Jurassic

The Jurassic was a period in early Earth history in which the dinosaurs thrived.

The red leeches, known as Crimson Horror, were a species supposed to live in the Jurassic era. The Eleventh Doctor expressed intention to take back to the Jurassic era a specimen who was infesting Sweetville. (TV: The Crimson Horror)

According to the Fourth Doctor and his geologic evaluations, the hand of the Kastrian Eldrad landed on Earth during this age. (TV: The Hand of Fear)

A Concorde designated Golf Victor Foxtrot mysteriously disappeared from Heathrow Airport in 1982, inadvertently travelling down a time corridor to the Jurassic period. The Fifth Doctor used a second Concorde, designation Golf Alpha Charlie, to investigate the first Concorde's disappearance and followed it through the time corridor. At one point the Master's TARDIS was temporarily disguised as Concorde Golf Victor Foxtrot, and materialised around it. Eventually, Concorde Golf Alpha Charlie was repaired using parts taken from Concorde Golf Victor Foxtrot and returned to 1982, leaving Concorde Golf Victor Foxtrot buried in the past. By 1982 Concorde Golf Victor Foxtrot was fossilised and buried beneath Heathrow. (TV: Time-Flight)

Professor Saurian tried to change Earth history using a 'roll-back machine' that saw Times Square in New York being evacuated as the city was overrun by dinosaurs from the Jurassic. The Eleventh Doctor defeated Saurian this time by resetting his machine via "reversing the polarity of the neutron flow". Saurian was taken along with his machine and the dinosaurs back to the Jurassic Age. (COMIC: Dinosaurs in New York!)

Other references
When the Seventh Doctor and Ace encountered dinosaurs after landing on Earth, the Doctor believed they had landed in the Jurassic period, but had infact arrived in an alternate timeline where Silurians ruled over humanity. (PROSE: Blood Heat)

The Sontaran Strax defined "Jurassic emergency" the incongrous appearance of a Tyrannosaurus rex in London, during the Victorian era. (TV: Deep Breath)