Simplify the following text for a Grade 6 native English-speaking person.
Original: This research identifies this not only with Stillbay sites that date back to 72,000 BP but sites that could be as old as 164,000 BP .
Simplified: This clue shows this not only with Stillbay sites that date back to 72,000 BP but sites that could be as old as 164,000 BP .