Remains of animals from at least four paleoenvironments are represented at the Ellisdale Site: marine, lagoonal/backbay,
estuarine/freshwater, and terrestrial. The ecosystem was likely reminiscent of the modern
Albemarle Sound in North Carolina. Mixed faunal assemblages of this type are typically associated with transgressive lag deposits, and result from the slow accumulation of transported skeletal remains in tidal channels, backbays, and lagoons. Wave action and storms relocated the bones of marine animals to shallow water, while river currents and flooding events transported and deposited the remains of freshwater and upland terrestrial animals such as crocodilians and dinosaurs. Megafossils of at least three different types of plants have been found at the site:
Liriodendron,
Metasequoia, and
Picea. In addition, possible remains of
Mangrove roots have been found encased in siderite concretions. Amber has been found at the site occurring in small droplets, generally less than 5 millimeters in size. Taphonomic analysis of the Ellisdale fauna has revealed two distinctly different types of preservation. Bones of both marine and upland terrestrial animals are typically broken, heavily worn, and missing the outermost layer of compact bone (
periosteum). In contrast, the bones of microvertebrates such as amphibians, lizards and mammals are much more complete, with delicate processes and the periosteum intact. The small animal fauna of the site probably represents a "proximal" assemblage that lived at or near the final point of deposition, while the heavily worn bones represent a "distal" fauna. It is thought that the proximal fauna may have lived within a freshwater deltaic estuary that was affected by a coastal
storm surge or a possible
tsunami. The presence of numerous well-preserved amphibian fossils support the idea that the environment was freshwater, as amphibians are salt-intolerant. The disarticulated bones which accumulated in the lagoonal backbays by river transport, and in the shallow marine environment offshore, would have been mixed with the skeletal remains of the animals that lived within the delta as the storm surge swept over the estuary. Return flooding from the overfilled lagoons and estuarine channels after the storm's passage would have subsequently filled with debris, resulting in the mixed assemblage of animal and plant remains that are found at the site today. ==Faunal list==