Perhaps the dirt circles were never really necessary, and an 18th century example of runaway military spending. Perhaps the cannons were once too feeble to reach the Severn River and protect Annapolis. Perhaps the diminutive size inspired a diminutive name.

At any rate, they named it Fort Nonsense, spent a bit of money on it during the War of 1812 and the Civil War, and then forgot about it completely.

As the decades passed, it was overgrown with trees and shrubs. By the 1970s it was surrounded by a naval research center whose officers were privy to a lot of classified information but never knew a fort was in the back yard.

And then Fort Nonsense, the last vestige of Annapolis Harbor fortifications, was rediscovered in 1976 by the editorial cartoonist for The Capital, an Annapolis newspaper.

It happened because cartoonist Eric Smith sketches old forts in his spare time (he has made 99 watercolor sketches of forts thus far). One night a member of his gourmet dining club told him there was a fort up at the David W. Taylor Naval Ship Research and Development Center labs.

Smith, a former Army intelligence officer, had his security clearance updated, and on May 3, 1976, he passed through two guard posts, stumbled through some bushes and fell flat on his face into a ditch.

"Even before I hit the bottom I was laughing," he said. "I was happy: A ditch means there's a wall, and a ditch and a wall means there's a fort."

Today scores of people passed through those two guard posts for a ceremony at forgotten Fort Nonsense to celebrate its naming to the National Register of Historic Places. It means that it is officially historical and will not be forgotten again. But except for such ceremonies, it's location inside classified military territory means that it will remain inaccessible to public scrutiny.

If they let you in, this is what you see: You go through a thick grove of holly trees on the brow of a hill, and quickly come to the broad ditch that forms the circumference of the fort.

Stepping down into the ditch, you face a hill of earth nearly 6 feet high in some parts and, climbing that, you stand on a circular platform that is the center of the fort.

Through the overgrowth of trees visitors can make out the Chesapeake Bay Bridge off to the left. If the trees were cut down, a view of the Chesapeake Bay would be spread before you; the city of Annapolis is below on the right.

Archeologists from the Maryland Historical Trust say the earthen embankments are 64.9 meters in circumference. But beyond that, they cannot tell you a great deal. In 1983, archeologists scoured the area for about three weeks, digging exploratory trenches 5 feet wide and 5 feet deep. They found: One 1824 dime; one 1900 Colt .38 caliber cartridge casing; some nails and wire of "recent vintage;" one late 19th century bottle and some window glass; one 19th century pipe mouthpiece; pieces of modern ceramic flower pots; one modern plastic toy soldier.

"It was a little discouraging," admitted Richard Hughes, the state director of archeology, who worked on the project.

"One of the most interesting things was the 1824 coin that was found. That would indicate that the coin was deposited sometime after 1824, but that's about all it indicates."

Researchers believe the fort was built during the Revolutionary War or the War of 1812, when the British again were threatening Annapolis.

Hughes said he believes the fort, first built as a semicircle facing the river, was expanded into a full circle during the Civil War when Union Gen. Benjamin Franklin Butler dispatched 200 Massachusetts troops to Fort Nonsense to defend rear approaches to nearby Fort Madison.

The name, however, remains the most delightful and mysterious puzzle.

"Nobody knows definitely how it got its name," Hughes said. "One of the tales is that it was built in 1812 and that, after it was built, they suddenly realized it was so far from the water that if you fired a cannon, it would barely -- if at all -- reach the water.

"Somehow I doubt that," he added. "I think its more likely that the fortification was built to guard the approach to Fort Madison. Its possible it got the name just because of its size."