The Nasswango awakens slowly to a moist midsummer dawn. Frogs mumble vaguely as they settle down to wait out the day. Wood ducks, not yet up and doing, peep and chuckle softly among the pond lilies. Bass and carp roll fin-out in the cypress-stained water, swirling the pollen that dusts the dark surface. Warblers perch trembling in the undergrowth as hunger struggles with timidity. Only the great blue heron is bold, his hoarse squawks echoing as he cruises above the shallows he will stalk.

The visitor whose canoe is drifting with the sluggish tide might be a thousand miles or ten thousand years from the city where he slept, yet bustling Salisbury is but 16 miles away and Snow Hill just down the road.A stone lofted over the bordering woods would land in a soybean field soon to be harvested by thunderous machines with two-way radios and air-conditioned cabs.

Nassawango Creek, a 15-mile arm of the great Pocomoke River, has always been a refuge. The Indians, whose aboriginal wisdom we are growing to appreciate, held it holy. From colonial to modern times slaves, bond servants, outlaws and other fugitives including solitude-seekers have hid out in its brier-laced and cypress-shrouded tangle.

Now the fugitives are the wildlife and the lush plants that so long fed and sheltered runaways. Over them hangs the threat of the farmer, caught in a cruel cost cycle that forces him to drain and fill the swamp and drench the land with chemicals; and of the lumberman, who must be efficient or fail, and whose chainsaw in a single season could destroy this remmant of a biological community that once held sway from Delaware to Dismal Swamp.

We speak of historical and cultural and natural and esthetic values but our true measure of worth is dollas, and the fact is that the only reason Nassawango has lasted so long is that it did not until recently become worth destroying. It is off the beaten track, or rather the track goes around it, following the firm ground.

Vast damage was done early on, when bog iron was made at Nassawango Furnace of ore scraped from the creekbed and smelted with charcoal from the forest and fluxed with oyster shells from Chesapeake Bay. The early ironworkers cast cannonballs for the Continental Army and cannon for the War of 1812, but the metal was fouled by phosphorous and could not be used for steel. The men went away, the works went to ruin, and the Nassawango went back to the wild.

"Now, with land and lumber at a premium, what we are pleased to call civilization is closing in again, but all will not be lost.

There are landowners along the creek who hate to be called conservationists, much less preservationists, but who love the Nassawango. Some have joined hands, more or less gingerly, with The Nature Conservancy, which uses tact when it can and tough tactics when it must, to save 3,500 acres of the creek and its watershed. With land and money donations they are setting forever free as much of the creek as they can capture for the cypress and the otter, the bald eagle and the carpenter frog, the deer and the dwarf trillium, the pileated woodpecker and the laurel-leaved greenbrier, the raccoon and the crossvine, the water oak and the weasel and every other living thing.

"Nassawango is the last great wilderness in Maryland," said Steve Hamblin, a reformed lawyer who heads the project for the state chapter of the Conservancy from his cramped office at 35 Wisconsin Circle in Chevy Chase. c"How much of it we can save depends almost entirely on how much money we can raise. We have commitments from landowners involving donations of about 1,000 acres but that probably is all we'll ever get. The rest will have to be bought, and the fact is that we have title to only 154 acres so far."

Hamblin scrabbled among his piles of papers, searching for his notes about the fantastic stand of Atlantic white cedar he searched out with a forester, and the bald cypress, 15 feet around at breast height, and long list of birds Chandler Robbins saw in one four-hour visit, and the rare or endangered plants and animals, and all the other facts and figures he sweats over when he cannot be out tramping the bog.

"We hope to go to settlement this year on five parcels totaling about 1,500 acres, but it has to be all ready money," he said. "It will take us $600,000 to carry the project through, and we don't have half that yet. It's hard to get donations in times like these even when it's all tax-deductible, but we have found a lot of generous people and we can only hope we'll find enough more of them, and soon enough."