The Ingersoll shale is a thin (~1 m), discontinuous clay lens within the Upper Cretaceous Eutaw Formation exposed on a hillslope on private property near Phenix City, Alabama. Since its initial discovery in late 2003, small-scale excavation of this marginal marine deposit has yielded an extraordinarily rich and well-preserved fossil assemblage. Thus, it is an example of a conservation fossil- lagerstatten, a deposit with unusually well-preserved fossils. The biota includes a diverse flora consisting of plant macrofossils, megaspores, and palynomorphs (including marine dinoflagellates), abundant amber, and a fauna that includes mollusks, arthropods, and vertebrates. Although many of the fossils are carbonized and/or pyritized, certain elements of the assemblage reflect unusual preservation of proteins (e.g., collagen and keratin). These proteinaceous fossils include feathers, which are extremely rare in this part of the fossil record. Within a short time, the exposure will be destroyed as a result of the ongoing housing development by the property owner. NSF funding is allowing excavation of the site to be completed in a rapid and professional manner while this important scientific resource is still available. Like other Lagerstatten, the exceptional preservation of the Ingersoll shale has the potential of making significant contributions to paleobiology and clarifying the conditions under which rare fossils are preserved. With regard to the biota itself, the flora found in the Ingersoll shale is abundant and diverse. Over two dozen genera of plants have been recognized from fossil leaves alone, some of which appear to be essentially unaltered. These can be peeled from the rock and are still somewhat flexible. Plant reproductive bodies such as seeds and cones are preserved three-dimensionally by pyritization and carbonization. Amber occurs commonly in some horizons within the Ingersoll shale, and some amber samples have yielded remains of insects and mites. Some uncompacted plant macrofossils contain in situ amber rods within them; thus, the rare opportunity exists of identifying the amber-producers and establishing plant-insect associations within a community. The feather specimens found in the Ingersoll shale are of particular paleobiological significance. Aside from the spectacular feathered dinosaurs from the Liaoning Province, China, feathers are extremely rare fossils in the Mesozoic. Known occurrences often consist of only one or a few isolated individuals, whereas the Ingersoll shale has already produced three specimens. Because amber has been shown to be the best medium for preserving feathers in detail, the possibility exists of finding extremely well-preserved specimens. Furthermore, other keratin-based tissues, such as beaks and claws/talons as well as collagenous connective tissue of the feather bearers could be preserved. Given the state of preservation of proteinaceous fossil components, further excavation holds promise for discovery of soft-bodied remains, including that of vertebrates such as feathered theropods.
