Historical clue formulations

• Ridge formed by glacial streams — 2020-04-16
• Glacial ridge — 2013-05-22
• Gravelly ridge — 2013-04-21
• Glacial formation — 2012-04-29
• Glacial ridge — 2006-07-12
• Glacial ridge — 2003-05-20
• Gravelly glacial ridge — 2002-07-14
• Gravelly ridge — 2002-04-27
• Glacial ridge — 2000-12-06
• Geological ridge — 2000-05-14
• Gravelly ridge — 1999-10-23
• Geological ridge — 1999-05-13
• Gravelly glacial ridge — 1994-11-23
• Glacial ridge — 1993-11-28