Excavating a fossil is a slow, careful process. When we come across a layer with fossils, it is unlikely that it is the current surface of the ground. So, some degree of removal of the sediment above the fossil layer, called “overburden” must be done. Depending on the specifics of the location, this might involve picks, shovels, chisels, jackhammers, or backhoes.
Once the area immediately above the fossil is exposed, we dig downward onto the fossil layer. The term “digging” here really should be “scraping,” when you are close to fossilized bones, we use blades and dental picks, not shovels and rock hammers, to prevent destroying the very specimens we want to collect.
As bones are exposed, they need to be protected. Fossilized bone may be dense, but it is often fragile and subject to shattering. Often a protective consolidant is painted or dripped onto the specimen. The mixture penetrates the fossil and enters microscopic cracks, this helps to hold the specimen together and makes it more resilient.
Smaller bones and teeth might be wrapped up with paper towels and aluminum foil, requiring no added protection. These can be carried back to the field vehicle as is. But larger bones or sets of bones still in articulation require more protection. A very standard technique in field paleontology is “jacketing”. The upper surface of the bone is exposed, the field worker then moves downwards until the bone is on top of a short pillar of sediment. Then layers of plaster and burlap is laid over this. The team then undercuts the pillar, tips the pillar over and hopes that the whole block doesn’t fall apart in the attempt.
Quarry sites are mapped as the bone layer is exposed. This information is important to help reconstruct the taphonomic setting of the layer, which will help in reconstructing what happened to the bones between the death of the animal(s) and their burial. If nothing else, it is important to figure out which bones go with which individuals!
Each fossil specimen can be important, it has the potential to add to scientific knowledge about life on Earth. The information associated with the specimen is as important as the actual fossil, and fossil collection often is as much about collecting data as it is about collecting specimens.
For most of my life, I have been exploring the earth below my feet, searching for remnants of life that existed on this planet millions of years ago. I have recovered thousands of fossils from the ground, yet I have never lost the excitement to be the first person to find and touch one of these ancient creatures.