Against a backdrop of the Toronto skyline across the bay of Lake Ontario, the 1972 Mariposa Folk Festival opened last Friday for a fascinating three-day run, complete with Woodstock-vintage johns and thundershowers - and a few surprise appearances by "superstars."

With six mini-concerts or workshops going on simultaneously all day, it was damn frustrating trying to pick which to attend. People wandered from one tent to the next on Centre Island, trying to decide between Owen McBride's spirited Irish rebellion songs (he has appeared locally at the Ark); John Prine, an up-and-coming Kristofferson discovery; and a blues workshop.

Festival-goers found it even more frustrating to learn of Joni Mitchell's surprise appearance at one of the tents after she had left. The festival, though, wasn't planned around "big names."

Instead, it presented some of the best - though not famous - performers in traditional ballads, blues, bluegrass, Indian, African, Middle Eastern, and African folk dancing, and topical folk.

The festival-goers, who were nearly all in the 18 to 30 year-old range, were attracted in especially large numbers to mini-concerts by Taj Mahal, and David Bromberg. John Prine, who dedicated his Your Flag Decal Won't Get You Into Heaven Anymore to the ultra-right wing Rev. Carl McIntire, drawled out his lyrics to an ever-growing audience.

On Sunday, before the afternoon heat and overwhelming crowds came, folk fans gathered by the bay shore to watch sailboats and listen to Kentucky's Jean Ritchie host a religious music program.

For those who didn't mind sloshing through calf-deep mud from the Saturday rains - and few did - the crafts area displayed handmade candles, pewter, jewelry, weaving, and leather goods.

Later on Sunday afternoon, Bonnie Raitt ended her act by introducing an unscheduled performance by Jackson Browne, who sang a reminiscent "Sweet Little 16." But wait a minute! Wasn't that Joni Mitchell's face peering over the tent flap out at the audience? Yes, indeed, but she wouldn't perform.

Shortly after, screams of ecstasy came from another tent area and heavy applause betrayed the appearance of another superstar. Thousands of lovers of esoteric folk music turned slightly teeny-bopper, rushing to that stage to see...Neil Young!

Appropriately enough, he began with "There is a town in North Ontario" from Helpless, Helpless. Called back, of course, for an encore, Young provoked a communal "Ooooh!" from listeners when he broke into Heart of Gold.