About Revisions Isseki Misaki Yonnaguni Town, Okinawa 907-1801, Japan More Info Max Depth: 91-100ft/28-30m Average Viz: 111-120ft/34-37m Entry Type: Boat Bottom Composition: Rock Aquatic Life: Big Animals Spring: 71-75°F/22-24°C Summer: 81-85°F/27-29°C Fall: 76-80°F/24-27°C Winter: 66-70°F/19-21°C 2/01/2013 10:50 PM

http://en.wikipedia.org/wiki/Yonaguni_Monument

The Monument consists of medium to very fine sandstones and mudstones of the Lower Miocene Yaeyama Group believed to have been deposited about 20 million years ago.[1] Most of the formations are connected to the underlying rock mass (as opposed to being assembled out of freestanding rocks).






The formation called "The Turtle"


The main feature (the "Monument" proper) is a rectangular formation
measuring about 150 by 40 m (490 by 130 ft) and about 27 m (90 ft) tall;
the top is about 5 m (16 ft) below sea level.[5]

Some of its details are said to be:

• two closely spaced pillars which rise to within eight feet of the surface;
• a 5 m (16 ft) wide ledge that encircles the base of the formation on three sides;
• a stone column about 7 m (23 ft) tall;
• a straight wall 10 m (33 ft) long;
• an isolated boulder resting on a low platform;
• a low star-shaped platform;
• a triangular depression with two large holes at its edge;
• an L-shaped rock.