TORONTO (CP) - The 10th annual Mariposa Folk Festival neared its end Sunday night with a concert highlight by the scheduled appearance of Joni Mitchell, one of Canada's best-known composers and folk singers.

It was the sixth consecutive appearance at Mariposa for the 27-year-old native of Fort Macleod, Alta., whose composition Clouds (Both Sides Now) won a Grammy, the recording industry's highest award, in 1969.

Another six-year veteran in the closing concert was David Rea of Toronto, former accompanist to Gordon Lightfoot, the Allen-Ward Trio and Ian and Sylvia.

Making their debut at this year's festival on Toronto's Centre Island were James Taylor, a discovery of the Beatles; country singer Merle Travis, best known for his composition Sixteen Tons; Scottish singer Norman Kennedy; Alexandre Zelkin, French-born singer of international songs now living in Montreal; and Angus McKinnon and his Scots Canadians dance band.

Rounding out the final concert program was Sara Grey, an American singer who first played at Mariposa in 1968.

THOUSANDS ATTEND

Audiences ranged from between 5,000 to 10,000 nightly at the three-day festival, while several thousand also attended daytime workshop sessions, craft displays and a North American native people's arts festival.

Tickets for all activities were $12.50 with day and night-time prices of $2 and $4 respectively. It was the third year for the festival operated by the Toronto Guild of Canadian Folk Artists, a non-profit organization, was held on the island.

There were a few incidents of crashes during the Saturday night concert when a handful of persons swam across the narrow lagoon separating the festival site from the amusement park area of the island. Police said there were no arrests and the situation was kept "cool."

The star of the Saturday concert was unquestionably Louisiana's Doug Kershaw, versatile instrumentalist and singer of Acadian heritage, whose flamboyant dress and performance brought repeated standing ovations and cries of "more" from the audience.

LONG CONCERT

It was unfortunate, however, that Kershaw, whose showmanship and talent stood out, amount the best of Mariposa's performers, drew the curtain-closing spot in a concert that had already lasted, without intermission, for four hours before he came on stage.

The result was that while his playing and singing-particularly his guitar and fiddle renditions of his own composition Louisiana Man-had people on their feet clapping, cheering and dancing in the aisles, his time-consuming patter and exchanges with ferry and tugboat whistles were irritating to a seat-weary audience.

Rambling Jack Elliott, whose singing style served as a model for Bob Dylan, was also called back to do another number and appeared again when Kershaw invited him on stage during the concluding act.

Conspiracy, a three-member group from Ontario's Pert Country, outdistanced all other performers at the opening day of the festival in showmanship, enthusiasm and talent.

While there were not many challengers in the first two categories, talent, however, was an ever-present commodity.

In both its daytime presentation and its appearance at the evening concert, the Conspiracy group was given standing ovations.

The vocal and instrumental group, formed in the last year, was supported in his presentations by about 30 members of the group's "family."

The "family," all residents of Pert Country who live in semi-communal fashion on half-dozen farms near Stratford, are all involved in the operation of Stratford's Black Swan Coffee House

PASS OUT FOOD

At Mariposa, while the Conspiracy sang their own compositions, female members of the "family," in ankle-length styles ranging from Grecian to gypsy, went among the audience handing out fruit, vegetables, crackers, cheese and cookies brought from their farms.

"What we want to try and do is involve people," says one member of the Conspiracy. "Our music does it on one level. The way we present it reaches people on other levels, and by letting people share the food we have grown we can speak to them in yet another way."