If we were to conservatively say that a generation passed once every 25 years (and when was the last time a generation was 25 years long?), then in 100,000 years a total of 4,000 generations would occur. If the number of people on earth never exceeded 1,000,000 at any one time in the past, then in 100,000 years a total of 4,000,000,000 people would have lived, died and been buried somewhere on earth. This is an astronomical number.
The amount of remnents in the ground should be everywhere.