Factual error: Jack calls Gwen, and when Rhys takes the phone and hangs up on him, Jack's cell phone, for the second time in the series, sounds an audible, impossible dial tone. (00:13:00)
Factual error: Owen resuscitates Tommy using a defibrillator. The heart monitor shows a flat line, indicating Tommy's heart is not beating. A defibrillator has no effect in this situation. This is a widespread error in many films and TV shows.
Factual error: Martha picks up a bone saw to start the autopsy on Owen. An autopsy should start with a Y incision from just below the arm pits to the sternum and then down the stomach to the pubic region - using a scalpel, not a bone saw.
Answer: Several times during the episode, most notably at the beginning when the old grave is discovered, Tosh holds a devise that looks a great deal like the Sonic Screwdriver that she uses to determine the age of the skeleton. However, a search of Google images shows that it is not the same thing.
OneHappyHusky