Historical clue formulations

• Make even deeper — 2010-06-16
• Excavate again — 2007-02-26
• Make even deeper — 2006-11-22
• Fix, as a trench — 2006-09-07
• Make even deeper — 2005-12-28
• Make a new excavation — 2005-03-13
• Make a new hole — 1999-10-23
• Do further archeological work — 1999-01-24
• Use the spade again — 1997-10-12