Age of the Dinosaurs
The Age of the Dinoosaur was a lengthy period in Earth's histry, long prior to the arising of humans. According to the Fourth Doctor, it was also known as the Age of the Monsters. (PROSE: The Doctor Who Dinosaur Book) They lived on Earth for around 165 million years before becoming extinct. (PROSE: A History of Humankind)
According to some accounts, the Silurian civilisation flourished during the time when the dinosaurs walked the Earth, (TV: Dinosaurs on a Spaceship, Deep Breath) although other accounts placed them either well before the Dinosaurs' day, in the eponymous Silurian era, (TV: Doctor Who and the Silurians) or much later in Earth's history, (TV: The Sea Devils) with the dinosaurs familiar to the Silurians having been creatues artificially brought back from extinction by the Silurians' brilliant geneticists. (PROSE: Blood Heat)
The Fourth Doctor once travelled throughout the Age of the Dinosaurs at speed with a human companion to give them an overview of the majesty and variety of dinosaurs and similar reptiles. (PROSE: The Doctor Who Dinosaur Book)