His political ideas are from 'the Stone Age'. [=are from the distant past; are very out of date]
Their lawyer said that he would 'leave no stone unturned' in trying to find more evidence.
The researchers 'left no stone unturned' in their search for the original documents.
(..) Check the ID on the patch. Bruce Wayne. - Any news on the missing item? - Not yet. They better leave no stone unturned. We can't leave a string of pearls on the manifest as lost. (..)2012 The Dark Knight Rises