A month-long archaeological exploration of the wreck of the USS Monitor has ended with the recovery of some three dozen artifacts, but with new evidence that the historic Civil War ironclad itself probably will never be salvaged.

Floyd Childress, associate director for operations and enforcement of the National Oceanic and Atmospheric Administration, said yesterday new films of the wreck have shown it to be even more fragile than previously believed.

In addition, Capt. Bill Searle, formerly the U.S. Navy's chief salvage officer and a technical adviser on the Monitor project, viewed the wreck from a submarine last Saturday and pronounced it "a heap of rubble."

Searle, skeptical since the Monitor's wreck was first located off Cape Hatteras six years ago that the vessel would ever be brought up intact, estimated in April that if such a project were possible it would cost some $10 million.

"But after seeing it, I would not sanction spending one nickel on bringing it up," Searle said yesterday. "There are numerous holes in the deck . . . you can see daylight coming through . . . I've seen a lot of old ships but this one looks like Swiss cheese."

The Monitor, which made naval history when it battled the Confederate ironclad Virginia (formerly the Merrimack) to a standstill in Hampton Roads on March 9, 1862, foundered in a gale off the Carolina Outer Banks on Dec. 31, 1862.

The exact location of the wreck, however, remained a mystery until 1973 when a Duke University expedition found the vessel in 210 feet of water about 16 miles southeast of Cape Hattaras.

The discovery touched off numerous proposals for raising the vessel -- schemes ranging from filling her with Ping-Pong balls to lifting her with the spy ship Glomar Explorer.

Most of those most involved with the Monitor since her discovery, however, have recommended a cautious approach to any salvage efforts, arguing that considerable basic archaeological and engineering information about the wreck would be required before such project could be considered.

The federal government made the Monitor wreck the first U.S. marine sanctuary in 1975 and controls all rights to scientific research on it.

The 28-day expedition, which wound up Sunday, was a joint effort of NOAA, the state of North Carolina and the Harbor Branch Foundation of Ft. Pierce, Fla., an underwater research and development center underwritten in part by the Johnson and Johnson pharmaceutical fortune.

Childress, de facto director of the expedition said yesterday the operation had proved "very successful."

In addition to making the first complete underwater survey of the wreck, he said, scientists and technicians logged 49 dives and 35 man hours on the wreck in an ocean environment among the least hospitable on earth.

The expedition, he said, lost only three days due to bad weather, and Saturday returned with unprecedented films obtained in "more than exceptional" underwater visibility of greater than 100 feet.

Artifacts recovered ranged from a 7-foot crane that launched the Monitor's whaleboat to a porcelain soap dish -- probably from the captain's night stand -- and a 3-inch-diameter embellished brass base from a whale-oil lamp in the wardroom.

Childress said the expedition also completed the archaeological excavation of a roughly 6-square-foot area of the captain's cabin and obtained numerous wood samples that further confirmed the fragile nature of the wreck.

The samples, he said, show "extensive" damage to the vessel's structural timbers from terredos, or shipworms, during the 117 years the Monitor has lain beneath the sea.

While some proposals still are being discussed for raising the ironclad's characteristic turret -- apparently in excellent condition -- the aesthetic and scientific value of leaving the vessel where it is, Childress said, may far outweigh any obtained from disturbing it.

The Monitor looms in the other-wordly light of 35 fathoms like some water-logged ghost ship, her turret askew beneath the overturned hull.

White clusters of occulina coral festoon her armor and lacy pink and white fanworms wave on her bow.

Amberjack, black drum and sea bass ply lazily through the wreckage and a 4 1/2-foot-long, 100-pound grouper panhandles for food like an overweight vagrant.

Frozen in time lie the actions of another century -- dents from the Merrimack's shells mark the turret, and the anchor chain lies played out in what was the ship's last futile effort to save herself.

Through the disarranged hull plates the wheels and boilers of the engine room lie crusted with plant life, now the domain of whiskered toadfish and small moray eels.

Future archaeological exploration of the wreck, Childress said, might provide useful data for constructing a replica of the historic little ship, whose flush decks, rotating turret and screw propellor inspired a century of warships after the age of sail.

But other than that, he said, it may be better to leave the vessel itself to time and the sea.