slow; most size increase of the shell occurred in the increasing widths of the ribs and the interspaces. The length/height ratio increases from young to juvenile specimens and then decreases in adult specimens. However, the length/width and height/width ratios show a general decrease from young to adult specimens. Considerable variation in shell lateral profile is present in H. cunea.

Three specimens of Hippocardia cunea show borings entering the posterior rostral portion of the shell, presumably made by Trypanites, a polychaete worm. In one instance, a boring caused disfiguration of the shell material indicating that the host was alive at the time of the boring. The orientation and location of the borings and the presence of one specimen believed to be preserved in life position provides the base for interpreting H. cunea as an infaunal deposit feeder.

Waldemaria monticola Pierce n. sp. and “Hendersonia” valida Pierce n. sp. are described from fluviatile sediments of the intermontane Flint Creek Basin of western Montana. The genus Waldemaria was previously known only from Japan. The presence of these two genera suggest a marked climatic cooling when compared with western North American Eocene–Oligocene faunas. The stratigraphy of the Flint Creek beds, and the associated vertebrate fauna, diagnostic of an early Barstovian age (17–15 Ma), is summarized.

Lapparia sp. A of Toulmin (1977), from the early Eocene Hatchetigbee Formation of Alabama, is referable to the Tethyan genus Volutilithes and is conspecific with Voluta clarae Harris. This is the first certain record of Volutilithes in the Paleogene of the Gulf Coastal Plain and only the third record of the genus in North America. Trans-Atlantic migration of this tropical genus to the New World apparently occurred during the early Eocene. Its northward expansion into the higher latitudes of Alabama and southern California was probably in response to early Eocene climatic warming.

In addition to Volutilithes, many other molluscs with Tethyan affinities are present in the Paloegene deposits of the Gulf Coastal Plain. These Tethyan elements, however, differ from those reported from the Eocene of peninsular Florida. The presence of a filter-bridge barrier, the Suwannee Channel, between the eastern Gulf shelf and the Floridian carbonate platform during the Paleogene may account for this difference.

Trilobites assigned to the Elvinia Zone (Lower Franconian, Upper Cambrian) have been recovered from the Collier Shale in the Ouachita Mountains of west-central Arkansas. The trilobites are preserved as disarticulated exuviae, and are found in both dark-colored limestone clasts and dark, thinly-bedded carbonate layers. Field observations and petrologic/petrographic evidence indicate that these trilobites were originally deposited in a deep-water, outer shelf setting, and that shortly after deposition they were transported by sediment gravity flows to the continental slope or basinal plain.

The faunal assemblage is very similar taxonomically and taphonomically to faunas of the Elvinia Zone previously reported from North American shelf environments. Two distinctive trilobite assemblages occur in the Collier Shale. Most common is a diverse fauna that is correlative with the middle to upper part of the Elvinia Zone in Missouri, Oklahoma, and Texas. One locality yielded numerous trilobites characteristic of the Irvingella major Subzone, which occurs at the top of the Elvinia Zone in these areas. These Elvinia Zone trilobites belong to the North American Faunal Province, a largely endemic group restricted to shelf environments around the perimeter of the North American craton. Their occurrence in the Collier Shale strongly indicates that the original site of Collier deposition was proximal to the Upper Cambrian shelf margin and that the Ouachita sedimentary section is not an exotic terrane.

More than 7,900 trilobites were identified during this study; they are assigned to 26 genera and 27 species. The family Cliffidae is proposed for a group of trilobites that includes species of Cliffia Wilson, Aphelotoxon Palmer (junior synonym Ponumia Hu), Drabia Wilson, and possibly Elyaspis Kurtz. Three new genera are erected (Kymagnostus, Pyttstrigis, and Jessievillia) and 10 new species are described and illustrated (Apachia genaitholix, Cliffia magnacilis, Dellea planafrons, Iddingsia hapsis, Jessievillia radiatus, Kymagnostus harti, Neoagnostus? dilatus, Aphelotoxon lumaleasa, Pulchricapitus fetosus, and Pyttstrigis dicilia).

A new Fourier method is presented to quantify shapes too complex to be described by conventional polar Fourier analysis. The length along a closed curve serves as the independent variable. The centroid of the curve is determined and for each point on the curve two different dependent variables are defined, based on: 1) the angle defined by the starting point, the centroid, and the point on the curve; and 2) the radial distance from the centroid to the point on the curve. The method is used to describe the trilobite cranidium, and 12 harmonic coefficients are found to summarize 99 percent of the shape information contained in the cranidial outline. In an application to trilobite evolution during the Cambrian and Ordovician, it is found that higher taxa of trilobites become progressively more distinct morphologically. This result is in agreement with previous qualitative observations, and is attributable to an increase in morphologic dispersion among higher taxa, but not to a decrease in morphologic dispersion within higher taxa.

Paolia vetusta Smith, 1871a, from the Hindostan whetstone beds of Indiana (Namurian), thought to have been lost since 1918, has been found and currently is housed at Hanover College, Hanover, Indiana. Paolia vetusta is illustrated photographically for the first time. The major character difference between Smith's (1871a) figure and the actual specimen is the lack in the latter of an extensive archedictyon extending over the entire specimen. Currently, the family Paoliidae is defined as having Sc terminating on R. Paolia vetusta clearly shows Sc terminating on C. Therefore, the Sc terminus should have no taxonomic significance at the family level.

Flume studies conducted on models and specimens of the helically twisted columns from Mississippian platycrinitid crinoids revealed two unique hydrodynamic interactions. Water is deflected up the column from levels near the sediment-water interface where food particles are more abundant. Turbulence, both in the lee and on the upstream side of the column, removes nutrient-poor water and replaces it with nutrient-rich water from near the sediment-water interface. Subsequently, the nutrient-rich water would have been filtered through the feeding apparatus of the crinoid. An upward deflection of as little as 10 percent bottom water would have resulted in a substantial increase in food particle load. Thus, the form of platycrinitid columns gave the crinoid a feeding advantage over otherwise similar crinoids of the same time period. The most diverse and abundant group of Mesozoic–Cenozoic stalked crinoids shows similar column modifications which suggests that the morphology may impart some competitive advantage to the organism.

A specimen of the unstalked Cretaceous crinoid Uintacrinus socialis Grinnell, 1876, has a theca with an anomalous appearance that may be attributed to either inaccurate regeneration or unusual taphonomy. The former would entail regeneration of brachials from pinnulars, and inaccurate regeneration of the arms themselves. The latter would imply that the theca was broken into at least three pieces, and then the pieces were rotated with respect to each other. The presence of broken plates and sediment in the line of breakage indicates that the specimen was broken after death, and the taphonomic explanation is favored. Of the hundreds of known specimens of this species, this is the only one with such an appearance.

The Somerset Shale Member (Mississippian: Valmeyeran) is a discontinuous shale at the base of the Salem Limestone in southern Indiana and central Kentucky. It is the only significant terrigenous unit within a thick sequence of shoaling carbonates deposited on the eastern side of the Illinois Basin over the Borden Delta siltstones. The Somerset Shale contains a diverse echinoderm fauna of blastoids (five species), crinoids (20 species), and echinoids (two species). Most of the species are known only from the Somerset or from carbonate rocks directly above and below the Somerset Shale. There remains a small number of species previously known mostly from terrigenous rocks (the Borden Delta) below the carbonates. This demonstrates that at least some of the faunal differences between the Borden crinoids and those of the overlying carbonates are the result of paleoecologic factors. The Somerset Shale may mark a useful biostratigraphic boundary defined by last occurrences of the genera Barycrinus, Cyathocrinites, and Actinocrinites and the base of the range of Batocrinus. The species Batocrinus somersetensis n. sp., Dizygocrinus calvus n. sp., and Barycrinus punctus n. sp. are described.

Upper Ordovician flysch of the Matapédia Group of New Brunswick, eastern Canada, contains many examples of burrows that possess an upper meniscate portion and a fecal pellet-packed lower portion. A new ichnogenus, Compaginatichnus, is proposed for these burrows and its type ichnospecies, C. forbesi, is described in detail.

A newly discovered locality of aestivation burrow casts containing the lungfish, Gnathorhiza serrata, is reported from the early Permian Arroyo Formation of Wilbarger County, north-central Texas. Remains preserved in the burrow casts provide sections of mummified Gnathorhiza and new information about the postcranial skeleton of this fish. Scales of Gnathorhiza resemble those of the modern lungfishes such as Lepidosiren in their microanatomy. No traces of paddle-like pectoral or pelvic fins were found and paired fins of Gnathorhiza may have resembled those of Lepidosiren. The axial skeleton and median fins of Gnathorhiza seem to resemble those of Lepidosiren except that the tail area and caudal fin of Gnathorhiza were stout and strong rather than slender and tapering. Gnathorhiza, which aestivated tail-down in its burrow, may have required a stout tail for support.

New specimens of Shastasaurus altispinus Merriam are recognized from the Upper Triassic Antimonio Formation in the El Antimonio district of northwestern Sonora, Mexico. This represents the first occurrence of the species outside of its type locality in Shasta County, California, and the first known occurrence of Triassic ichthyosaurs from Mexico. Some remains are well preserved, but in general they are fragmented, structurally distorted, and incomplete; however, they enhance the current understanding of the morphology of a species that has been known hitherto only from an even more incomplete holotype. The material is the first from any Shastasaurus that preserves the anterior portions of the skull and lower jaw and implanted teeth. Revised diagnoses for the genus and species are given on the basis of the new material. Biostratigraphic zonation furnishes an early Late Carnian age for the specimens, which is in accord with that for the holotype.

Fossil bird bones from the late Eocene Keasey Formation and the latest Eocene Pittsburg Bluff Formation in northwestern Oregon are the earliest records of the pelecaniform family Pelagornithidae for the Pacific Basin. These fossils also represent the first late Eocene records of the family from the Northern Hemisphere, the second late Eocene record worldwide, and indicate that these animals were among the largest of flying birds. Unfortunately, the fragmentary condition of these fossils and the currently confused state of pelagornithid systematics prevents the assignment of these specimens to new species at this time.