Actress June Lockhart, best known for her roles in Lassie and Lost in Space, died at age 100 on Thursday. Lockhart died of natural causes in her Santa Monica, California, home on Thursday, family spokesperson Lyle Gregory said on Saturday. PEOPLE magazine confirmed that the actress died Thursday night around 9:20 p.m. local time. She was with her daughter June Elizabeth and granddaughter Christianna, according to the statement. Born in New York City in 1925, she grew up acting at a young age,