Once the skeleton has been exposed, the next phase is to catalogue what is there. A site map is drawn. This is a plan of the site showing where each bone lies, and the presence of anything else that may be of interest. Only when all this has been done can the excavation begin.(Animatronic Dinosaur Equipment) Fossils that are newly exposed to the air may be very fragile. They may he unstable, and chemicals in them may react with the atmosphere and cause the fossil to decay quickly. Exposed hones are treated as quickly as possible with a chemical or varnish to seal them, and stop the air causing deterioration. The exact nature of the chemical or varnish has to be recorded for the technicians at the laboratory or the museum.
Fossil hones can he so fragile that they crumble away if they are lifted. (walking dinosaur costume)To avoid this, they arc encased in a jacket. It consists of a layer of moist paper, then a layer of plaster bandages – just like the plaster cast used in medicine for repairing a broken limb. (In the clays of the “bone wars’’, (Animatronic Dinosaur)this technique was pioneered by a fossil hunter, using rice, the staple food of the expedition.) The exposed part of the hone is covered in rhis plaster jacket. Then the rock surrounding and underlying it is dug away, the bone turned over, and the rest of the jacket applied to the other side. How many jackets, and how big a part is jacketed at one rime, will depend on the state of the skeleton. In an associated skeleton nearly every individual bone needs to be jacketed. If the skeleton is articulated and there is access to heavy lifting equipment, the whole skeleton can he jacketed in one go. The complete Colorado Stegosaurus mentioned above was airlifted from the sire by helicopter, but it is rare for such expensive resources to be put at the disposal of a dinosaur excavation.