General View of Blue Hole, Castalia, Ohio (Note: In 1895 Castalia had a population of 427.)

Discovered by Robert Rogers, 1760, the most extraordinary Spring in existence. Unknown
depth, visible depth 45 feet, and 75 feet in diameter, Source of water underground river.
Temperature 48 degrees, winter and summer. It never freezes and is not affected by floods
or drouth. Discharges 5,000 gallons of water every minute. Fich cannot live in Blue Hole,
as it is absolutley free from air or food. The water is blue in color and extremely clear
and supplies water for a brook trout fishing club.