Where's Emily by Carolyn Wells

On the eve of her marriage to Rodney Sayre, Emily Duane disappears. She had left her Hillside Park home to visit the hospital but never arrived. Foul play is feared when Jim Pennington reports his wife Pauline, Emily’s best friend, also missing. Pennington says he left his wife at the ravine a short distance from Emily’s home. When he returned, she had vanished. Then Polly’s body is found in the ravine...but where is Emily? Fleming Stone investivates!