days marked with a white stone

"...whiteness has been even made significant of gladness, for among the Romans a white stone marked a joyful day..." Moby-Dick (1851)

Oct. 7.—Mark this day with a white stone! After travelling sixty or seventy miles off the road—encamping each night on the river in comparatively good grass, and with driftwood fuel too, I this morning, as guide, took a course for the crossing of the Pawnee Fork, and struck it to a degree! ....This has been a true October day—delightful and magnificent October!

 Scenes Beyond the Western Border, January 1852

Scenes and Adventures in the Army

"... you desire to hear of Colonel John Moredock. Well, a day in my boyhood is marked with a white stone—the day I saw the colonel's rifle, powder-horn attached, hanging in a cabin on the West bank of the Wabash river."  The Confidence-Man (1857)