The Coelophysis bonebed at Ghost Ranch, New Mexico, was discovered in the 1940s. Then, and again in the 1980s, paleontologists undertook major excavations of the bonebed. The block of Triassic rock with Coelophysis skeletons now on display at the New Mexico Museum of Natural History and Science was excavated in 1983.
The excavation began by digging above, around and under the bonebed to expose the layer of rock full of fossil bones and separate from the rock layers around it. Then, large blocks of the bonebed (each weighing thousands of pounds) were carved out and covered with wet paper encased in burlap strips soaked in wet plaster. This created a “plaster jacket” that encased the blocks of rock and their enclosed fossils, so that the blocks were held together and protected from damage while being moved to the Museum.
Heavy equipment was needed to move the blocks from the excavation site to a truck, and a bulldozer was used to do this. The block was then brought to the Museum by truck, and unloaded with a forklift.
In the Museum’s fossil preparation lab, the block was cut open and much of the plaster jacket was removed. The process of cleaning the rock away from the fossils and stabilizing the delicate fossil bones took years to complete. It was mostly done by hand, with hand tools, and some of the work was done under a microscope. This detailed and painstaking work by a fossil preparator revealed the fossil bones in the block so that they could be measured, studied, photographed and ultimately placed on display in the Museum.