The number of undefeated Ivy League teams was cut to three last Saturday, and the stage was set for what may be the pivotal game for the League championship.

Harvard, by shutting out previously undefeated Cornell, 21-0, elevated itself to the position as Dartmouth's number-one threat. Dartmouth repeated its big offensive show of the Princeton game by crushing Brown, 49-14. Saturday, Harvard and Dartmouth clash.

Yale, the third undefeated Ivy team, routed Columbia, 44-21, in an aerial contest which included eight touchdown passes. The opposing quarterbacks, both of whom were substitutes for injured starters, each set a League passing mark.

Yale's Pete Doherty, replacing the injured Brian Dowling, threw five touchdown passes in the first half to eclipse the previous mark of four touchdown passes shared by Princeton's Ron Landeck (1964 against Brown) and Dartmouth's Bill King (1962 against Columbia).

Sophomore Marty Domres was a surprise starter for Columbia in place of Rick Ballentine, who led the team against Harvard and Princeton during the two previous weeks. Domres responded by tossing three touchdowns and accumulated 326 yards through the air. His passing yardage broke King's old mark of 324 yards.

This Saturday Yale faces Cornell. If the Elis cannot defeat the Big Red -- with or without Dowling, who is still a questionable starter -- then the championship will clearly be between Dartmouth and Harvard. Yale has been an enigma all season. Its offense has powerful running from Calvin Hill, but has lacked consistency against its only two decent opponents, Rutgers and Connecticut. Until last Saturday's game with Columbia (0-4), Yale's defense had looked the most impressive in the League.

Dartmouth's defense permitted Brown the surprisingly high total of 14 points, 14 first downs, and 273 yards in total offense. The Dartmouth offense, however, was more than sufficient, as it gained 426 yards on the ground.

Princeton was blanked by Colgate, 7-0, for its second straight loss. The Tiger defense held slippery Ron Burton to one touchdown, but the offense was embarrassing. For example, Princeton completed 5 of 31 passes for 61 yards and had six attempts intercepted.

Bucknell, having yielded 82 points to Temple two weeks ago, upset Penn, 28-21. It was quite a blow to Ivy prestige. IVY STANDINGS HARVARD  2  0  4  0 YALE  2  0  3  1 DARTMOUTH  2  0  3  1 CORNELL  1  1  3  1 PENN  1  1  2  2 PRINCETON  1  1  2  2 BROWN  0  3  1  3 COLUMBIA  0  3  0  4