Introduction

In order to familiarize ourselves with the dinosaurs found in nearby Missouri we (Joe Devera, Russ Jacobson of the ISGS, and John Utgaard -SIU) have made a number of visits to the Chronister Dinosaur Site northwest of Cape Giradeau, MO near the town of Marble Hill. We have worked on these occasions with Guy Darrough (Lost World Studios) director of the Missouri Ozark Dinosaur Project and Mike Fix ( lecturer in Geology at University of Missouri - St. Louis) at the site. By helping Guy and Mike to study the geology of this site we hope to eventually find similar deposits across the river in Illinois that also may contain dinosaur material.

Guy and Mike have developed the Missouri Ozark Dinosaur Project in order to properly deal with this site. They and other participants and members of the project have done extensive work remodeling and vastly improving the facilities and setup for this field site.

A number of late Cretaceous dinosaur and other vertebrate material has already to date been recovered from the Chronister site. Specimens found include hadrosaur vertebrae, toe bones, and small tyrannosaurid (Albertosaurus?) teeth so far in terms of dinosaurs. Also found have been several types of turtles, crocodiles, and other small vertebrates (lizards and amphibians?).

The story of Missouri's dinosaur begins in Bollinger County, Missouri, in 1942 when the Chronister family accidentally uncovered a number of unusually large bones while digging a well. Dan Stewart, a geologist who happened to be in the area at the time, persuaded them to send the bones to the Smithsonian. There, the famous paleontologist, Charles Gilmore, determined they were from the tail of a dinosaur. Unfortunately, Gilmore died shortly after and the bones were stored away and almost forgotten.

The story continues with Dr. Bruce Stinchcomb who in the 1950's when he read Gilmore and Stewart's paper as an undergraduate at Missouri School of Mines in Rolla (now University of Mo. - Rolla) became very interested in the site. Bruce from that point on had plans to eventually check into this site, and finally did so in the late 1970's. He discovered that the house on the site was no longer occupied, but the property was still owned by a member of the Chronister family - Olle Chronister, the youngest son of Lulu. Olle agreed to sell the site to Bruce. Later Bruce obtained funding from the St. Louis Academy of Science to do exploratory excavations to determine whether there were any more bones, and the extent of the bone-bearing clay. Bruce's exploratory excavations established that the clay was found widely throughout the valley, and in a number of places contained fossils including dinosaur bones.

So the story continues with Bruce proving that there was more to be found, and at this point he got others, including (to name a few) David Parris , Barbara Grandstaff, (both of New Jersey State Museum) as well as Guy Darrough and Michael Fix interested in the site. With Bruce's permission and support, Guy Darrough and Michael Fix began systematic excavations in a small quarry (now expanded to the one under the structure),

In 1999, the Missouri Ozark Dinosaur Project, Inc., a nonprofit organization, was founded in an effort to systematically excavate the site and carefully piece together a picture of what Missouri looked like in the late Cretaceous period, nearly 80 million years ago.

The Missouri Ozark Dinosaur Project is led and directed by Guy Darrough self-taught and highly accomplished paleontologist, fossil preparation expert, and illustrator who has worked in paleontology and related areas for 40 years. Guy is also owner and operator of Lost World Studios is a company specializing in the construction and fabrication of prehistoric exhibits and related subjects. Other members of the board of directors include Professor Mike Fix lecturer in Geology at University of Missouri - St. Louis, and Tom Schuessler of Jefferson College. And there are a number other members of this organization that at some point I will try to list here as I get names but who have helped with the development and success of this exciting project.

Working with some of his local partners, Guy is developing a museum in nearby Marble Hill which will house the dinosaur and other specimens recovered from the Chronister site. The museum will also become a repository for many of Guys other significant paleontological specimens. Watch this space for more information on the museum as plans develop.

For more information on the Missouri Ozark Dinosaur Project I suggest you contact Guy directly. His web pages will contain updates about the project and how you might be able to join his program to help out with this unique site in the midwest.

Geology of the Site

The fossil material is recovered from a bluish gray clay that contains the bones much of what is found here is remarkably similar to what I have found in my Hell Creek work in South Dakota.

During the past two years a clearer picture of the geology of the site has emerged as we have made subsequent visits.

What we were able to determine is that the Cretaceous (like most of the McNairy equivalents in this area of Missouri) is preserved in a downdropped fault block, called a graben. In fact we observed on one trip the edges of a fault exposed on the margins of the dinosaur quarry area where Cretaceous clays are abutting Ordovician limestones. Examinations of the quarry itself in recent visits (such as February of 2000) show extreme soft sediment contortions of the blue clays containing fossil dinosaur and other vertebrate material, which either represent drag folding along the fault zone, and/or debris flows of Cretaceous and Ordovician materials along the graben.

What happened is that the Cretaceous sediments probably covered more of the area at one time, but the formation of these downdropped fault blocks preserved this slice of Cretaceous sediment while most of the Cretaceous on the surrounding non-dropped higher landscape was eroded. This is confirmed by the presence of thinner deposits of Cretaceous on some nearby hills outside of the faulted areas, whereas it is missing largely over the region outside the downdropped blocks mapped in this region. So the occurrence and preservation of this dinosaur deposit owes alot of its existence to the faulting preserving this record of Late Cretaceous dinosaur life in this area. The history of faulting in this area is complex, and these faults were repeatedly activated, beginning during the late Ordovician with additional episodes during the Devonian, Cretaceous and Tertiary.

Since other workers in Missouri have found evidence that faulting was active even at the time of the deposition of these Cretaceous sediment it is likely that a low, maybe swampy area was formed along the faulted Ordovician limestones in the region, where thicker Cretaceous sediments accumulated in the subsiding fault block (or Graben). It may have even been a ponded environment at times (due to the lower topography of the fault block) and abundant Cretaceous turtle remains as well as remains of Cretaceous crocodilians provide evidence of this "wetlands" environment.

Joe Devera (ISGS) and I also did some reconnaissance of nearby areas and found more of these Cretaceous sediments preserved along the linear fault graben block. So there is potential for more sites even in this region alone.

We have since begun to apply our knowledge gained from this work to sites we know of in Illinois where similar clays are preserved in the McNairy, and some of them are indeed thickened in similar fault grabens slicing the underlying Ordovician bedrock. It is our suspicion that these sites preserving a thicker record of largely terrestrial swamp environments of the coastal McNairy deposits will provide the greatest potential for dinosaur material in Illinois. This spring we plan further work with some of these sites and hope we will be fortunate enough to locate dinosaur remains in them. (Dino Russ 2-10-00)

Dino Russ 10-1-01

Typical Dinosaur Material Found At the Missouri Chronister Dinosaur Site

• Typical Dino Bones This photo shows the collection of hadrosaur foot material and tyrannosaurid teeth typical of material being recovered.
• Large Hadrosaur Ungal. This is a very large ungal, perhaps one of the largest ever found according to David Norman who has seen the material.
• Large Hadrosaur Phalanx. View one. One of the large phalanxes probably from this large hadrosaur.
• Large Hadrosaur Phalanx. View two.
• Another Large Hadrosaur Phalanx. Another large phalanx from the hadrosaur.
• View of hadrosaur caudals. These small caudals are some of the more recently recovered materials from the winter 2000 field season and join a number of other caudals found in previous seasons.
• Tyrannosaurid teeth. These are probably a smaller tyrannosaurid like Albertosaurus.

• View of The Site
  • View of Missouri Dinosaur site . While not much can be seen in this early visit to the Chronister site (pits with clay and vertebrate material are flooded and need pumping). The Cretaceous clays mixed with chaotic Ordovician chert and carbonate material are seen in the cut bank on left part of photo. The current active pit (this summer again when pumped) is in foreground. The original pit at well location is below in background.
  • Here is a view (taken in February 2000) of the restored Chronister house. This was the original house of the Chronisters who found the first bones when digging a well behind the house in the early 1940's. The Missouri Ozark Dinosaur Project under the leadership of Guy Darrough, Michael Fix and a team of partners has restored this house to a rustic field station complete with running water, gas stove, firewood heat stove, and sleeping facilities.
  • View of the Chronister Dinosaur Site and facilities. February 2000. This view shows the vast improvements made by Guy, Mike and many friends and family members to this site. Besides the restored Chronister house you can see the "greenhouse" that has been built to protect the active quarry site. The small building in center was the original building to cover the quarry site until this much larger "greenhouse" was built.
  • A view from the SW side of the "greenhouse" building. This building is a well built structure that protects the active quarry site from the weather and allows the Missouri Ozark Dinosaur Project to work during winter months. Note that inside the structure suspended from the ceiling is the grid used to map the quarry operations. Later photos will show this grid from and inside view. This is one of the better grid systems I have seen at a semi-permanent quarry operation.
• Views of quarry operations, geology, and specimens
  • Suspended Gridding system. A view from just inside the door of the greenhouse structure, showing the suspended gridding structure utilized in mapping of the specimens found in the quarry. This well built suspended grid allows the crew to readily measure locations of specimens in order to preserve valuable information about where each specimen is found. Tom Schuessler, the third member of the MODP board was the builder and designer of this excellent grid with help from his wife Fern.
  • Suspended Gridding system-closeview. This view shows the numbering system used in the grid. Each grid has its grid number labeled by a suspended tag. This allows the crew member doing the mapping to readily determine the grid that the specimen falls in. To measure specimens a tape and plubbob are utilized from the suspended grid and a portable grid on adjustable legs can be utilized below the grid square allowing the mapper to precisely locate each specimen in the particular grid.
  • View of Mike Fix making measurements of quarry specimen. Mike is making measurements to determine the vertical position of the specimen in the quarry. With the amount of soft-sediment deformation found in the fault-disturbed Cretaceous sediments this vertical information is an important part of the taphonomic data collected on each specimen.
  • View of pit showing the highly irregular surface of Cretaceous clays. The red dotted line shows the irregular wavy and actually folded surface of Cretaceous clays documenting significant soft sediment deformation of the materials containing dinosaur and other vertebrate material. Large boulders of Ordovician chert and limestone can be seen scattered throughout. This complex geology is probably a result of plastic flow caused by movement along the reactivated faults and some type of debris flow related to mass wasting processes along valley walls. It appears that this blue Cretaceous clay represents a gley or wetlands soil developed in possibly topographically lower areas of the fault graben. The presence of abundant turtles exposed in this pit at the time of the photograph supports this view. The large white limestone is a piece of Plattin Limestone (Upper Ordovician) and in the valley walls behind me (probably upthrown fault blocks) contain lower Ordovician rocks of the Roubidoux Formation. This indicates a displacement of over 1000 feet! The limestone pieces are highly weathered and represent a regolith of limestone blocks formed on the Plattin Limestone surface in the downthrown graben valley where the wetlands soil containing Cretaceous vertebrates accumulated.
  • Guy Darrough, Michael Fix, and Mark Paradise (Left to right rear). Guy and Mike are leaders of the Missouri Ozark Dinosaur Project operating at the Chronister Site. Guy is a professional modeler (see his web site) producing high quality dinosaur models and displays for museums as well as a paleontologist and fossil preparator. Mike is a lecturer in Geology at University of Missouri - St. Louis. In the foreground is Mark Paradise who is a member of the Eastern Missouri Society for Paleontology, and one of MODP's volunteer workers who has been working with the project for some time helping recover many turtles from the quarry. He found 3 nice dinosaur caudals during this visit while working on the turtle to his right.
  • Dino Russ in action. I typically am taking the pictures. But this time you actually get to see me working for once :-). Mike graciously took a picture of me working on a hadrosaur dorsal vertebrae I found (with processes preserved) during my visit in February, 5, 2000. I had the pleasure and opportunity this trip of helping Guy, Mike and the crew this weekend and had a chance to help with the excavation and discovery process.
  • View of the hadrosaur dorsal vertebrae I found. Yes I know it does not look like much. The contrast between bone and sediment was poor. I have outlined the specimen in red. This was an important weekend for the project, along with this specimen 3 more caudal vertebrae with processes were found. These processes may go a long way in helping to determine the identity of the hadrosaurs from this site since no cranial material has been recovered to date.
  • Mike and his Mark uncover 3 caudal vertebrae with processes from beneath a turtle that lies towards the left corner from this hand. Turtle is broken and smeared across the surface of one of the clay softsediment folds and marked by white dots (reference numbers for later specimen preparation). The discovery of these interesting vertebrae made for some excitement for all of us. They have the processes still attached and look very interesting. We suspect more may lie beneath the turtle but this will have to wait until the specimen is removed.
  • View of the 3 caudals. Again contrast is poor so I have made red-outlines to show shape and location of specimens.
  • A view of turtle overlying the 3 caudals. This specimen is probably the most complete of many turtles currently being exposed and mapped in the quarry. Like all specimens due to the contortion and folding of the Cretaceous sediments this specimen is "smeared" and spread out along the irregular surface of blue Cretaceous clay. Part of the carapace (right of center) is relatively intact but still broken while rest is smeared to lower left corner. More of specimen is present towards the right corner. To facilitate the preparation of this specimen back in lab all individual pieces are mapped and numbered prior to removal of specimen in a series of jacket. That way the assembly of this massive jigsaw puzzle will be facilitated. The discovery of many turtles (and other wetlands environment species such as crocodiles) is important to understanding the history of this site. Turtles are very abundant (albeit broken like this) in the quarry and sometimes the recovery of these important but badly broken specimens slows down recovery of dinosaur specimens.
  • View of another turtle smeared across an inclined fold in the Cretaceous sediments.
  • Second view of this same turtle.
  • View of one of two "site watch frogs" Bud (sitting on and obscuring from view, his partner Wiser) :-). The original pit shown on my first visit was filled with water when Bud and Wiser moved into the quarry. Upon draining the quarry and construction of the greenhouse structure it was found that they decided to stay with the quarry and live in a burrow on the site of the pit.

Return to DINO RUSS's LAIR

Last Updated:5/2/07 RJJ