Steve Jones, despite a heart defect that left him weary in the high altitude, led qualifiers into the third round of the $1 million International tournament yesterday in Castle Rock, Colo.

Jones, taking medication for a heart condition and playing at 6,300 feet, had a 67 medal score, including an eagle-3, and 13 points.

Jack Nicklaus and Greg Norman each fell victim to what Nicklaus called "stupid mistakes" and were among 24 players eliminated.

Nicklaus, 47, holder of a record 18 major professional titles, said he got caught up in the unusual format and scoring system used in this tournament. "Under this format, a birdie and a bogey is better than two pars. I was trying to play to that format and it cost me two double bogeys," he said. " . . . It's nobody's fault but mine."

Nicklaus finished with minus-4 points under the modified Stableford scoring system: An eagle is worth five points, a birdie two, par zero, bogey minus-1 and double bogey or higher minus-3. Nicklaus had a medal score of 77.

Norman finished with a medal score of 78, 6 over par, and a minus-5 point total.

Tom Watson and Ben Crenshaw also qualified for the third round.

LPGA: Valerie Skinner eagled the 17th hole and finished with a birdie to cap a round of 5-under-par 67 and take the first-round lead in the $225,000 International in White Plains, N.Y. Skinner, 27, drove 235 yards on the par-5, 465-yard 17th, then hit a one-iron approach shot 210 yards, 25 feet from the cup.