Boreholes in Cambrian shells are rarely reported but are a potentially significant source of information on levels of predation in early metazoan communities. This paper documents boreholes in a wide variety of Cambrian organisms. Particular attention is devoted to two species of the inarticulate brachiopod Linnarssonia (informally L. sp. A and L. sp. B) from the Middle Cambrian of southern Sweden (Brantevik, Forsemölla) and Bornholm (Læså, ⊘leå). Both successful and abortive holes occur, and both brachial and pedicle valves were attacked. Almost 20 percent of the valves of Linnarssonia sp. B from ⊘leå have successful boreholes, whereas in L. sp. A from Brantevik only 1.4 percent of the valves are bored. The proportion of successful bores in brachial and pedicle valves also varies widely, from 0.8:1 in L. sp. A (Forsemölla) to 5.8:1 in L. sp. B (Læså), although taphonomic bias caused by preferential removal of pedicle valves of L. sp. B may have distorted this ratio. The abundance and distribution of abortive holes also shows variation, with a maximum of 16.3 percent of L. sp. B from Forsemölla and a minimum of 1 percent in L. sp. B from Læså. Preference for brachial or pedicle valves among abortive holes is variable, ranging from 0.3:1 in L. sp. B (Læså) to 6.9:1 in the same species from ⊘leå. With one exception (L. sp. B from Forsemölla) successful bores always outnumber abortives, but the ratio in brachial and pedicle valves varies widely with a maximum in favor of successful bores being reached in brachial valves of L. sp. A from Læså (6:1). Boreholes are nonrandomly distributed. In L. sp. A and L sp. B successful attacks on brachial valves were concentrated in a central zone. Attacks were more scattered in the pedicle valves, although in L. sp. A boreholes tended to occur on the left-hand side. Abortive and successful bores in the enigmatic fossil Mobergella holsti, from the Lower Cambrian of Skäggenäs, southern Sweden, show a conspicuous concentration in the apical region. In addition, boreholes in Lower Cambrian material from Australia (the pseudobrachiopod Aroonia, the tommotiid Micrina) and eastern Siberia (brachiopods, and possibly echinoderms and the tommotiid Lapworthella) are reported. All these bores are attributed to the activity of predators, whose systematic affinities remain uncertain. Holes in tubicolous torellellids from northern Tamdytau, however, may alternatively represent attachment scars of other torellellids.

Small fusulinids are common in the Atokan and most Desmoinesian marine units in Ohio but less common in Missourian and Virgilian units. Twenty-one taxa are recognized. Five new species are proposed, including Millerella? elegantula, Eostaffella? recondita, Eostaffella inusitata, Pseudostaffella douglassi, and Pseudoendothyra ohioensis. Several specimens of uncertain taxonomic assignment are also included.

Approximately one-third of the previously recognized taxa were originally described from Europe and about one-half from western North America. Millerella? carbonica Grozdilova and Lebedeva, Eostaffella rjasanensis Rauzer-Chernousova, E. mutabilis Rauzer-Chernousova, and E. acuta Grozdilova and Lebedeva are reported from North America for the first time. The known ranges of several species have been extended significantly. These conclusions support the concept of a greater cosmopolitanism of Pennsylvanian foraminifers than has been generally recognized.

Organic-walled microfossils are reported from the Borden Rift Basin of northern Baffin Island and Bylot Island. The diverse assemblage, obtained by palynological acid maceration, comprises 39 taxa and occurs in fine-grained siliciclastic and carbonate units from all but the two lowermost formations of the Bylot Supergroup; their age is bracketed between 1,270 and 750 Ma. Of 307 samples analyzed from all parts of the basin, 133 yielded identifiable remains. The microbiota comprises the following taxa: Siphonophycus septatum, S. robustum, S. rugosum n. comb., S. kestron, S. capitaneum, Pellicularia tenera, Polythrichoides lineatus, Obruchevella valdaica, Karamia? sp., opaque filaments, Oscillatoriopsis spp., Palaeolyngbya sp., Arctacellularia tetragonala n. comb., A. ellipsoidea, Chlorogloeaopsis contexta n. comb., C. kanshiensis n. comb., Navifusa bacillaris n. comb., N. majensis, N. actinomorpha n. comb., Leiosphaeridia minutissima, L. tenuissima, L. crassa, L. jacutica, L. ternata, Lophosphaeridium granulatum, Valeria lophostriata, Pterospermopsimorpha insolita, Eomicrocystis elegans, E. malgica, Symplassosphaeridium spp., Synsphaeridium spp., Satka squamifera, Satka spp., Coneosphaera arctica n. sp., Coneosphaera sp., Spumosina rubiginosa, and Fabiformis baffinensis n. sp. The taxon Palaeocalothrix divaricatus, present in some macerates, is possibly a modern fungal contaminant. Abundance and taxonomic diversity varies considerably between formations and environments, with the Arctic Bay Formation exhibiting the greatest productivity and species diversity of the seven formations studied, and the transgressive muddy shelf deposits being the most productive of the 11 environments recognized. This microfossil assemblage of predominantly planktonic species has distinctive taxa in common with Middle to Late Riphean sequences in Siberia (Lakhanda and Miroedikha Groups, ca. 950 to 850 Ma), the lower part of the Thule Group (< 1,270 Ma) in northwest Greenland, the Fury and Hecla Group in western Baffin Island, and taxa reported from the upper part of the Bushimay Supergroup in Zaire. On the other hand, some elements in the Bylot Supergroup are more characteristic of Vendian beds on the Russian Platform, indicating longer stratigraphic ranges for such taxa than previously thought. The compositional similarity between the Borden Basin and Siberian sequences supports palinspastic reconstructions juxtaposing Siberia and Laurentia during the middle to late Proterozoic, and the opening of the Poseidon Ocean.

An Upper Cretaceous (early Maastrichtian) tube-building hydractinian (Psammoactinia antarctica n. gen. and sp.) from Sanctuary Cliffs, Snow Hill Island, believed to live in association with hermit crabs, is described for the first time from Antarctica. Psammoactinia forms thick, concentric, globular colonies that encrust gastropod shells and extend the shell aperture by forming an open spiral tube. The colony consists of concentric layers with chambers and pillars made of silt and very fine sand grains agglutinated by collophane, which is interpreted as a diagenetic modification of an original chitinous phosphatic material. On the basis of the additional finding of isolated claws of pagurid crabs, assigned to Paguristes sp., the functional analysis of the hydractinian structure, and a comparison with modern and fossil analogous structures it is concluded that the peculiar hydractinian tube is a carcinoecium that housed a symbiotic hermit crab.

Paleoenvironmental and paleoecological inferences suggest that the Psammoactinia–Paguristes association is mainly controlled by a fine-grained substrate and by a lack of abundant gastropod shells of different sizes. These factors do not necessarily correlate with absolute water depth, and favorable environments could include either offshore, relatively deep water or shallow restricted depositional settings.

A diverse Upper Triassic tropical marine fauna from northwestern Sonora, Mexico, includes 31 taxa of tropical invertebrates including scleractinian corals, spongiomorphs, disjectoporoids, “hydrozoans,” thalamid and nonthalamid sponges, spiriferid and terebratulid brachiopods, gastropods, bivalves, coleoids, and anomuran microcoprolites. They occur within the late Karnian to Norian part of the Antimonio Formation (Antimonio terrane), which is juxtaposed against a fragmented portion of the North American craton. Most of the fauna is also known from the Tethys region. Sixteen Sonoran taxa co-occur in the western Tethys and five have never been known outside this region. Four additional taxa (one identified only at genus level) are geographically widespread. Some taxa occur in displaced terranes of North America, especially in west-central Nevada (Luning Formation). A weak link exists with the California Eastern Klamath terrane but stronger ties exist with Peru. Among Sonoran sponges, Nevadathalamia polystoma was previously recognized only from the Luning Formation, western Nevada. Sponges Cinnabaria expansa, Nevadathalamia cylindrica, and a coral, Astraeomorpha sonorensis n. sp., are also known from Nevada. The corals Distichomeandra austriaca, Chondrocoenia waltheri, Pamiroseris rectilamellosa, and Alpinophyllia flexuosa co-occur in central Europe. Two new taxa, a spongiomorph hydrozoan, Stromatoporidium lamellatum n. sp., and a disjectoporoid, Pamiropora sonorensis n. sp., have distinct affinities with the Tethys. The geographically widespread North American brachiopod, Spondylospira lewesensis, and Pseudorhaetina antimoniensis n. gen. and sp. are among the Sonoran fauna. The Sonoran coleoid (aulacocerid) Dictyoconites (Dictyoconites) cf. D. reticulatum occurs in the Tethys realm and Calliconites cf. C. drakei is comparable with a species from the Eastern Klamath terrane. Calliconites milleri n. sp. is the first occurrence of the genus outside Sicily. The bivalves Myophorigonia jaworskii, M. salasi, and Palaeocardita peruviana are known from Sonora and Peru. Eight gastropod taxa include Guidonia cf. G. intermedia and G. cf. G. parvula, both previously known from Peru, and Eucycloscala subbisertus from the western Tethys. The gastropods are unlike those already known from other North American terranes.

The terminal Neoproterozoic Sheepbed and Blueflower Formations at Sekwi Brook in northwestern Canada have yielded two additional taxa, both of them new to North America. Hiemalora cf. H. pleiomorphus Vodanjuk is a tentaculate disc that most likely represents a semi-infaunal polyp. Windermeria aitkeni n. gen. and sp. is an ovate, bilaterally symmetrical, segmented fossil similar to the dickinsoniids; these fossils characterize Neoproterozoic faunas of Australia and the Russian Platform, but had not previously been reported from Laurentia.

The Little East Lake Formation represents a spectrum of Late Ordovician (Ashgill) nearshore environments. These physical environments are characterized by a variety of quartz- and feldspar-rich sandstone and slate. Depositional environments include neritic nearshore, beach, tidal flat, and alluvial(?). The beach and neritic nearshore environments contain a variety of fossil invertebrates. The majority of the brachiopod fauna is confined to two taxa: Eodinobolus rotundus Harper, 1984, and Dalmanella testudinaria ripae Mitchell, 1978 (in Cocks, 1978). Some of the specimens have been broken and abraded suggesting transport within the beach swash zone. Gastropods include Lophospira cf. L. milleri (Hall), Lophospira(?), Trochonemella cf. T. notabilis (Ulrich and Scofield), and Daidia cerithioides (Salter). Tidal-flat environment contains the trace fossils Palaeophycus and Planolites.

The Late Ordovician (Caradoc and Ashgill) sedimentary basins developed subsequent to the collisional Taconian orogeny, wherein an arc accreted to the eastern Laurentian margin. Prior paleomagnetic reconstructions place the southeastern continental margin of Laurentia at approximately 25° south latitude during the Late Ordovician. Using these reconstructions, the siliciclastic Ashgill rocks discussed here would have been deposited in an elongated, northeast-trending basin on the southeastern Laurentian margin. The fauna developed along this margin, but in contrast to possibly adjacent Irish and Scottish assemblages, was located in much shallower water.

In the dozen years since Alvarez et al. (1980) proposed their argument for dinosaur (and other) extinctions, lengthy debate has provided no consensus and the issue remains strongly polarized. The only test that has been proposed, that of additional fieldwork that sought to fill in the “gap” at the top of the Hell Creek Formation, recently has been conducted by Sheehan et al. (1991). Although the analysis found no indication of a gradual decline through the bulk of the formation, it did not produce the distribution Alvarez sought, a random distribution of remains clear through to the iridium. A second test based on the differing taphonomic predictions of catastrophic and noncatastrophic extinctions, and a comparison with the distribution of remains in the uppermost part of the formation, gives some credence to the latter and places considerable doubt on the former.

This paper describes a pattern recognition method, Soft Independent Modeling of Class Analogy-Modeling And Classification Using Partial least squares (SIMCA-MACUP), and demonstrates its application to two common paleontological problems—identification and prediction. SIMCA-MACUP performs statistical pattern recognition at four hierarchical levels. At level 1, SIMCA builds disjoint principal component models to characterize multivariate data patterns of several classes. At level 2, new, unknown objects are either classified into one of the classes, or recognized as outliers. At levels 3 and 4, the MACUP method models the relationship between external (dependent) variables and internal (independent) variables, and allows prediction of the values of external variables of new objects which are classified at level 2.

The applicability of the SIMCA-MACUP has been demonstrated in a case study of the Pliocene planktic foraminiferal clade Globoconella. Two morphotypes of the clade Globorotalia (Globoconella) puncticulata and Globorotalia (Globoconella) inflata were characterized in a reference sample with SIMCA. Ancestral forms of the two morphotypes were traced through the early phylogenetic history of the clade, resulting in a reconstruction of the branching pattern of the divergence of G. inflata from G. puncticulata. The apertural height and apertural width of specimens in the ancestral stocks were then treated as if there were two “external” variables, and predicted using MACUP. The predicted values show slight discrepancy from the observed values. The deviation is size-dependent, indicating a decoupling of the apertural shape from the size of foraminifers during the branching process.

A complete morphologic intergradation from biperforate to multiperforate specimens of Nephrolithus frequens Górka (1957) occurs in the uppermost Maastrichtian chalk at southern high-latitude ODP Holes 750A (Kerguelen Plateau, southern Indian Ocean) and 690C (Maud Rise, Weddell Sea). Previous workers have assigned taxonomic importance to the number of pores of the central area. Two subspecies, N. frequens subsp. frequens and N. frequens subsp. miniporus, were recently differentiated (Pospichal and Wise, 1990) based on this character (four or more pores and two pores, respectively). The observation of specimens of Nephrolithus frequens with three pores in the central area indicates that there is no “natural” breaking point in a progression from two to numerous pores and that specimens of N. frequens with different pore numbers should be considered morphotypes of a single species exhibiting a high intraspecific variability. In addition, our observations using the scanning electron microscope and light microscope illustrate that in well-preserved specimens each pore in the central area is surrounded by two cycles of elements. The margin consists of two cycles, with the elements of the inner cycle extending proximally about twice as far as the elements of the outer cycle.

A deep core from Warren County, Ohio, has yielded numerous fossils of Cambrian age. The specimens, which are among the first recorded from Cambrian rocks of Ohio, suggest revisions in the inferred ages of the Eau Claire and Mount Simon Formations in the Cincinnati Arch region. Trilobites indicative of Dresbachian (late Middle Cambrian to early Late Cambrian) and possibly Franconian (Late Cambrian) age are present in the upper Eau Claire Formation. By implication, the underlying Mount Simon Formation must be of earlier Dresbachian age or perhaps older. Identified trilobites from the Eau Claire Formation seem to be characteristic of inner-shelf lithofacies of Laurentia. Other body fossils from the Eau Claire Formation include inarticulate brachiopods and a graptolite. Body fossils in the lower Knox Dolomite include trilobite sclerites and echinoderm ossicles. Trace fossils are present in both units.

A preliminary survey of benthic invertebrates off central west Florida provides documentation of modern epifaunal communities on a low-gradient carbonate slope. Three large-scale biofacies occur in soft-sediment carbonate environments between 200 and 2,000 m: an Echinoderm biofacies (200–550 m) dominated by a diverse assemblage of echinoderms, gastropods, and decapod crustaceans; a Penaeid shrimp–conical mound biofacies (550–1,200 m) characterized by large bioturbation structures; and a Microbial mat biofacies (1,200–2,000 m) with only rare epifaunal invertebrates. A fourth, hard-substrate biofacies reflects the presence of localized Miocene and Pleistocene hardgrounds in water depths of 200–600 m. This illustrates that hard-substrate biofacies may be laterally correlative with soft-sediment biofacies in a slope setting, thus producing a mosaic of contrasting faunal associations. All four biofacies have low population densities, presumably as a consequence of relatively low surface productivity. All four biofacies also show biogeographic affinity with other faunas at intermediate depths in the Caribbean region. Depth-related faunal transitions on the west Florida slope correlate with substrate and current velocity. Decreasing species diversity and abundance and a biofacies transition from suspension-feeding to deposit-feeding assemblages correlate with increasing depth, a decrease in mean grain size, and an increase in organic content of the sediment. This biofacies model may provide a modern analogue for faunas of ancient low-gradient slopes such as those of Cretaceous “shelf-sea” chalks of northwestern Europe.

Rugose and tabulate corals from the Lower Permian (Wolfcampian) part of the Bird Spring Group in the Providence Mountains, San Bernardino County, southeastern California, comprise eight species in eight genera. Heritschioides mckassoni n. sp. is the lowest stratigraphic record for this index genus on the undoubted shelf of western North America. Paraheritschioides applegatei n. sp. is the first record for the genus in southern California. Neomultithecopora providensis n. sp. is a second species for the genus in the southern Great Basin. The other five species provide close ties to previously described faunas from the Spring Mountains and the Arrow Canyon Range of southwestern and southeastern Nevada. The combined Wolfcampian coral faunas of these three areas are somewhat closer at the genus and species level to the McCloud Limestone Wolfcampian faunas of northern California than to the Wolfcampian shelf faunas in east-central Nevada. Additional species present in the combined faunas are known originally from the Wolfcampian of central Nevada and Kansas and a genus is not otherwise known south of British Columbia. The faunas suggest a subprovince of the Durhaminid Coral Province for the southern California and southern Nevada area and perhaps imply partial isolation from the more northerly parts of the province by land barriers such as the Antler Highlands.

Solitary species of Heliophyllum are the most common form of the genus but branching and massive colonies do occur, especially in Middle Devonian strata of eastern North America. Heliophyllum delicatum n. sp. offsets laterally and has a dendroid, broad bushy growth form. The species is known only from western and west-central New York and appears to be limited to the lower part of the Deep Run Shale Member of the Moscow Formation (middle Givetian); specimens are common within this restricted geographic and stratigraphic range. The skeleton of H. delicatum was poorly designed for the common coral environments of the Devonian, but seems to have been well adapted to muddy, carbonate-poor conditions where its thin skeletal elements required less calcium carbonate and its unsupported branches were not subject to vigorous water movement.

Heliophyllum stewarti n. sp. is based on a single specimen from the Tenmile Creek Dolomite (middle Givetian) in northwestern Ohio. The colony is phaceloid but each branch is an astreoid cluster without walls between individual corallites. In addition, the apparent protocorallite is turbinate with a larger diameter than any of the ceratoid offsets although offset lengths are several times that of the protocorallite.

Species-level taxonomy of fenestrate cryptostome bryozoans has been greatly advanced by a recent study of the fenestrate fauna of the Warsaw Formation (Osage–Meramecian) of the Mississippi Valley; subsequent quantitative analysis placed the earlier research on a sound statistical basis. Reproducibility of these results is tested here, and it is demonstrated that subsequent researchers can duplicate earlier data collection and results. The methodology is then extended in space and time to a second fenestrate faunule (Virgilian of east-central Kansas); morphs within two traditionally defined fenestrate species are successfully distinguished.

Lithologic characteristics of the two Virgilian study units suggest differences in depositional environments between the horizons and therefore simple ecophenotypy and intraspecific variation cannot be dismissed. However, chamber dimensions, which provide the most sensitive characters for taxonomic discrimination, change in parallel for the two species, whereas exterior skeletal dimensions, which would presumably respond more readily to microenvironmental fluctuations, vary nonsystematically between populations. These results provide a starting point for the evaluation of morphologic change within fenestrates through stratigraphic and paleoenvironmental sequences. Cumulative data sets spanning long time intervals would allow evaluations of evolutionary histories among members of this important Paleozoic clade.

Microforaminiferal linings assigned to 10 known genera have been recovered from Early Devonian (Lochkovian to Late Emsian) limestones from Victoria, New South Wales, and Queensland. These organic linings have been identified by comparison with normal-sized agglutinated foraminiferan genera known to occur in the associated sediments. Microforaminiferal linings with smooth walls and reticulate sculptured walls were present and the possible implications of these (diagenetic, relict structure, naked homeomorphs, or processing artifact) are discussed. Evidence is presented that Ordovicina may have a bilamellar organic wall lining.