When evolutional archeologoists go out into the field, they are looking for items to veryify their theories and will discard all other items that don't fit their theories. If I had a preconceived notion that man came from birds, for example, then I could go into a cave and see a line on the wall and claim that the beak of a bird formed that line. Then if I found feathers on the ground, I could go into my lab and test the age of the feathers. If they were found to be very old, I could claim that the bird dropped those feathers as it was forming into a man. And if I had a Ph.d. and enough money to do more research, I would get believe to believe me. It really isn't very hard to do. You have to remember that the theory of evolution wasn't accepted in the scientific community until 50 years after it was postulated. But with enough time and zeal, scientists can convince the public of anything.