A preliminary comparison of Early Cretaceous paleocommunities in the Caribbean and contiguous Southern Western Interior provinces of North America suggests that the important factors for the differences were climate, basinal tectonics, sedimentation rates and the resulting substrates, environmental heterogeneity, evolution rates, and migration paths. Some paleocommunities were endemic to one province, and others were found in both provinces but differed in relative abundance patterns, species composition, diversity, and trophic structure.

Bryozoans are abundant and diverse in the upper part of the Chainman Shale (Mississippian; Osagean, Meramecian-Chesterian) and in the upper Chesterian part of the overlying Ely Limestone (Mississippian-Pennsylvanian) in the Confusion Range of western Utah. The bryozoan assemblage includes 15 genera and 18 species; 12 species are new and 6 are in open nomenclature. The new species are the trepostomes Callocladia jensensis, Stenopora confusionensis, Stenoporella mineriensis, Tabulipora atacta, T. ricta, T. sarcinula, T. stragula, the cryptostomes Ascopora macellata, Rhabdomeson artum, Streblotrypa angulatum, Strebloplax pertusa, and the cystoporate Cystodictya astrepta. Species in open nomenclature are the trepostome Anisotrypa sp., the cryptostomes Saffordotaxis sp., Archimedes sp., Fenestella sp., Penniretepora sp. A, and Polypora sp. Callocladia and Strebloplax are known only from Chesterian strata in North America; Strebloplax is known only from the conterminous United States. The stratigraphic range of Stenoporella, also known only from the United States, is extended into rocks of supposed Pennsylvanian age. Stenoporella mineriensis, the only species in this bryozoan assemblage known to occur outside Utah, is also found in the Ely Limestone (Pennsylvanian) of Nevada.

Tabulipora is the dominant genus in the Chesterian rocks of this region; T. sarcinula and T. ricta are the most abundant taxa. The shallowing of the marine environment and the establishment of carbonate deposition during late Chainman time permitted widespread development and dispersal of the bryozoan faunas in western Utah.

The abundance and diversity of marine phytoplankton and the geologic timing of its major innovations and extinctions show a broad but inverse relationship to stages of terrestrial plant evolution. Successively, the first appearance of land plants, and the later major increases in global live terrestrial biomass and dead biomass in the form of plant litter, peat, coal, and soil humus, increased the retention on land of carbon, nitrogen, and phosphorus, and decreased the amount of these nutrients that was transported by rivers to the seas. Each major increase in terrestrial nutrient retention resulted in extensive changes in the marine ecosystem, as it adapted to the new conditions. From its time of origin in the early Paleozoic, the terrestrial biota figuratively occupied the position at the head of the table, and only the unutilized nutrient excess trickled down to the oceanic phytoplankton and its dependent food web.

Ammonoid faunas of late Kinderhookian (Early Mississippian) age, virtually unknown previously in the American West, are described from several localities in New Mexico, Nevada, Utah, Idaho, and Montana. This study is based upon approximately 130 specimens from 33 collections. These specimens are variously assigned to at least 15 species in the following taxa: Protocanites, Imitoceras, Gattendorfia (Gattendorfia), Kazakhstania, Pericyclus (Goniocyclus), Rotopericyclus (Rotopericyclus), and R. (Hammatocyclus). The genus Muensteroceras, once widely regarded as appearing in the Kinderhookian, is unrepresented in these collections.

The western faunas are characterized by the predominance of the pericyclids and relative scarcity of Imitoceras. Midcontinent faunas of the same age are characterized by the predominance of Imitoceras, scarcity of Pericyclus (Goniocyclus), and presence of Prodromites. Ammonoid faunas of early Osagean age differ in the presence of abundant Muensteroceras and rare Pericyclus (Pericyclus) and in the absence of Prodromites and Pericyclus (Goniocyclus).

Most of the late Kinderhookian ammonoids, both in the West and in the Midcontinent, are assignable to the Siphonodella isosticha–Upper S. crenulata Conodont Zone of Sandberg et al. (1978). A few are referable to the Lower Siphonodella crenulata Zone of the same authors. No ammonoids have been described from equivalent beds in Europe which are included in the Siphonodella crenulata Zone of Voges (1960), despite the fact that Voges regarded this conodont zone as equivalent to the ammonoid Zone CuIIa of Schmidt (1925, p. 493). Based upon conodont correlations, the American Pericyclus (Goniocyclus) fauna is middle Tournaisian (Tn2b, c) in age and, with its Midcontinent equivalents, represents a part of the section between the Gattendorfia and the Pericyclus zones of Europe, from which ammonoids are as yet undescribed.

One new subgenus is described in this paper: Pericyclus (Goniocyclus), its type species Goniatites blairi Miller and Gurley, 1896. New species described include Pericyclus (Goniocyclus) cooperi, P. (G.) costulatus, P. (G.) antelopensis, P. (G.) rockymontanus, P. (G.) filaris, P. (G.)? decipiens, Rotopericyclus (Rotopericyclus) pinyonensis, and R. (Hammatocyclus) brazerensis.

One of the richest and best preserved late Campanian-Maastrichtian ammonite faunas of the world occurs within the Lopez de Bertodano Formation on Seymour Island. The excellent exposure of this sequence has offered an opportunity for detailed stratigraphic study of the fauna, providing a stratigraphic control unavailable for most other Southern Hemisphere strata of similar age.

Ammonites are restricted to the Cretaceous portion of the Lopez de Bertodano Formation, becoming more abundant and increasing in diversity within a 600-m interval below the Cretaceous-Tertiary boundary. The ammonite-rich levels are divided into three zones (from oldest to youngest: Pachydiscus ootacodensis, P. riccardi and P. ultimus zones), extending from the late Campanian-Maastrichtian to the latest Maastrichtian.

The taxonomic study of this fauna shows a predominance of endemic taxa of the family Kossmaticeratidae, including the species Maorites tuberculatus Howarth, M. seymourianus (Kilian and Reboul), M. densicostatus (Kilian and Reboul), M. weddelliensis n. sp., Grossouvrites gemmatus (Huppe) and Gunnarites bhavaniformis (Kilian and Reboul). These taxa, together with the members of the family Desmoceratidae Kitchinites (Kitchinites) darwini (Steinmann) and K. (K.) laurae n. sp., are mostly restricted to the margins of the Late Cretaceous Weddellian Province that extended from southern South America to Australia.

Cosmopolitan genera described in this work become more abundant up section and include the species Anagaudryceras seymouriense n. sp., Zelandites varuna (Forbes), Pseudophyllites loryi (Kilian and Reboul), Diplomoceras lambi Spath, Pachydiscus (Pachydiscus) ootacodensis (Stoliczka), P. (P.) riccardi n. sp. and P. (P.) ultimus n. sp.

Extensive silicified faunules of Middle and Late Ordovician sphinctozoan sponges have been assembled from the northern part of the eastern Klamath Mountains in northern California. The sponges are from eugeosynclinal rocks that are the westernmost Middle Ordovician to Late Devonian rocks at that latitude in North America. Seventeen new species occur in the assemblages, including 10 porate and 7 aporate forms. New genera of porate forms are Amblysiphonelloides and Corymbospongia, and new porate species include: Amblysiphonella grossa, Amblysiphonelloides tubula, A. reticulata, Imperatoria mega, I. media, I. minima, I. irregularis, Corymbospongia adnata, C. mica, and C.(?) perforata. These are the first reported occurrences of Amblysiphonella and Imperatoria in the Ordovician. New aporate genera are Cystothalamiella and Porefieldia, and new aporate species include: Cystothalamiella ducta, C. craticula, C. tuboides, Porefieldia robusta, Girtyocoelia epiporata, and G. canna. This is the oldest known occurrence of Girtyocoelia, which is generally considered a Late Paleozoic form. Cliefdenella obconica n. sp. is characterized by an obconical growth form in contrast to other species of the genus that are more massive or explanate. Cliefdenella is considered here as an imperforate sphinctozoan.

Minor isolated hexactines and hexactine-derived spicules of Hexactinellida were associated with the sphinctozoans. No particular taxa within the class can be distinguished from these individual elements.

A quantitative study was made of the orientation of corals and stromatoporoids in reef core, flank, and interreef rocks representing three geological periods at eight sites, including the Florida Keys (Pleistocene), Ridgemount, Ontario (Devonian), and Pekin, New York, Maumee and Rockford, Ohio, and Bluffton and Delphi, Indiana (Silurian). Orientation, width, and height were measured for each fossil as seen in outcrop.

Fossils in Pleistocene and Silurian reef core facies have pronounced upward orientation, suggesting that most fossils are in growth location, or that the reefs were moved to their present location without appreciable tilting. Silurian distal flank facies have approximately random coral orientations, while the proximal (near-core) Silurian flank facies at Rockford has coral orientations with some upward bias. Coral width is greater than or equal to coral height (on outcrop) for 79% of the corals at all flank sites, and for 80% of the corals at the interreef site, an indicator of transport when taken with orientation data. This study permits reef facies differentiation and illustrates that fossil orientation is a useful technique for studying reefs.

During the late Trentonian the New York State region experienced gentle crustal subsidence which preceded the onset of the Hudson Valley phase of the Taconic Orogeny. The lower and middle Steuben Limestone represents several shallow-water facies: a protected shoal, a wave dissipation zone and a shallow shelf. Overlying strata of the upper Steuben and the Hillier limestones represent progressively deeper water facies. After a short period of uplift, which produced a minor unconformity, black shales began to bury the Trenton carbonate platform.

Three fossil communities are found in the upper Trenton Group. Each had been present on the Trenton bank since it first formed. The Liospira Community existed on the shallow protected shoal facies of the Steuben Limestone. Its assemblages are dominated by brachiopods, gastropods, bryozoans, and crinoids. The Encrinurus Community was found in the wave dissipation zone and on the shelf facies. This diverse community was dominated by brachiopods, bryozoans, and crinoids. The Trematis Community is found in the deeper shelf deposits of the Hillier Limestone. It was a very heterogeneous community with brachiopods, crinoids, gastropods, trilobites, and conodonts all represented.

These communities have now been traced through a minimum of eight million years of their history and it is now possible to evaluate their patterns of community evolution. At the species level these communities were quite changeable. Between 45% and 55% of the species which were present in the lower Trenton Group were replaced by the late Trentonian. Despite this changeover, the communities maintained a remarkably familiar look because there was great stability at higher taxonomic levels and the same proportions of brachiopods, bryozoans, crinoids, etc., were maintained throughout the Trentonian. Community trophic group structure also seems to have been quite stable throughout the Trentonian. If these patterns are representative, then these invertebrate communities appear to be genuinely stable entities. Evolution changes the cast of characters but the play is the same!

Scale microfossils are locally abundant in rocks of the uppermost Tindir Group and basal beds of the overlying Funnel Creek Limestone in northwest Canada. Co-occurring organic-walled fossils in this microbial mat biota resemble forms described from the Upper Proterozoic but mineralized spicules of Cambrian aspect are also present. The fossils occur in chert nodules or beds in flat laminated limestones interpreted to represent accumulation in a subtidal environment.

The scale microfossils are of three basic shapes: Group 1, simple imperforate scales; Group 2, thin disk-like scales with prominent, regularly arranged pores; Group 3, ring-like scales with distinct three dimensional morphology. All taxa in Groups 1 and 2 have scales of a single morphology and narrow size range; Group 3 taxa may contain one, two, or (?)three morphotypes and sizes of scales. The scales of Group 1 taxa are not closely comparable to known Chromophyta but are similar to scales of several modern Rhizopoda. Some of the Group 2 taxa can be compared to members of the Chrysophyta, whereas others have general resemblance to centric diatom valves. Most Group 3 taxa are morphologically comparable to members of the Prymnesiophyta. All scales that could be analyzed petrographically are now siliceous and none could be confirmed as polycrystalline.

The scale microfossils are referred to new taxa, including 17 genera, 26 species, and 6 varieties. Newly described taxa are: Group 1) Archeoxybaphon polykeramoides n. gen., n. sp., Archeoxybaphon diminutum n. sp., Archeoxybaphon amydrum n. sp., Hyaloxybaphon monokeramoides n. gen., n. sp.; Group 2) Paleohexadictyon litosum n. gen., n. sp., Paleohexadictyon myriotrematum n. sp., Paleohexadictyon coroniforme n. sp., Paleohexadictyon coroniforme var. tetragonum n. var., Paleohexadictyon coroniforme var. delicatum n. var., Chilodictyon caliporum n. gen., n. sp., Chilodictyon caliporum var. striatimarginatum n. var., Chilodictyon myriocanthum n. sp., Characodictyon skolopium n. gen., n. sp., Characodictyon skolopium var. tetragonum n. var., Characodictyon skolopium var. soleniscum n. var., Characodictyon diskolopium n. sp., Characodictyon diskolopium var. circulare n. var., Radiocerniculum inornatum n. gen., n. sp., Spinicerniculum tribulosum n. gen., n. sp.; Group 3) Petasisquama alta n. gen., n. sp., Petasisquama versicorona n. sp., Petasisquama laciniata n. sp., Bicorniculum brochum n. gen., n. sp., Confinisquama fimbriata n. gen., n. sp., Aqualisquama centritubula n. gen., n. sp., Invaginatibalteus dimorphus n. gen., n. sp., Invaginatibalteus depressus n. sp., Paterisquama crassa n. gen., n. sp., Altarmilla multistriata n. gen., n. sp., Patinisquama cirratomarginata n. gen., n. sp., Paleocrassalimbus spinosus n. gen., n. sp., and Paleomegasquama coccolithoides n. gen., n. sp.

Stromatoporoids are the major fossil faunal element of the Upper Limestone Member of the Keyser Formation in an outcrop at Mustoe, Virginia. The member is divided into four subunits at Mustoe, in ascending order: a bioherm, two biostromes, and a laminated micritic subunit. Stromatoporoids are found in all subunits, and they decrease in quantity upward. Nine species are described in three genera: Plexodictyon cf. P. waparksi Stearn, Parallelostroma typicum (Rosen), P. kaugatomicum (Riabinin), P. barretti (Girty), P. cf. P. barretti, P. keyserense n. sp., P. longicolumnum n. sp., P. multicolumnum n. sp., and Densastroma pexisum (Yavorsky). With the exception of P. barretti, a Lower Devonian stromatoporoid, the species of stromatoporids found at Mustoe have been known only from Silurian rocks in other areas.

The floras and the faunas encountered in the Mabou Mines Section of Cape Breton Island, Nova Scotia, are not greatly diversified. The floras are composed mainly of medullosean (seed) ferns referable to neuropterids and reticulopterids. Infrequently encountered are lycopod, pecopterid, mariopterid, alethopterid, fortopterid, sphenopterid, sphenophylls and cordaitean fossils. The fauna is characterized by Anthraconauta phillipsii, Carbonita spp., Leaia spp. and rare Gutschickia bretonensis representing a fresh-water, lacustrine paleoenvironment in a fluviatite regime. Shells possibly referable to Anthraconauta tenuis s.l. are rare.

In European chronostratigraphy (i.e., Heerlen), the age of the Mabou Mines Section encompasses middle to late Westphalian C to early Westphalian D. Correlation of the fauna with British chronozones is not without difficulty and a phillipsii Chronozone assignment is proposed which is somewhat lower (Westphalian C) than the floral correlation, an expected result.

A two meter stratigraphic interval within the Chowan River Formation of North Carolina contains a thicket of branching coral, Septastrea crassa (Holmes), associated with a diverse macrofaunal assemblage. The thicket modified a local shelf habitat by providing protection and feeding opportunities for certain vagrant epifaunal species. Faunal adjustments wrought by the thicket and thicket growth represent autogenic succession. Coral growth rates and preservation suggest a time span of about 100–300 years for thicket development.

Bottom shoaling, associated with a eustatic regression, caused movement of a depth controlled environmental gradient during thicket growth. As the habitat changed, a plane bottom macrofaunal assemblage replaced the thicket assemblage by reordering abundances of intergradational species and introducing a few new species. Faunal density, diversity, trophic structure, and modes of life of component species were altered during replacement.

Observed temporal community changes are best explained as gradual faunal adjustments along a shelf stress gradient. Short term allogenic or autogenic events may temporarily perturb gradual changes. Changes associated with thicket development are interpreted as a brief autogenic perturbation of long term community replacement.