Children's illustrated science book about earth history, in which each age (formation of the solar system, age of dinosaurs, building Egypt's pyramids, etc.) is presented as a scene on stage in a play, with curtains to the sides. Last scene is at a typical house in the present day. Might have been printed in the 1930s or 1940s, was available in a grade-school library in the late 1970s.
Well, I found it. The book is “Life Story” by Virginia Lee Burton, originally published in 1962. It was Burton’s last book; she was also known for “Mike Mulligan and His Steam Shovel,” “Katy and the Big Snow,” and “The Little House.” An updated version of “Life Story” was published in 2009.