Most fossils form when minerals seep into bones, slowly turning them to stone. Soft tissues, such as skin and muscles, break down. But in the nodosaur’s case, minerals hardened around its body like a shell (see Fossil Formation, below). This kept the skeleton from being crushed and protected the soft tissues from decay. Millions of years later, the dinosaur’s scaly skin and spiky armor are still intact.
Freeing the nodosaur from the ground wasn’t easy. It took workers 17 days just to carve it out with their machines. Most of the body was still encased in rock.
Mark Mitchell, a technician at the Royal Tyrrell Museum, worked on the fossil. He had to remove the rock carefully to avoid damaging the delicate skin and bones inside. After gently chipping away each bit of rock, he would squeeze a drop of glue onto the dinosaur to hold it together. The process took him six years! In early 2017, the fossil was finally ready to be studied.