Grants or patents conveying control of underwater lands are not unusual.

Now that it owns underwater land, the conservancy will be able to carry out its own experiments and programs.

The zoning changes would forbid using underwater land when figuring the permissible size of a building.

The Outer Continental Shelf is underwater land more than three miles off the shore of any state.

Other grants that included underwater land were made to individuals for commercial endeavors, including the building of wharves.

When some Sea Gate homeowners failed to pay taxes on the underwater land behind their homes, the city took over the rights.

"I don't believe that the city's Zoning Resolution has to recognize development rights being generated by underwater land," he said.

The boundaries of underwater lands are often vague.

And never go near Tir-na-n-Og, an underwater land that is the favorite fairy dwelling.

Such a move, Mr. Zalben said, would be allowing the use of public underwater land for individual use.