A valuable fossil collection has been added to the Survey's Paleontological Collections. The new collection allows scientists to increase their knowledge of the plants, animals, and environment of the Paleocene Epoch of the Tertiary Period. The newly obtained fossils are an important addition to the Survey's already excellent and extensive collection of specimens. Many of these collections are used by scientists worldwide to study the evolution, distribution, and paleoenvironment of many plant and animal species that lived from 10,000 years to 500 million years ago.
Certain geologic intervals are not well represented in Illinois fossil collections. The Paleocene Epoch of 54.8 to 65 million years ago is one such interval. Geologists must rely on drilled cores or excavations, quarry exposures, and limited outcrops to obtain access to these buried layers of earth materials. To add to this difficulty, the Clayton Formation, the rock unit where the fossil specimens originated, exists in Illinois in only Pulaski and Alexander Counties. The Clayton Formation was deposited in a shallow ocean bay when a precursor to the Gulf of Mexico extended north into the southern tip of Illinois.
With the new fossil specimens, researchers now have access to at least 41 species of generally well-preserved Illinois marine fossils from the Paleocene Epoch. The fossils were obtained through the efforts of ISGS geologists and students and staff from the Geology Department at Southern Illinois University at Carbondale. Shark and ratfish teeth, marine turtle bones, crocodile teeth, crab claws, gastropods, bivalves, bryozoans, worm traces, and wood material—all were preserved in fossil form and recovered from a clay quarry in southern Illinois.
The new collection is particularly valuable because it contains fossil remnants of reptiles and crustaceans that are rarely found in Illinois for this time period, and because the collection was taken from a natural assemblage of fossils. Finding an assemblage that includes a great diversity of fossils along with their enclosing sediment provides scientists with key information that allows them to envision the paleoecology for this period and to understand how a wide range of plant and animal species interacted in the early Paleocene.
Updated 10/5/2009 SLD