Digging for Dinosaurs in Wyoming

 Late in July, 2004, my two volunteers (Robert Boscarelli and Don Pfister) and myself began exploring an area in which I had unearthed 13 articulated Stegosaurus vertebrae the previous year (late in the season and with tons of overburden needing removal before additional excavation could occur). Due to the orientation of the vertebrae, we thought we would just be lucky to find the tail spikes and a couple of back plates. We soon realized we had more work in store for us. The tail spikes were found immediately as were a few plates and then the fun began. After a week and a half of very careful excavation, we had uncovered approximately 80% of an articulated Stegosaurus. This was an amazing experience, as with every piece of rock removed another bone would appear and we followed the vertebra column back into the rock wall until we could go no further.

My volunteers left late July and I was faced with the daunting task of what to do with the bones in the ground. I decided to remove what I could and cover the remainder and leave until next year’s digging season. Good fortune soon appeared as a paleontologist arrived in the area, with an experienced digging crew, needing a place to work. Once he saw the specimen the decision was immediate … work here with me for the entire time of his stay. As you will see from the photographs, the work proceeded very quickly with an experienced crew, and the dinosaur has been fully exposed and is now being jacketed and prepared for removal from the digsite for safe keeping. We should wrap up operations in a couple of weeks and it is then back to Virginia to begin preparing the bones found this year. The Stegosaurus skeleton will be safely stored until a qualified and experienced group is found to prepare, restore and mount this wonderful specimen. The Stegosaurus has been named Sarah, in honor of the ranch owner’s daughter.

In a previous issue of the Collecting Bag, I wrote of our discovery of a virtually complete, articulated stegosaurus at our digsite in Wyoming. The digging season is over and I am pleased to report the stegosaurus has been fully excavated and is safely out of the ground and preparation will soon begin.

The stegosaurus bones were all numbered and a site map was constructed. This is crucial for a number of reasons. It is important to know where each bone was found relative to one another. The bone list, site map, and photos give valuable insight into how the dinosaur died, was buried and fossilized. Once the documentation phase was completed, the daunting task of removing the fragile bones was begun. The smaller bones were carefully wrapped or encased in plaster jackets to make sure no bone breakage would occur during transport. Since the stegosaurus was very articulated and some of the bones were either touching one another or overlapping, decisions had to be made on how to best excavate the bones with as little breakage as possible. Suitable areas for separation were located and the difficult process of digging around the bones and removing the encasing rock was begun. The bones were left on pedestals and then top jacketed with burlap and plaster. After hardening, further undercutting was performed and the bones were then given their final plaster jacket. The bones could then be ‘flipped’ in their jackets with, hopefully, all of the bones remaining intact. Sometimes, due to the overlapping nature of the bones, areas were located where we needed to cut through a bone or two to better jacket and preserve the entire specimen.

The biggest task was excavating and removing the ‘chest’ section of the stegosaurus. This section contained a major portion of the spinal column, ribs and dorsal plates. This portion of the dinosaur was too articulated to separate into smaller blocks so it was decided to remove it as one large block. We excavated around this section and then tunneled underneathe at various points and then stabilized the undersides of the tunnels. Once the entire block was completely encased in a strong plaster jacket (supported by 2 by 6 boards), it was time to lift this section onto a specially designed pallet. Using the trackhoe, chains and straps, the large plaster jacket, weighing in excess of 1500 pounds, was successfully lifted and placed on the pallet. Then the trackhoe again lifted the stegosaurus chest section and the pallet into a pickup truck for transport from the digsite. Everyone celebrated the successful ‘raising’ of the stegosaurus as after this last block had been safely removed, all that remained was loading all the jackets and boxes into an awaiting trailer for transport.

Sarah the Stegosaurus is now in the preparation laboratory of the Saurien Museum in Switzerland. Swiss paleontologist, Kirby Siber will oversee the preparation and mounting of the stegosaurus. Kirby and his crew have excavated, prepared and mounted over 10 Jurassic-age dinosaurs at his digsite in Wyoming. It will take anywhere from 2 to 4 years to prepare the stegosaurus, but the wait will be worth it for such a rare and scientifically significant specimen.