Jane Mason, medalist in the women's Maryland Amateur golf championshop being place at Kenwood, was among the casualties on a sweltering day yesterday, being ousted by Bonnie Johnson, a physical education teacher from Bel Air, 1 up.

Others to gain the quarterfinals included defending champion Patricia Thompson of Cumberland; Cindy Davis of Belair; Sally Voss of Congressional; Kathy Thompson of Kenwood; Karen Jones, the current District champion from Argyle; Mary Ellen Fedor of Chartwell, and Carol Davies of Washingtonian.

Davies fought an uphill battle to beat home favorite Lisa Abood on the fifth extra, or 23rd, hole. Davies was four down after the 11th hole but she won the 12th with a par, the 13th with a birdie and the 14th and 15th holes with pars to square the match. Both women birdied the 16th and 17th and both parred the 18th.

On the first extra hole, Davies got a break when her drive, which went into the woods, hit a tree and bounced out onto the fairway. She halved the hole and the next three before getting a par to Abood's bogey on the fifth extra hole.

Mason and Johnson were even going to the 10th and the match seesawed until Johnson won the short 15th with a par. The two golfers halved in to give Johnson the match.

Voss had a slightly tougher time than she anticipated with clubmate Arlene English, a recent American University graduate.

Voss lost the first hole but was never down again after squaring the match on the second hole. Voss was 2 up at the turn and won the 10th and 11th with birdies. After that, she breezed home until she shut out English on the 16th.

The survivors will be tested today, having to play two rounds before Thursday's 18-hole final for the championship. Temperatures are expected to be near 100 degrees.