For fossils to thrive, certain favorable circumstances are required. First of all, of course, remnants of life have to be there. These then need to be washed over with water as soon as possible, so that the bones are covered with a layer of sediment.
I worked on 'Sarah Connor' even longer than 'Firefly.' And I always remembered how generous everyone was to me when I didn't know what to do, and I didn't know the rules, and I didn't know camera angles, and I didn't know lighting.