StrataThe epic stories of our planet's 4. 54 billion year history are written in strata ages old remnants of ancient seafloors, desert dunes, and riverbeds striping landscapes around the world. In this brilliantly original debut work, science writer Laura Poppick decodes strata to lead us on a journey through four global transformations that made our lives on Earth possible: the first accumulations of oxygen in the atmosphere; the deep freezes of "Snowball