What was going on when I was born?

LONG ISLAND SOUND, a body of water that has received little detailed study, will be monitored to identify sources of pollution under a Federal program to begin this fall. Though at $1 million the dollar amount for the program is small, it may lead to preventive actions that can tap Federal money that is available for cleaning up coastal sounds and bays. The monitoring program will be administered by the United States Environmental Protection Agency. ''Given the enormous economic benefits and the quality of life the Sound gives us, it behooves us to make a modest investment to protect the water,'' said Senator Alfonse M. D'Amato, a sponsor of the legislation that established the program. ''It is far more difficult to rectify damage than to avoid it.''

The colonel and the peasant stared into the dark, listening to the murmur of soldiers settling into bivouac. A soldier had toppled a hen from a tree branch with a slingshot, and the officer and farmer were waiting for their chicken dinner. The colonel asked if people in Joateca, a town in the northern province of Morazan, supported the left. ''Yes,'' the old man replied. ''Many?'' the colonel inquired.

It's been a long while since Hollywood abandoned its traditional model for relations between the sexes: the boy-meets-girl, boy-loses-girl, boy-gets-girl romance, followed by a middle-aged period devoted, happily or otherwise, to intense domesticity. It's even been a while since, in the early 70's, changing perceptions of men's and women's societal roles left Hollywood increasingly unable to deal with romantic relationships at all. Hollywood's bewilderment in a period of vigorous social change brought about movies in which the lovers never quite fell in love, or the kinds of working-woman stories in which Jane Fonda (as she did in ''The China Syndrome'') came home alone to a pet turtle and an answering machine. The silence on the subject of sexual relations has been prolonged and uneasy. But it now appears to be drawing to a close.

Seeking to solidify support behind his underdog candidacy, Walter F. Mondale today conferred with 15 Democratic governors and set a meeting for Tuesday with the Rev. Jesse Jackson and other black leaders. Political associates of Mr. Jackson said the civil rights leader, who attracted record numbers of black voters to the polls in the primaries, appeared to have settled his differences with Mr. Mondale. They said they expected him to announce that he would campaign extensively for the Democratic ticket in the fall. Complaints of Insulation Mr. Mondale's meeting with 15 of the nation's 35 Democratic governors today followed complaints that his campaign staff insulated him and that he was closed off from the advice of other Democrats.

While the Hamptons on Long Island's South Fork have long been known as chic summer retreats, vacationers are becoming more familiar with the pleasures of the villages along the North Fork on Long Island Sound. To meet what it sees as a growing demand for vacation housing there, a development group is building Stirling Cove, a 48-unit condominium colony on a 5-acre site on Stirling Harbor in Greenport.

Spurred by the growth in the American economy and the recession in Europe, an Irish development company has entered the real-estate market in this country with a $10 million condominium project in Westchester County. The Durkan Bros.

GLASSBORO HEADS bowed, eyes downcast, they walked slowly in the baking sun. From time to time, one would cry out in an archaic tongue, and others would come to look and marvel. Pilgrims? Penitents? Players in a medieval pageant? Adherents of some arcane sect? No to the first three. Not quite no to the fourth.

WITH A DAUGHTER'S EYE A Memoir of Margaret Mead and Gregory Bateson. By Mary Catherine Bateson. Illustrated. 242 pp. New York: William Morrow & Company. $15.95. MARGARET MEAD By Jane Howard. Illustrated. 527 pp. New York: Simon & Schuster. $19.95. TWO completely different biographies of the same person, opposed in their vantage points and yet complementary - the one, by Catherine Bateson, is intimate and personal; the other, Jane Howard's, is public and archival. Together they would make a complete account, a whole life of Margaret Mead, were it not that the eminent anthropologist seems destined to escape even those who knew or studied her best. This includes Miss Bateson, Mead's daughter, who explains why.

In the first 127 days of the season, through Aug. 6, the Mets either were in first place or were within two games of first for all but 16 days. In the 19 days since Aug. 6, though, they have been more than two games out 18 days. In other words, the Mets have picked the worst time of the season to have their worst time of the season. They have had help, of course. From Bob Brenly, for example. Brenly, who destroyed the Mets with two home runs in the first game of Friday night's doubleheader, swatted a three-run homer last night that plunged the Mets to a 5-4 loss to the San Francisco Giants.

Any lingering concerns that the current expansion is not cooling down should be dispelled this Wednesday when the Index of Leading Economic Indicators for July shows a drop for the second month in a row. ''Not only do we expect the Government to report that the index will be down as much as 1 percentage point, compared with the nine-tenths of 1 percent decline in June, but we don't think the June figure will be revised,'' said Irwin L. Kellner, chief economist at the Manufacturers Hanover Trust Company. Because the May indicator was revised to a plus four-tenths of 1 percent after initially being reported to be down one- tenth of 1 percent, many economists have assumed that June's minus nine- tenths of 1 percent would also be changed to show a smaller decline. ''The fact is we are in a cooling period, which is normal and healthy for the third year of a recovery,'' Mr. Kellner said. ''This trend will be supported by gross national product in the third quarter, which should show a gain of about 4 percent, compared with the 7.6 percent rise for the April-to-June quarter,'' Mr. Kellner said.

Toasts were once drunk from them to honor reigning ballerinas. Ground glass poured into them could put a rival at least temporarily out of commission. They helped to define the spirit of Romanticism in the ballet. They are often the object of almost fetishistic attention. And classical ballet seems faintly cloddish today unless there are toe shoes somewhere evident on stage. Glistening satin, with a firm, boxed toe and flimsy drawstring heel with lacing ribbons and elastic, the toe shoe gives the dancer's leg a tapering line no human limb would otherwise have. The shoe emphasizes the lyrical curve of her foot. It is a curve developed, if the dancer is lucky, through years of training that wearies the legs and soul but produces feet like steel that can turn and hop and travel across the stage on the tips of the toes.

After more than two hours of swimming, biking and running through and around Manhattan yesterday, Mark Allen of San Diego, and Scott Molina of Del Mar, Calif., who was making his first visit to the city, decided to have a chat. The two were near the finish line of the first New York Triathlon, a grueling three-stage race that included a 1.9-mile swim in upper New York Bay, a 21.3-mile bicycle excursion on the West Side Highway and the Henry Hudson Parkway and a 7.4-mile run through a picturesque Central Park on a bright and breezy morning. They were running side-by-side. ''We both just kind of looked at each other and said, 'Well, who's going to take off first?' '' Allen would later say. ''He's so much faster than I am that I knew I had to try and build a lead.'' The 26-year-old Allen did just that, bursting out to a 20-yard margin before crossing the finish at the Tavern on the Green restaurant in 2 hours and 5 minutes, 5 seconds ahead of Molina.