IT IS NOON in Harvard Yard, and for the most part, the drilling has stopped. Construction crews, breakage from their work on the Yard's water main, lounge in the shade of tall elm trees to eat their lunch.

Inside the deep trench by Harvard Hall, wearing a yellow hard hat, John N. Stubbs '80 is still busily filling shallow cardboard boxes with trash--mostly small white tubes and shards of broken glass and pottery. One box is nearly fled with large chunks of broken glass, the remains of wine bottles.

The bottles, he says, were probably discarded by undergraduates in the eighteenth century. "The yard was by no means dry at this time." Stubbs notes.

"it's definitely other peoples' garbage we're going through here," says Stubbs, a Harvard archaeologist who recently received is Ph.D. Here.

Since construction began in early summer, Stubbs has worked at the water main site. Every day workers big through the Yard, Stubbs is there, monitoring the work and scouring the soil for clues to Harvard's past.

This portion of the Yard--"the backyard of the College"--is rich with artifacts, now-valuable trash, from as far back as the 1690s, Stubbs says.

In the earliest days of Harvard, New England citizens generally dumped debris just outside their back doors, he says. "The backyard tended to be where people threw away their junk. They literally tossed it away."

From within the gaping hole, it is easy to pick out the layers of dirt. One strip has never been disturbed, even by later utilities work in the Yard. Most of the riches in that level of dark soil date back form about 1700 to about 1760, he says. Stubbs has found saucers and pottery, as well as animal bones--the remains of students' food.

The thin white tubes that nearly fill one cardboard box are pieces of tobacco pipes, Stubbs says. Mostly English in origin they were used between 1640 and 1760. Archaeologists can date the artifacts according to the hollow pipes, because over time, they were made with smaller and smaller holes.

"it's like somebody dumped their ashtray," he says.

In addition, Stubbs says he found "an extraordinary number of wine bottles." most made of green hand-blown glass.

In two days, Stubbs says, he uncovered more bottles than he had in four years of excavation in the center of the Yard. The number of bottles in the Yard, he says, exceeds what archaeologists find at typical tavern sites.

Because Stubbs has found no kitchen utensils in this trench, he believes the wine was consumed by students who lived in Harvard's old buildings.

"I will assume, and I think fairly safely that a lot of this was probably student-generated," he says.

Harvard records, Stubbs says, show that drunken behavior was frowned upon, and transgressing students were penalized financially.