Roberta Laidlaw Forbes, 67, the former wife of the late publisher Malcolm Forbes, died Wednesday of lung cancer at her home in Bedminster, N.J. She was married to Forbes for 39 years before the couple divorced in 1985. He died two years ago at age 70.

Lucy M. Lewis, an influential American Indian potter, died March 12 in Acoma Pueblo, N.M. after a long illness. Mrs. Lewis' birth date was never recorded, but she was born before the turn of the century. Her works have been shown around the world and are included in collections at the Smithsonian Institution.