BERMUDA is a house of sand. Standing some 16,000 feet, or three miles, off the seabed in the area of the North Atlantic known as the Bermuda Rise, the island is nothing more than a large sand dune perched on the summit of a long-extinct oceanic volcano.

So while we continue to build up our sandcastle of 393 years ? independent or otherwise ? some reflection on our origin and its connection to Bermuda's outstanding heritage in stone might be in order.

The formation of Bermuda began over 100 million years ago, when a hot spot in the mantle of the Earth began to erupt under the sea.

Slowly and solidly, the basalts and other volcanic rocks built up a mountain that one day broke through the surface of the sea. Like Hawaii or Montserrat, it became one of nature's great fireworks displays, probably ending the light show some 5,000 feet above the sea.

That is a far cry from the present highest point on the island at Town Hill, Smith's Parish, which at 258 feet is some 200 feet shorter that Khufu's Great Pyramid at Giza.

The sea eroded the volcano, the waves working a destructive wonder until Mount Bermuda sank below the swells, leaving a shelf some 32 miles in diameter, with two smaller plateaus at Argus and Challenger Banks. Coral began to grow on the undersea mountaintop and the world's northernmost atoll took shape.

Then about a million years ago the Ice Ages came into being, locking up much of the water on the planet, and sea levels dropped up to 600 feet.

The atoll was exposed and its reefs ground into sand by the sea. Winds drove the sand into dunes and Bermuda as we know it was founded.

Some of the dunes were eventually turned into rock by the corrosive action of rain, which combines with carbon dioxide in the air to make a weak carbonic acid.

Since the sand is derived from seashells, it is a type of calcium carbonate and is dissolved by the acid. The liquid thus produced solidifies upon drying and Bermuda limestone is created.

The older the stone formation, the harder it becomes, as more liquid seeps into its pores. Thus, one day we will have to paint the limestone of the dockyard ramparts, as the same geological forces that made the stone is dissolving it today.

This process can be seen at the entrance of the Bermuda Maritime Museum, where the liquid is making stalactites on the ceiling of the gateway, stalagmites on the road and flowstone down the wall surfaces.

The making of lime for cement and the working of limestone for building is a tradition several thousand years old and the first settlers on Bermuda in the early 1600s would have been aware of such methods.

In Bermuda, through the accident of geology, the original Bermudians had all the ingredients necessary to make stone buildings and there was also cedar aplenty for roofs and other purposes. The first stone building on the island was Paget Fort, erected for the defence of St. George's in 1612.

The essential building ingredient was lime, which was produced by burning stone that had a high content of calcium carbonate.

For this the older and very hard Bermuda limestone, such as found at Dockyard, was needed. The lime rock was layered with wood in a lime kiln, which burnt for some days, the stone reducing to powder or lime.

The last burning of a kiln was in 1990 at Ferry Reach by the late Orville Bascome of St. George's.

On nearby Coney Island is the finest lime kiln in Bermuda, which was built by the Royal Engineers in the mid-1800s. Recently my friend and lime expert, Ken Uracius, looked at this monument to industry and tradition and declared: "It's a continuous burn." Unlike the civilian kilns, this one was designed to burn rock around the clock and was lined with brick to cope with the intense heat generated by the process.

A ramped roadway accesses the top of the kiln, so that new rock and timber could be added to the combustion. The lime was raked out of a small doorway at the bottom of the kiln. Another military kiln exists at Ferry Reach Park, somewhat infested with Mexican peppers. Paul and Penne Leseur discovered a new civilian kiln was at Hog Bay Park after Hurricane Fabian swept away vegetation.

Britain, the process of making lime was industrialised and most of the individual kilns have been lost. The Bermudian kilns are small monuments to an ancient building method and an essential part of the traditions of the island that produced our outstanding domestic architecture.

Being of the same material, the mortars of lime mixed with local sand were completely sympathetic to Bermuda stone. The lime also provided the paint for Bermuda roofs and many of us remember the barrel of lime and water in the back yard, awaiting a little stirring and the application of paintbrushes.

Modern Portland cement is not sympathetic to Bermuda stone, for it is too hard and does not breathe. The restoration of old Bermuda buildings should be undertaken with lime mortars, sadly not now generally used.

Lest we completely forget what our forebears and some still alive remember, Ken and I have it in mind to restore the kiln at Coney Island and have a continuous burn once again, transforming rock around the clock. The lime produced could be used in the restoration of the fortifications for which it was built in the first place.