NEWPORT NEWS, Va. - Jeff Johnston crouches low with his hammer and chisel, tapping patiently at what looks like dirty concrete surrounding a piece of rusted iron.

His hardened-steel tools resound, the sound rising up from the bottom of a deep, 20-foot-wide shaft that resembles a giant, mineral-encrusted water main.

For more than eight weeks now, Johnston and his fellow archaeologists have battled this stubborn material for hours at a time, laboring to unlock the secrets of one of history's most famous warships. Four hundred artifacts have emerged from its grasp so far, including a cache of officers' table silver as well as shoes, buttons, pocketknives and the remains of two long-dead sailors.

Less dramatic but equally important is the slow materialization of the walls, roof and other structural features of this celebrated Civil War milestone. Only now are their original surfaces beginning to appear after more than a century of marine encrustation and corrosion.

Four-man team

"The longer you stay in here and the longer you look around the more things you start to recognize," Johnston said, taking a break from his work at The Mariners' Museum.

"It's really starting to look like we're inside the gun turret of the USS Monitor."

Recovered from the Cape Hatteras, N.C., wreck in early August, the Monitor's revolutionary iron turret has been the focus of an intensive archaeological investigation led by scientists from the Monitor National Marine Sanctuary and the museum.

Made up of a four-man team of excavators and supported by what sometimes seems like a small army of sediment screeners, conservators and other helpers the archaeologists have removed tons of coal, coral and silt from the turret since they started. But no one realized when the work began how difficult it would be to reach the bottom.

Working on their hands and knees into the night, the excavators extracted the last of the human remains in September. Then and now, they say, hammering through the rust and coal in search of artifacts has required both stamina and patience.

"We're running into lots and lots of coal all the way down to and then in between the roof rails," explained Johnston, a Civil War naval historian who has become one of the leading authorities on the construction of the pioneering ironclad vessel.

The last few inches

"The problem is that some of the worst spots are in the last few inches. That's where all the good stuff has been found and that's where the concretions really get tough."

After nearly 140 years at the bottom of the Atlantic, the thick iron walls of the turret are loaded with unstable chloride salts. So they must be flooded every few days in order to stave off the potentially catastrophic effects of a reaction with the atmosphere, which could cause the historic armor plates to expand and crumble.

That dire threat has reduced the number of days when the archaeologists can crawl down a steep ladder into the giant, 70,000-gallon conservation tank and even then they must work in a dripping mist produced by a specially rigged system of irrigation hoses.

With days of digging behind them, however, the scientists have cleared nearly half of the turret, which tumbled upside down and landed on its roof during the violent sinking. They've also found scores of artifacts that have shed light on the tragic last moments of the stricken vessel.

Among the most poignant objects recovered is an intact lantern that may have been used to light the interior of the turret on the night the Monitor went down.

Equally moving is the discovery of more than a dozen silver forks and spoons from the officer's mess, three of which can be linked by identifying marks to the unfortunate owners.

"Two of the pieces have initials that can only be tied to a single person. The third is a flat-out certainty because it actually has a name," said museum collections manager Jeanne Willoz-Egnor.

"The sad thing is that none of them made it."

Gunnery tools, too

In addition to finding these provocative personal effects, the excavators have uncovered numerous gunnery tools, including a shot ladle and rammer head that were used to load and fire the Monitor's powerful battery of Dahlgren cannon.

Both of massive, 15,750-pound barrels remain inside the turret, resting in the topsy-turvy positions where they landed when the doomed ship slammed into the bottom.

Still visible on top of the portside gun is part of a celebratory inscription that was engraved after the Monitor's momentous clash with the CSS Virginia, also known as the Merrimack, in the history-making first Battle of the Ironclads.

And it's that kind of fragile evidence the archaeologists hope to preserve by continuing to work with patience and persistence.

"One of our big jobs after we're done here is going to be getting these cannons out," said John Broadwater, chief scientist and manager of the Monitor sanctuary.

"They're well-cemented in here right down to the roof beams and we have to decide if we're going to remove these massive gun carriages at the same time. So it's all going to depend on what we can do with the least amount of trauma to the artifacts."

Mark St. John Erickson is a reporter for The Daily Press, a Tribune Publishing newspaper in Newport News, Va.