Vaughan went on to make 88, his highest score of the season, and then the left-handed pair of David Byas and Michael Bevan continued their fine form.
They put on 180 in 51 overs before Bevan was out for 89 with 16 fours just before the close. Byas remains unbeaten on 113 from 196 balls with one more boundary than Bevan as Yorkshire finished on 379 for 3.
There was more toil in the sun for little reward for the bowlers at Canterbury. Surrey's Darren Bicknell and Graham Thorpe hit their second Championship hundreds of the season as the visitors totalled 345 for 2.
The second-wicket pair put on 260 - and all this after Bicknell gave a chance off the first ball of the day, his edge just eluding Graham Cowdrey's hand at second slip. He eventually fell to Steve Herzberg for 146. Thorpe continues today on 152.
In the second Under-19 Test at Worcester, England reduced South Africa from a comfortable 143 for 1 to 200 for 7. It took the efforts of their captain Neil McKenzie (77no) and Pierre Joubert (37no) to steady their innings with an unbroken stand of 80.
Worcestershire's Vikram Solanki started the collapse with two wickets in his first over and Middlesex's left-arm spinner Umer Rashid took three wickets in successive overs.Reuse content