Vampires jaw

You obtain the jaw through a quest line for discovering the vampires. After giving the restoration tools to the Astrologer, he tells you about the vampires he encountered. You suspect someone and check them out. After finding the vampire, he tells you about how the vampires in the Astrologers memory were bad ones.And tells you that you can use the witchers eye to look at memory spots and watch past events unfold.

You will eventually get to the location for the jaw going south from the right side of the waterfall. You find and dig up the jaw and go to Clotho. She gives you memory powder and a recipe.