Front:
1BLUE HOLE
Back:
ENTRANCE TO BLUE HOLE
CASTALIA, OHIO
Six miles west of Sandusky, Ohio, on Route
269. The depth of the Blue Hole is unknown.
The visible depth is apparently 50 or 60 feet.
It finds its source in an underground river and
maintains a temperature of 48 degrees, winter
and summer. It is not affected by floods or
drought. The volume of water flowing from
this marvelous spring is seven million gal-
lons daily, sufficient to supply a city of 75,000
population.
DISTRIBUTED BY RICH-HOLT CO., SANDUSKY, OHIO
7C-K1475
CURTEICHCOLORⓇ 3-D NATURAL COLOR REPRODUCTION (REG. U. S. A. PAT. OFF.)
HERE
