A single specimen of Ratcliffespongia wheeleri n. sp. from the upper part of the Middle Cambrian Wheeler Shale in the Drum Mountains of western Utah shows two distinct skeletal layers in the limonite-replaced fragment. The probable inner layer has large, circular to elliptical parietal gaps, some of which are aligned horizontally(?); gaps are outlined by long rays of hexactine-based spicules in irregular orientation and spacing. The probable outer layer has several ranks of stauracts in regular reticulation and ranking, all at approximately 45 degrees to the probably horizontal direction. The specimen is part of a probably shallow turbidite-transported assemblage from the margin of the House Range embayment.

Microstructural and compositional data support the view that the skeletons of rugose corals consisted of (probably high-Mg) calcite, unlike the skeletons of scleractinian corals which are predominantly aragonitic. Total transformation of a late Permian rugose coral skeleton into neomorphic calcite and a significant trace element composition, however, show that aragonite was present in some Rugosa shortly prior to the extinction of this order. This finding sheds new light on the possible phylogenetic relationship between Rugosa and Scleractinia, which still possess a different mode of septal insertion and remain separated by an as yet coral-free interval in the Lower Triassic.

Two species of solitary rugose corals occur in Late Ordovician strata of the St. Lawrence Lowland. Grewingkia canadensis (Billings, 1862) appears in the upper part of the Nicolet River Formation (upper St. Hilaire Member) and is far more common in the overlying Pontgravé River Formation. A single specimen of Streptelasma divaricans (Nicholson, 1875) is known from the Pontgravé River. Their presence confirms that this area is situated within the Richmond Province and that the upper Nicolet River, as well as the Pontgravé River, is Richmondian in age. Solitary Rugosa were introduced to this biogeographic province during an early Richmondian transgression, marked in the upper Nicolet River Formation by a coarser clastic interval. That event permits correlation between the St. Lawrence Lowland in the eastern part of the Richmond Province and the North American type Upper Ordovician (Cincinnatian Series) of the Cincinnati Arch region in the western part of the province.

A comparative morphologic, paleoecologic, and biostratinomic analysis of solitary corals indicates that normal, low-energy conditions were interrupted occasionally by high-energy events (probably storms) during deposition of the upper Nicolet River and Pontgravé River Formations. Water depth increased northwestward in the St. Lawrence Lowland area. Deposition of these siliciclastic prodelta to delta front sediments was generally continuous and the sedimentation rate was usually high because of rapid basin subsidence and comparatively close proximity to the Taconic Mountains. In the western part of the Richmond Province, farther from the source area, carbonate as well as clastic sediments accumulated, periods of nondeposition were more frequent, and the sedimentation rate was relatively low. Corals disappeared from the St. Lawrence Lowland area during the Richmondian, when delta top facies of the Bécancour River Formation succeeded the Pontgravé River Formation due to a glacio-eustatic regression and progradation of the Queenston Delta.

New colonial corals from near Pittsburg Landing, Idaho, are clearly dated as Middle Jurassic (Bajocian) in age. They consist of Coenastraea hyatti (Wells) and Thecomeandra vallieri n. sp., and occur abundantly with molluscan fossils in thin, biostromal limestone beds in the Coon Hollow Formation. These fossils are the youngest shelly faunas yet known from the Wallowa terrane. The similarity of the coral and bivalve fauna to endemic faunas of the Western Interior suggests that during Middle Jurassic time, the Wallowa terrane was close enough to the North American craton for faunal exchange with the Western Interior Embayment. The Pittsburg Landing corals appear dissimilar from Middle Jurassic corals known from other terranes of the western Cordillera.

Inspection of the type collection of the Lower Silurian brachiopod Anabaia Clarke, 1899, from the Pitinga Member of the Trombetas Formation, shows that Harringtonina Boucot, 1972, is a junior synonym. Three species are recognized for this endemic Malvinokaffric Realm genus: Anabaia paraia, the type species from the Llandovery of the northern rim of the Amazon Basin and the Titicaca region in southern Peru, Anabaia paraguayensis from the Llandovery of eastern Paraguay, and Anabaia australis from the later Llandoverian through Ludlovian and possibly Pridolian in the Andean region extending from the Precordillera de San Juan, Argentina, north through Bolivia to the Titicaca region of southern Peru. It is predicted that Anabaia will eventually be recognized in South Africa, and probably in West Africa as well, in beds of Malvinokaffric Realm affinity.

A new terebratellid brachiopod species, Modestella jeletzkyi n. sp., is described from the Early Cretaceous of Prince Patrick Island, Northwest Territories, Canada. The occurrence extends the paleobiogeographic range of Modestella from northwest Europe into the northern high-latitudes of the North American continent. This new record of Modestella suggests brachiopod dispersal between northwest Europe and North America via the East Greenland Seaway, probably during the Albian. The occurrences of two other Cretaceous terebratellid genera, Advenina and Psilothyris, are updated. They are both homeomorphic with Modestella. Advenina, from the Tethyan and Jura regions of Europe, is now recorded from the Early Cretaceous of Sardinia. The occurrence of Psilothyris in North America and Europe is best explained by dispersal through the opening central Atlantic Ocean, indicating the continuation of Hispanic Corridor-type faunal links established during the Jurassic.

A new species of the late Mesozoic–Cenozoic family Ringiculidae (Ringicula (Ringicula) cockburnensis n. sp.) is described from basal glauconitic beds of late Eocene age of Cockburn Island, Antarctica, and is the first reported occurrence of the family Ringiculidae from the continent of Antarctica. Ringicula (R.) cockburnensis n. sp. most closely resembles R. castigata from the middle Oligocene Duntroonian Stage of New Zealand and provides further support for the strong provinciality (Weddellian Province) that existed along the southern margin of the Pacific during the Late Cretaceous and early Tertiary.

Modiomytilus n. gen. is described from Tertiary sediments exposed in the southwestern corner of Santa Cruz province (Argentina). This large mytilid is characterized by its ornamentation of strong comarginal undulations, its smooth ligamentary ridge, and its relatively large anterior adductor muscle. Two new species are assigned to it: Modiomytilus argentinensis n. sp., from the Centinela Formation (Miocene) south of Lago Argentino, and Modiomytilus mercerati n. sp., from the Río Turbio Formation (Eocene) in Sierra Dorotea. Although other species belonging to this new taxon and previously referred to Mytilus have been described from Tertiary sediments in the region, none are known so far from rocks of comparable age outside Patagonia.

A new genus, a new subgenus, and five new species of pterioid bivalves are described from shallow-marine faunas in the middle lower to middle Eocene Bateque Formation in the vicinity of Laguna San Ignacio to about 105 km southward, Pacific coast of Baja California Sur, Mexico. Batequeus n. gen. is a medium-sized pectinid with equally convex valves, a short byssal notch, anterior auricles smaller than the posterior ones, the left valve with numerous very closely spaced radial riblets that show the imbricated growth lines very well, the right valve with about 30 low, flat-topped radial ribs that can be grooved, and intercalary ribs on both valves. It is only known from its type species, Batequeus mezquitalensis n. sp., which is from the middle Eocene part of the Bateque Formation. Spondylus batequensis n. sp., a very spinose species, is from the middle lower Eocene part of the Bateque Formation and is only the second reported Spondylus from the lower Eocene of the west coast of North America. Pycnodonte (Phygraea) pacifica n. sp., a species characterized by a radial sulcus that originates in the umbo area, occurs in both the middle lower and middle Eocene parts of the Bateque Formation. Phygraea has not been reported previously from the west coast of North America. Pycnodonte (Pegma) n. subgen. has a plicate left valve with a large attachment area (that can cover the entire valve) and a right valve that usually has an inflated smooth central area surrounded by plicate margins. It is only known from its type species, Pycnodonte (Pegma) bajaensis n. sp., which occurs in both the middle lower and middle Eocene parts of the Bateque Formation. Cubitostrea mezquitalensis n. sp., a strongly ornamented species, is from the middle Eocene part of the Bateque Formation and is the first occurrence of this genus from the west coast of North America.

An ancestral paragastrioceratid, Svetlanoceras irwinense (Teichert and Glenister, 1952), and a specifically indeterminate gonioloboceratid, cf. Mescalites sp., from the basal Callytharra Formation are described as the oldest ammonoids recovered from the Permian of the Carnarvon Basin, Western Australia. Identity of these taxa strengthens correlation with the Holmwood Shale (Sakmarian) of the adjacent Perth Basin. Svetlanoceras moylei Mikesh, n. sp., from the Lenox Hills Formation of West Texas, is described for comparison with other simple paragastrioceratids.

A single specimen of Cyclolobus persulcatus Rothpletz (1892), a species interpreted as a primitive member of the genus, is described from the Cherrabun Member of the Hardman Formation, Liveringa Group, Canning Basin, Western Australia. It is the youngest Permian ammonoid known from Australia. Type and other representatives of C. persulcatus from Indonesia (Timor) are part of the “Amarassi fauna,” which is considered post-Guadalupian. Cyclolobus is sporadically abundant and widely distributed in the Dzhulfian Stage, and probably extends into the overlying Dorashamian Stage.

Specimens of Sphenothallus ruedemanni (Kobayashi, 1934), which were originally assigned to Serpulites, are described from the Asaphellus Zone (Tremadocian) of the Dumugol Formation, Korea. Previously, Sphenothallus was known to occur in Middle Ordovician to Permian rocks, thus making Sphenothallus ruedemanni the earliest record of this genus. This species is characterized by a distally expanding tube with smooth to variously wrinkled surface. The tube is presently composed of quartz, chlorite, and/or muscovite, which appear to have replaced calcium phosphate. The zoological affinity of this tube-building animal is still uncertain.

Sixty-five fossil brachyuran crabs, collected from rocks of the Orca Group, Tokun Formation, and Poul Creek Formation, have been assigned to six species, five of which were described previously. One of these, Pilumnoplax hannibalanus, is reassigned to Neopilumnoplax. Morphologic descriptions of Raninoides vaderensis, Eumorphocorystes naselensis, Portunites alaskensis, and Branchioplax washingtoniana are emended. Orbitoplax plafkeri n. gen. and sp. is described from the Poul Creek Formation on Wingham Island. The diagnosis of age for the Orca Group has been problematic. However, the well-preserved brachyurans, Branchioplax washingtoniana, Neopilumnoplax hannibalanus, and Raninoides vaderensis, provide corroborative evidence for an Eocene or older age for the rocks. Alaskan decapods include species common to the entire Pacific coast north of California, as well as species endemic to Alaska.

Three species of Upper Pennsylvanian crinoids, two inadunates and one flexible, exhibit a sufficiently complete growth series to describe and quantify their ontogeny. Apographiocrinus typicalis (Moore and Plummer), Erisocrinus typus (Meek and Worthen), and Euonychocrinus simplex (Strimple and Moore) were collected from the middle shale of the Millersville Limestone Member of the Bond Formation at the Charleston Stone Quarry, Coles County, Illinois. Ten other crinoid species were collected in insufficient numbers for growth studies. Both bivariate and multivariate statistical procedures were used to analyze the growth of these crinoids.

In the inadunate crinoids skeletal growth was highly coordinated in the dorsal cup and cup plates. Arm length increased by addition of secundibrachials. Food groove width increased almost three times from immature to adult stages, thus allowing a larger range of food particles to be consumed by adults. Growth of the cup is isometric in E. typus and slightly anisometric in A. typicalis. Primibrachials in both species develop anisometrically. Immature specimens possess long, slender primibrachials, with the A ray plate being longest. In maturity, the primibrachials become equidimensional and equalized in all rays. The A ray arm is followed by the C and D ray arms, and finally the B and E ray arms, in sharp contrast to arm development in disparid inadunates. Pinnules appear late in the immature stage of growth. Primary emphasis on the expansion of the arms in young inadunates demonstrates a rapid establishment of a filtration-fan mode of feeding. Subsequent development involves widening of the plates for strength and support of the arms and to accommodate wider food grooves that permit a larger array of food particles to be captured.

The flexible crinoid, E. simplex, experienced a less correlated pattern of growth. Cup plates and arms grew isometrically and all arms were added simultaneously. Development suggests that flexibles fed differently than the associated inadunates and the cup may have played a less important role in functioning of the calyx.

The upright, elevated growth pattern of stalked crinoids exposed them to a sequence of competitive interactions with other epifaunal animals that had important adaptational ramifications for their evolution, diversity, and extinction. The fact that most living crinoids, stalked and unstalked, have abandoned a permanently fixed place of growth may have been an advantageous factor in their survival.

Three ichnospecies of Bergaueria—B. perata, B. hemispherica, and B. radiata—are described from the Lower Cambrian Gog Group near Lake Louise, Alberta. Usually populations of Bergaueria are monospecific and this occurrence is unique. Since all three ichnospecies are found on a single slab, the criteria used for ichnospecies differentiation appear valid.

Enigmatic tubular trace fossils up to eight meters long occur in the Lower Pennsylvanian Middlesboro Member of the Lee Formation. Two morphotypes occur: type 1 trace fossils are plain, smooth, vertical, nonbranching, parallel-walled, tubular structures; type 2 trace fossils branch, have walls with faint vertical striations, regularly or irregularly spaced nodes, and funnel-shaped terminations. Sandstone casts filling type 2 structures have helical spiral morphology, and, in rare individuals, faint meniscate fills have been observed. Both trace-fossil morphotypes have poorly cemented wall linings containing framboidal pyrite, amorphous carbon, quartz sand, and poorly preserved fecal material.

The trace fossils occur in a massive, structureless, channel-form sandstone, originating at the contact between a channel lag and the overlying massive fill. The stratigraphic sequence is interpreted to represent a barrier island transgressing an estuarine facies. A tidal inlet within the barrier facies scoured into the underlying estuarine sediments. Subsequent rapid filling of the inlet led to the deposition of the massive sandstone.

Origin of these structures is uncertain. The preponderance of evidence favors the hypothesis that the structures are escape burrows of animals that had colonized, or were concentrated in, the lag and were suddenly buried by the deposition of the massive sand. However, no likely burrower has been identified, and several characteristics of the structures and the enclosing sediments indicate that they may be completely inorganic in origin.

Portheus patagonicus Ameghino, 1901, described on the basis of an isolated tooth from the Leonian Stage (Upper Oligocene–Lower Miocene) of Patagonia, was interpreted as belonging to an ichthyodectiform fish. Recently, the holotype was relocated and an additional tooth was found. Comparison of both specimens and some additional information permit the identification of the teeth as belonging to a delphinoid cetacean of the family Kentriodontidae. This is the first report of this family in the southern Atlantic region.

A newly discovered vertebrate fossil assemblage, the Casa Blanca local fauna, comes from the Laredo Formation, Claiborne Group, of Webb County, Texas, and is the first reported Eocene land-mammal fauna from the coastal plain of North America. The mammalian fauna is correlated with the Serendipity and Candelaria local faunas of west Texas, the Uinta C faunas of the Rocky Mountains, the Santiago Formation local fauna of southern California, and the Swift Current Creek local fauna of Saskatchewan. The vertebrate-bearing deposit lies approximately 32 m above a horizon containing the marine gastropod Turritella cortezi, which ranges from east Texas to northeast Mexico in the lower half of the Cook Mountain and Laredo Formations and is a guide fossil for the Hurricane Lentil in the Cook Mountain Formation. Nannoplankton found in these middle Eocene formations belong to the upper half of Nannoplankton Zone 16 and allow correlation with European beds of late Lutetian to early Bartonian age.

Over 700 specimens represent at least 30 species of 28 mammal genera. The Casa Blanca fauna is the southernmost and easternmost North American land-mammal fauna of definite Eocene age, and is the westernmost Paleogene vertebrate fauna from the Gulf Coastal Plain.

Medusaegraptus mirabilis Ruedemann was originally described as a dendroid graptolite and is currently listed in the Treatise on Invertebrate Paleontology among graptolites incertae sedis. Recently, several localities yielding abundant M. mirabilis were discovered, prompting renewed interest in the taxonomic affinities of this species. Based on a study of the morphology and paleoecology of M. mirabilis, this species is herein considered to represent a noncalcified dasyclad alga. Other species of Medusaegraptus are similarly considered.

Medusaegraptid-bearing strata commonly contain other exceptionally preserved fossils and represent conservation lagerstaetten. Consideration of medusaegraptids as dasyclad algae restricts the depth at which these deposits could have occurred.