Interregional correlation of the marine zones of major cyclothems between North America and eastern Europe does not support assertions that a major stratigraphic gap exists between the traditional regional Desmoinesian and Missourian stages in North America. Such a gap was previously proposed to explain an abrupt change in megafloral assemblages in the northern Appalachian Basin and by extension across all of North America. Conodont-based correlation from the essentially complete low-shelf Midcontinent succession (distal from the highstand shoreline), through the mid-shelf Illinois Basin, to the high shelf of the Appalachian Basin (proximal to highstand shoreline) demonstrates that all major ∼400 kyr cyclothem groupings in the Midcontinent are recognizable in the Illinois Basin. In the Appalachian Basin, however, the grouping at the base of the Missourian is represented only by paleosols and localized coal. The immediately preceding grouping was removed very locally by paleovalley incision, as is evident at the 7–11 Mine, Columbiana County, Ohio, from which the original megafloral data were derived. At the few localities where incised paleodrainage exists, there may be a gap of ∼1000 kyr, but a gap of no more than ∼600 kyr occurs elsewhere in the Appalachian Basin at that level and its magnitude progressively decreases westward into the Illinois (∼300 kyr) and Midcontinent (<200 kyr) Basins. Thus, while a gap is present near the Desmoinesian–Missourian boundary in North America, it is typically more than an order of magnitude smaller than that originally proposed and is similar to the gaps inferred at sequence boundaries between cyclothems at many horizons in the Pennsylvanian of North America.

The hypsilophodont Oryctodromeus cubicularis from the Cretaceous Blackleaf Formation of Montana represents the first dinosaur interpreted to be from a burrow fill. The skeletal remains occurred within an incompletely preserved chamber at the end of an S-shaped tunnel. Unlike many fossil vertebrates associated with burrows, the Oryctodromeus remains were disarticulated and elevated within the graded fill. To test whether this skeletal arrangement reflected in situ burial from within or transport into the burrow, we constructed a half-scale burrow model using PVC pipes and conducted a series of sediment infilling experiments with appropriately scaled, disarticulated rabbit skeletons. Experimental trials varied incoming flow velocities, sediment supply, dry or water-filled chamber conditions, and initial placement and weight of skeletal elements. Twelve of the 13 trials resulted in complete rearrangement of the skeletons, six trials left bones elevated above the base of the chamber floor, and six resulted in graded fills. Only the trial using saturated bones preserved the skeleton largely undisturbed on the chamber floor. A trial using bones mixed with the sediment prior to deposition resulted in numerous broken elements but did not produce a distinctive bone distribution. Several trials produced bone distributions and sediment fills similar to the original Oryctodromeus burrow assemblage. The experiment as designed failed to falsify the hypothesis that the Oryctodromeus bones were in the chamber prior to burial. Experimental results include bone and sediment configurations similar to those known from the vertebrate fossil record and the former may prove useful in the recognition of burrow assemblages lacking a distinctive fill.

There is not yet a precise classification of or terminology for ecostratigraphic boundaries. SHE analysis for biozone identification (SHEBI) objectively places boundaries between abundance biozones (ABs). Alpha diversity ( = S_E  =  e^H, where H is the information function) measures the community diversity within an AB in units of effective species, whereas the dimensionless β diversity ( =  S_E2/S_E1, where S_E1 and S_E2 are the α diversities of successive ABs) quantifies the difference in α diversity between successive ABs. Three categories of AB boundary are recognized depending on the value of β. In Type –1β, the α diversity of the younger AB is significantly less than that of the older. In Type 0β, S_E2 ≈ S_E1, while in Type 1β, the α diversity of the younger AB is significantly greater than in the older. Benthonic foraminifera were sampled from the ∼124-m-thick Pleistocene strata of DSDP Hole 148 (eastern Caribbean Sea). SHEBI indicated 18 ABs; of the 17 AB boundaries, seven were Type –1β, two were Type 0β, and eight, Type 1β. The direction of inflection of the graph of lnE versus lnN did not indicate AB boundary type. Although the Pleistocene was characterized by repeated alternations between glacial and interglacial conditions, there was no regular alternation of Type –1β and 1β AB boundaries. Complementarity (i.e., species level distinctiveness of successive ABs) was measured using a percentage similarity index, C_P. Differing complimentarities show that boundaries between ABs varied with respect to permeability to species, while beta diversities and C_P were uncorrelated.

The early Pliocene sediments of the Súa Member (Onzole Formation) are spectacularly exposed along coastal cliffs in the surroundings of Súa (northwestern Ecuador). The shellbed at the base of these strata contains rich mollusk and fish assemblages and provides a rare opportunity to document the virtually unknown Pliocene shallow-water faunas of Ecuador. Stratigraphic context, faunal composition (both mollusks and fishes), biofabric trend, ichnological signatures, and taphonomic features presented here, all indicate that the shellbed is a stratigraphically condensed (hiatal) skeletal concentration generated primarily by low rates of net background sedimentation. Shellbeds of this type, immediately overlying a Glossifungites-demarcated ravinement surface, are regarded as onlap shellbeds and record landward stratal convergence and attenuation during the earliest phases of marine transgression. Although composed of largely autochthonous-parautochthonous specimens, the fossil assemblage contains mollusk species from a range of water depths and both soft- and hard-bottom habitats, implying in situ time averaging and admixture of different assemblages as transgression proceeded on a sediment-starved shoreline. The mollusk assemblage is composed of 54 taxa (26 bivalves, 26 gastropods, 2 scaphopods), and the fish assemblage of 31 taxa belonging to 16 families. Both are indicative of a well-oxygenated marine biotope swept by currents and waves, and devoid of a benthic macrophyte cover. With the exception of a few fish species and a single gastropod, the largest number of the mollusk and fish taxa are presently distributed throughout the Tropical Eastern Pacific Biogeographic Region.

Because of its fossil abundance and exceptional preservation, the Romualdo Formation of the Santana Group has become a famous lithostratigraphic unit of the Araripe Basin. In the past decades, much research has been conducted on the vertebrates of this unit, especially fish and pterosaurs, based mainly on museum collections. Despite the importance of these fossil finds, no stratigraphic information is known about them, because until recently, locals have collected most of the fossils. Here we present the results of the third controlled excavation of these layers. The data from all fossils collected confirm a faunal succession of fish biota. In the upper and most fossiliferous layer, the faunal composition shows a pattern of fish distribution never observed before, indicating that previous categories (abundance versus diversity) do not include the total diversity of fish populations. Pterosaur remains were recorded for the first time in the field, contradicting the general idea that these volant reptiles are common in the Romualdo strata. The specimen was attributed to the clade Anhangueridae because the proportional length of the first wing phalanx is less than twice the length of the wing metacarpal. The controlled excavation showed that the pterosaur assemblages from this formation probably occur in clusters. The known abundance of pterosaurs in the Romualdo Formation has been biased by just a few sites of fossil extraction, and these reptiles do not appear to have been as widespread or abundant as previously thought.

The late Guadalupian Lamar Limestone Member of the Bell Canyon Formation, Delaware Basin, west Texas, records dramatic fluctuations in radiolarian faunal composition that are interpreted to record basin-scale changes in hydrography. Samples taken across one of these intervals of fluctuation show a change from a sparse, nearly monospecific fauna dominated by Follicucullus ventricosus to a more radiolarian-rich interval dominated by spongy spumellarians of the Copicyntrinae and Spongodiscidae. Carbonate stable isotope and organic biomarker geochemical data from this same interval support a strong terrestrial-freshwater influence on the spumellarian-dominated beds. Specifically, biomarker data show lower C₂₂/C₂₇ ratios and n-alkane distributions indicative of terrestrial organic matter sources in the spumellarian-dominated beds. In the whole-rock carbonate fraction, δ¹⁸O and δ¹³C show a shift to more negative values, consistent with increased meteoric water influence in the spumellarian-dominated interval. Lithologically, the spumellarian-dominated beds are siltier; however, they lack any increase in shallow water allochems, such as sponge spicules, that might indicate the spumellarians and associated terrestrial signature are a function of transporting a shallower radiolarian fauna into the basin via turbidity flows. Faunal changes more likely represent a stimulatory response to increased runoff by in situ spumellarians in the surface waters of the basin.