Historical clue formulations

• Southwestern gully — 2025-01-08
• Arid region's watercourse — 2010-09-30
• Wash — 2009-10-03
• Steep-sided gulch — 2007-01-25
• Southwestern gully — 2005-06-15
• Dry gulch — 2001-12-26
• Dry creek — 2000-06-08
• Gulch — 1999-02-04
• Gulch — 1995-02-01