Kathy Hartwiger, the 2002 champion, carded a 1-under 71 in the second round. She shared second place at 1-over-par 145 with Thuhashini Selvaratnam (74) and first-round leader Dawn Woodard (77). Woodard had set a new Women's Mid- Amateur single-round scoring record with her 68 Saturday.
Laura Coble took fifth place at plus-2, while Mary Ann Lapointe finished one stroke further back at 3-over-par 147 at Shadow Hawk Golf Club.
'For me, amateur golf is having more control over how much I play and when I play,' said Postillion, who gave up her professional career in 1993. 'That's important because in 1993 I had two little boys. When I had the second boy, that was it for me.'
Mari Miezwa, Lori Planos and Martha Lang shared seventh place at 4-over-par 148. Ellen Port and Carol Semple Thompson, who won this event in 1990 and 1997, were one stroke further back at plus-5.
Corey Weworski, the defending champion, easily made it into match play despite shooting 10-over-par 154 in her two stroke play rounds.
Tina Jones, Barbara Byrnes, Lynn Anderson, Rebecca Gard and Beth Cleckler finished at plus-18 and will play off for the final two spots in match play on Monday morning.
The Women's Mid-Amateur continues with the first round on Monday. The second and third rounds will be played Tuesday, with the quarterfinal and semifinal matches on Wednesday. The Women's Mid-Amateur concludes on Thursday with an 18-hole final.