SHELTER ISLAND, N.Y. -- Alice Fiske, grande dame of Sylvester Manor on this coastal island, emerged from the stately Georgian house, steadying herself with a walking stick, to inspect the defacement of her handsome front lawn. She couldn't have been more pleased about the big hole there, the mark of archaeologists at work.

"You know, we have so much history here," Fiske said, nodding toward the dig, then the house and the water beyond, where ships of commerce once tied up and a society of cultural diversity took some of its first steps in the New World.

Archaeologists are not only digging into the past of her late husband's family, going back to the middle of the 17th century, but are also discovering material remains of an aspect of American Colonial history little known and rarely investigated: the existence of Northern plantations worked by African slaves.

"People generally assume all the plantations with slaves were in the South," said Stephen Mrozowski, an archaeologist at the University of Massachusetts at Boston and co-leader of the excavation. "No one has really looked at the archaeology of a Northern plantation in a systematic way."

As the second summer of excavations drew to a close, Mrozowski said the new findings, combined with a study of old wills, deeds and other documents, were beginning to reveal patterns of life and work on the Sylvester plantation, which at one time encompassed virtually all of Shelter Island.

'Provisioning plantations'

Starting around 1650, this was a major enterprise with a long economic reach. Unlike Southern plantations, which concentrated on large cash crops like tobacco and cotton, this was one of several "provisioning plantations" founded at the time in the North. Its main function was to supply food and timber for the Sylvester family's sugar plantation on Barbados in the West Indies. Ships regularly sailed to Barbados bearing cured meat, grain, barrel staves and lumber and returned with molasses for making rum.

"We're seeing the beginning of the modern world," Mrozowski observed. "These people were already thinking of commerce on a global scale: labor from Africa, a plantation in one place supporting another far away and the products being traded on two continents. And you see all these cultures coming together, English, Dutch, Native American and African."

At both plantations, much of the labor fell to African slaves. According to inventories in the 1680s, more than 20 slaves worked at Sylvester Manor, more than 200 on Barbados. The slaves are listed on lines just above the inventory for livestock.

Only a generation or so after the settlement of Jamestown in Virginia, in 1607, and the arrival of the Pilgrims at Plymouth, Mass., in 1620, plantation culture had spread to a few places on the Northeast coast, where Africans were brought in as slave workers. Excavations here, the archaeologist said, could reveal whether there were differences in the lives of Africans on Northern plantations compared with those in the South, perhaps reflecting differences between a provisioning plantation and those based on large crops requiring intensive field work.

Mark P. Leone, an anthropologist at the University of Maryland College Park, said the excavations should turn up "interesting and important results" about the role of Africans in early American culture, particularly in the North.

Neglected

Until about two decades ago, African-Americans were a neglected element in archaeology. Excavations at plantations usually focused on the architecture of the big houses of the white masters and were confined to the South. As an example of the changing emphasis, Leone has been investigating the slave quarters of historic houses in Annapolis, Md., to learn how the slaves maintained their African identity.

The excavations at Sylvester Manor are directed by Mrozowski and Marley Brown, director of archaeology at Colonial Williamsburg in Virginia. The two had worked together on a dig at Jamestown, the first permanent English settlement in what is now the United States. A third partner is the Shelter Island Historical Society.

Stepping down into the excavation on the front lawn, Mrozowski said, "The beauty of archaeology here is, we only have to go down inches to get to the 17th century."

Here the archaeologists were looking for traces of the original plantation house, built in 1651; the present manor house dates to 1735. They found some Dutch-made yellow bricks and red roof tiles that belonged to the old house.

"We know the present house was always painted yellow, probably because the original one was built of yellow brick," Fiske said.

So far, the foundations of the original house have eluded archaeologists, perhaps because it stood on the site of the present house. But they think they may be able to learn even more about plantation life from the artifacts coming out of the lawn and other dig sites. Where he stood, Mrozowski said, he and his graduate students uncovered a deposit of 17th-century trash. This must have been outside the kitchen, most likely a free-standing structure in those days and a place occupied by the slaves.

Slave house?

Indeed, excavation also exposed the wood stains from decayed posts, coral-based mortar and other traces of a building. Mrozowski said he was not sure, but the arrangement of the post holes and trenches reminded him of construction patterns of some slave houses made of clay or mud mixed with branches or straw -- wattle and daub -- on South Carolina plantations. These the slaves had built themselves along the lines of dwellings where they or their ancestors had come from in West Africa.

Among animal bones, remains of plantation meals, archaeologists here found broken pottery they considered even more distinctive evidence of an African presence. The pieces, gray to brown and unglazed, were from earthenware cooking pots in a style known to archaeologists as colono ware. For a long time, such artifacts were thought to be Indian pottery. Now, archaeologists have noted similarities to pottery in Nigeria and Ghana and agree that Africans, not Indians, were its primary if not exclusive makers in the New World.

Some Indian artifacts, primarily wampum shells, have been uncovered on a peninsula near the manor house, but it is not clear what role Indians had in plantation life. The shells could be from a pre-plantation encampment. But Indians lived on the island after the Europeans' arrival. The island's first census, in 1771, counted "140 persons white, 27 slaves, five free negroes, 23 Indians."

Nathaniel Sylvester, founder of the plantation, emigrated from England to the New World, probably by way of Holland, and, with some partners, acquired the land from the Montauk Indians. (Fiske's husband, Andrew Fiske, was a descendant of the Sylvesters.)

Cosmopolitan family

From the evidence in the trash deposit -- or midden, in archaeological parlance -- the Sylvesters were a cosmopolitan family and their plantation prospered from the start. "It's the most upscale midden I've ever excavated," Mrozowski said.

Two student archaeologists, Ann Hancock and Lee Priddy, arranged a sampling of their artifact haul on a table inside the manor house. There were English, French and Irish coins; fine German ceramics along with humbler colono ware; silver buckles and a stick pin, and pieces of Dutch clay pipes and a copper pipe tamper.

Behind the manor house, on a lawn sloping to Gardiner's Creek, the archaeologists have uncovered traces of 17th-century outbuildings that appear to run down to the water. They suspect that these were places where workers made the barrel staves and stored the goods to be transported on the next ship to Barbados. Further excavations are planned here.

Of all the artifacts, the one most prized by Fiske is a rusted latch key, 4 inches long. Because it was found in the 17th-century midden, archaeologists told her it was most likely the key to the original manor house, and one more key to the past of a Northern slave plantation.