SGER: Timely Excavation of an Upper Cretaceous Fossil-Lagerstatte, Eastern Alabama

英格索尔页岩（Ingersoll shale）是上白垩统Eutaw组中的一个薄（~1米）的不连续粘土透镜体，暴露在阿拉巴马州凤凰城附近的一个私人土地山坡上。自2003年底首次发现以来，对这个边缘海洋沉积物的小规模挖掘已经产生了非常丰富且保存完好的化石组合。因此，它是保存化石的一个例子- lagerstatten，一个保存异常完好的化石矿床。生物群包括多种多样的植物区系，包括植物大化石、大孢子和巨形动物（包括海洋鞭毛动物），丰富的琥珀，以及包括软体动物、节肢动物和脊椎动物在内的动物群。尽管许多化石被碳化和/或黄铁矿化，但组合的某些元素反映了蛋白质的不同寻常的保存（例如胶原蛋白和角蛋白）。这些蛋白质化石包括羽毛，这在这部分化石记录中是极其罕见的。在短时间内，由于业主正在进行的住房开发，暴露将被摧毁。美国国家科学基金会的资助使现场的挖掘工作能够以快速和专业的方式完成，而这一重要的科学资源仍然可用。像其他Lagerstatten一样，英格索兰页岩的特殊保存有可能对古生物学做出重大贡献，并澄清稀有化石保存的条件。就生物群本身而言，在英格索兰页岩中发现的植物群丰富多样。仅从树叶化石就可以识别出二十多个植物属，其中一些似乎基本上没有改变。它们可以从岩石上剥下来，但仍具有一定的柔韧性。植物的种子和球果等生殖体通过黄铁矿化和碳化作用得以三维保存。琥珀在英格索兰页岩的某些层位中普遍存在，一些琥珀样品中还发现了昆虫和螨虫的遗骸。一些未压实的植物大化石中含有原位琥珀棒；因此，鉴定琥珀生产者和在一个群落内建立植物-昆虫联系的机会是罕见的。在英格索兰页岩中发现的羽毛标本具有特殊的古生物意义。除了在中国辽宁省发现的壮观的有羽毛恐龙外，羽毛是中生代极为罕见的化石。已知的矿床通常只有一个或几个孤立的个体，而英格索尔页岩已经产生了三个标本。由于琥珀已被证明是保存羽毛细节的最佳介质，因此有可能找到保存非常完好的标本。此外，其他以角蛋白为基础的组织，如喙、爪和胶原结缔组织也可以被保存下来。鉴于蛋白质化石成分的保存状况，进一步挖掘有望发现软体动物遗骸，包括有羽毛的兽脚亚目等脊椎动物的遗骸。

TIMELY EXCAVATION OF AN UPPER CRETACEOUS FOSSIL-LAGERSTATTE, EASTERN ALABAMAbyCharles E. Savrda and Ronald D. LewisAuburn UniversityEAR-0633839ABSTRACTThe 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.