Historical clue formulations

• Focus of a concussion protocol — 2026-08-21
• With 28-Across, temple services? — 2026-08-05
• Lettuce unit — 2026-07-20
• Circle at the top of a stick figure — 2025-05-20
• See 1-Down — 2024-03-28
• "Don't worry your pretty little ___" — 2024-03-11
• Top part — 2024-02-27
• O, in hangman — 2024-02-25
• Noggin — 2023-11-27
• Part of a river that ironically doesn't contain the mouth — 2023-01-14
• Leader — 2022-07-26
• Unit of cauliflower — 2022-07-24
• Place to go on a ship — 2022-02-20
• Beer topper — 2021-12-30
• Chairperson, e.g. — 2021-06-21
• *Graveyard sight — 2021-06-02
• With 70-Across, call it a night, say — 2020-08-19
• Circle in the game hangman — 2020-07-28
• Good thing to keep above water — 2020-03-10
• Chief — 2020-01-26
• Keep it under your hat! — 2018-11-04
• Herd unit — 2017-11-15
• Source of a river — 2017-11-03
• Noggin — 2017-07-03
• Key word #2 — 2015-11-29
• Foam — 2015-10-18
• Foam on a beer — 2015-09-01
• Big part of an Easter Island sculpture — 2015-04-22
• With 23-Down, deli product — 2014-07-22
• Captain — 2013-10-20
• Noggin — 2013-03-11
• Focus of a phrenologist — 2013-02-12
• Top dog — 2012-02-08
• With 37-Down, complete — 2011-12-29
• With 37-Across, hair accessory ... or a literal hint to 19-, 27-, 47- and 56-Across — 2010-11-29
• President — 2010-08-09
• Apt attachment to the starts of 14-, 17-, 35- and 43-Across — 2009-12-16
• Fourth row — 2009-08-27
• Commander — 2008-05-25
• Foam — 2007-11-21
• John, at sea — 2007-06-06
• Ranch unit — 2004-12-31
• Lucille Ball, notably — 2004-12-30
• Noggin — 2004-11-22
• Beanball target — 2004-11-09
• With 40-Across, a firebrand — 2003-09-11
• Nincompoop — 2003-08-14
• Cattle rancher's unit — 2003-02-06
• Brain's site — 2003-02-04
• Cattle count — 2002-11-27