Members of the B.I.G. (Basics in Geology) group recently initiated a search for field evidence of dinosaurs in southern Illinois among outcrops of Cretaceous and related rocks and sediments found in the southern tip of the state.

Dinosaurs lived long ago during the Mesozoic era, a span of geologic time including the Triassic, Jurassic and Cretaceous Periods totaling about 185 million years. The map below reveals the general locations of rocks dating from that time period. Late Cretaceous age rocks (more than 65 million years ago) outcrop in the extreme southern part of Illinois at the upper reaches of the Mississippi embayment as shown on the map below. 

Some geologists believe it is possible fossilized dinosaur remains may someday be found in Illinois. Hadrosaur (duckbilled dinosaur) vertebrae, toe bones, and small Tyrannosaurid (perhaps Albertosaurus) teeth have already been found buried in similar Cretaceous aged sediments located just across the Mississippi River in Missouri at the Chronister Dinosaur Site. We have already started our search to find the first dinosaurs in Illinois, and discovered some very interesting exposures of Cretaceous and Tertiary/Pleistocene strata along the Mississippi River south of Thebes, Illinois (see Faulting and EQ's web page for approximate map locations). Others like Russ Jacobson and Joe Devera (ISGS) are also searching for the first evidence of dinosaurs in Illinois. Check out Dino Russ's new web page. Maybe you will be the lucky person who finds the first dinosaur fossils in Illinois. We welcome you to join us in our quest, or you can start your own search today. Please keep us informed on your progress.
	This map of North America shows the present day locations of Late Mesozoic rock outcrops (colored black). Dinosaurs lived during the Late Mesozoic era, thus this generalized paleogeography map reveals possible locations of buried dinosaur fossils. Green indicates areas occupied by lowlands and mountains during much of the Late Mesozoic. Blue areas, except the Great Lakes and upper waterways of Canada, represent seas and oceans. Notice that a small portion of these Late Mesozoic (Late Cretaceous) age sediments and rocks outcrop in extreme southern Illinois (shown in red). Do you think dinosaur fossils are buried somewhere within these Cretaceous sediments in southern Illinois? Some geologists think this is possible, and so do we. In fact we are making the hunt for dinosaurs in Illinois a BIG deal. Maybe you could join us in our search for evidence of Dinosaurs in Illinois . . . email Harvey Henson to learn more.

Hadrosauridae

The Hadrosaurs lived in Montana and Alberta where they were hatched, raised and built egg nests of their own. They traveled in large herds competing with other herbivores for local plants to eat. Fossil evidence suggests that Hadrosaurs migrated up to four months out of the year over a big part of what is today Montana and Alberta. Hadrosaur remains were recently discovered in Missouri, so it is likely they inhabited several other North American places other than Montana and Alberta.

Hadrosaurs may have even wandered across ancient southern Illinois. The paleogeographic map above indicates that much of Illinois was lowlands during the time Hadrosaurs lived (Late Cretaceous), so it is likely that they did roam across what is now Illinois. Unfortunately, almost all of the lowlands deposits have been eroded away along with any fossil dinosaur evidence from that time period.

 Some Hadrosaurs are better known as duckbilled dinosaurs, because of a wide, flat, toothless bill at the front of the mouth. Hadrosaurs were probably one of the most highly evolved herbivorous (plant-eating) dinosaurs, with continuous batteries of teeth in the mouth that gave them an even better system for processing food than Iguanodons and some present day mammalian herbivores (plant-eating mammals). The brains of Hadrosaurs are larger than those of any other herbivorous dinosaurs, and it is not surprising that there is a lot of evidence to suggest they had complex behavior.

If you are interested in joining us or learning more about the B.I.G. group, contact Harvey Henson (henson@geo.siu.edu) in the Department of Geology by phone at 618-453-7349.

 
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