A History of the Whoniverse
CITY OF DEATH
At this time, Scaroth, the last survivor of an advanced humanoid race called the Jagorath who had wiped themselves out in a huge war, crashed on primeval Earth. Attempting to take his ship to power three, warp thrust, he got too close to Earth's surface and his spaceship exploded over what would become the Atlantic Ocean. This somehow split him into twelve segments, which would later appear at various points in human history. [The interference of the last of these segments, the fourth Doctor, Romana, and a 1979 detective called Duggan may be responsible for this effect.] The explosion acted as a catalyst for the primeval soup, which had formed to become simple life.
Although the date is given by Scaroth and others as 400,000,000 BC, current evolutionary theory claims that life on Earth began c.3,500,000,000 BC and it had already begun by Venusian Lullaby. Hence, either the date or its connection to the creation of life on Earth is wrong.
c. 3,000,000,000 BC
For three million years before this time, there had been a thriving civilisation on Venus. The Venusians were allergic to all metals except gold, platinum, and titanium. Despite this, their civilisation was highly developed, more so than those of many races without such weaknesses. But now Venus was dying. Most of its plant and animal life had gone and the majority of Venusians had accepted their fate. In some areas, Death Inspectors killed Venusians who had outlived their usefulness. A small number of Venusians tried to escape their fate. Thus such groups as the Magneteers, the Below the Sun Believers, the Magnetologists, the Water Breathers, the Rocketeers, the Cave Makers and the Volcano Makers had sprung up.
Following the death of Jofghil Dharkhig, Presidor of the Night Council of Bikugih, a vampiric race called the Sou(ou)shi offered the Venusians a way out in their vast spaceship. When the Venusians found out that the Sou(ou)shi just wanted to consume their race, the Volcano people destroyed the Sou(ou)shi ship, causing a dust cloud that prolonged Venusian civilisation for another hundred generations. The Sou(ou)shi escaped to primeval Earth where they waited for life to evolve into a sentient form that they could use.
The Doctor approximates the date as 3 billion BC on page 18 and 3.5 billion BC on page 159.
[Some of] the Great Old Ones visit Veltroch, and leave behind ancient carvings. There are no other records of their influence on the planet.
White Darkness. The carvings are said to be at least 3 billion years old (page 90).
c. 1,000,000,000 BC
Around this time, the Nestene Consciousness began their conquest of other worlds. Also around this time, the last seas dried up on Androzani Major.
One billion years before Spearhead from Space and The Caves of Androzani respectively.
c. 500,000,000 BC
A spacecraft visits Earth, leaving trace elements of warp-drive radiation.
This was 500 million years before Invasion of the Cat-People page 3 (39,780 BC), it may be a reference to Scaroth's ship in City of Death. On the other hand, page 2 suggests that it's only 1,000,000 years after Adric's crash in Earthshock (65 million BC).
c. 352,000,000 BC
The descendants of Lungfish evolve into Ichthyostega, the first true amphibians.
According to the Doctor's dream on Transit page 1, this happened two million years early. Evolutionary theory tells us this was about 350 million years ago.
c. 200,000,000 BC
At this point, all of Earth's landmasses are part of a super-continent called Pangaea.
This is shown on a globe in The Silurians, and dated by evolutionary/geological theory.
c. 150,000,000 BC
On the planet Kastria, the scientist Eldrad created barriers to keep out the solar winds that had ravaged the planet. He also devised a silicon-based form for the Kastrians and built machines that would replenish both the planet and its atmosphere. Eldrad then attempted to seize control and go on a galactic war of conquest. The rest of the population declined to co-operate and destroyed the barriers, sending
him into space in an obliteration module. The capsule was prematurely detonated at nineteen spans, due to a computer fault. Against odds of one in three million, Eldrad survived. His hand eventually reached Earth and became buried in a Jurassic stratum of Blackstone Dolomite.
According to the Doctor, this happened 150,000,000 years before The Hand of Fear.
At some time between 195 and 136 million BC, Whitaker kidnapped some dinosaurs and took them to 1974. A Plesiosaurus (evolutionary theory thinks the species became extinct around 130 million BC) was kidnapped and placed in a miniscope. In the late Cretaceous (140-65,000,000 BC) the Rani obtained some Tyrannosaur embryos. Whitaker's time scoop collected some dinosaurs from this time period as well. The deinonychus (120 million BC) existed in what would become California.
The time scoop is from Invasion of the Dinosaurs. The miniscope is from Carnival of Monsters episode 1. The Rani's activities are mentioned in Mark of the Rani. The deinonychus is mentioned in Short Trips and Side Steps: A Town Called Eternity.
c. 140,000,000 BC
The Xeraphin's planet is devastated by the Vardon-Kosnax war, and they flee to Earth. They are poisoned by radiation sickness, and form themselves into a gestalt entity to regenerate. This process is interrupted by the intervention of two Time Lords.
The date is given by the Doctor, who correctly states that it's the Jurassic era. He also claims that they can't be far off the Pleistocene era (1.8 million-10,000 BC).
c. 85,000,000 BC
The Ornithomimus, Triceratops, and Tyrannosaurus Rex are alive at this time
In Blood Heat (page 21), the Doctor claims the Ornithomimus comes from the Cretaceous era (97.5 million BC to 66.4 million BC). The other species and the specific date are mentioned in a sign at Cheddar Gorge on page 45. This sign also mentions the Brontosaurus, which we now know never existed (it was "discovered" when a palaeontologist put the wrong head on an Apatosaurus). Because the sign dates from the early-1970s or before, which was before they discovered the mistake, I assume that the mistake was made in the same way in the Whoniverse.
c. 65,000,000 BC
A spacecraft from 2526 AD exploded in Earth's atmosphere, killing most of the Dinosaurs and a great deal of other life. This was watched by the Timewyrm. It released a massive dust cloud, and lowered the temperature.
The date is given by the Doctor. Further details are given in Timewyrm: Revelation (page 113), and Transit (pages 1-2). This does not, however, kill all the Dinosaurs off. Timewyrm: Revelation states that the arrival of the moon finished the job. This explains why the Earth Reptiles had dinosaur pets in The Silurians and Blood Heat. This is referred to as the K/T impact by the Master in Face of the Enemy (page 215) although Ian is unfamiliar with the term.