TL 2 TYA to 400,001 BC

543 MYA to 248 MYA:

450 MYA:  LC: Elder Thing experiments lead to the first vertebrates, fish, which they permit to evolve.
400 MYA:  LC: The Great Race of Yith, fleeing catastrophe on their homeworld, transmit their minds into a race of cone-shaped creatures on Earth. They drive the Flying Polyps underground and imprison them there. Following that war, they build their first and greatest city, Pnakotus, in modern-day Australia.
370 MYA:  LC: Amphibians arise on Earth. Chaugnar Faugn later creates the Miri Nigri from amphibian flesh, as a servitor race.

350 MYA:  LC: A cataclysm raises numerous new land masses, such as Ponape and R’lyeh. The disaster also destroys several marine Elder Thing cities. Cthulhu and his kin arrive from the star Xoth, and settle on the newly-risen landmasses. The Elder Things war with Cthulhu, but they eventually make peace. Cthulhu is permitted to keep his current surface territories, and the Elder Things keep the rest of the planet.

• The Deep Ones enter the service of Cthulhu, and help build the city of R’lyeh.
• According to legend, the foundation of the underground civilization of K’n-yan dates back to this time.

300 MYA:  LC: A cosmic cataclysm (possibly a certain configuration of the stars, possibly a war with the Elder Gods) occurs, resulting in R’lyeh sinking beneath the waves. Cthulhu is imprisoned within the city. In all likelihood, the other Great Old Ones are imprisoned around the same time.

• Reptiles arise on Earth. Yig is allegedly involved in their creation.

275 MYA:  LC: The Serpent People arise and found the kingdom of Valusia.

250 MYA:  LC: The shoggoths rebel against the Elder Things, but are defeated.

• Atlach-Nacha rules its arachnid Children in the early Mesozoic.

c.250 MYA:  FN: The Cataclysm of the First People.

248 MYA to 65 MYA:

Between 250 and 200 MYA: LC: If the G’harne Fragments are believed, the city of G’harne had been built by the Triassic period. The Fragments themselves also date from this time.
c.225,100,000+ : Titans roam the Earth.
c.225 MYA: Pangaea, World of Warcraft (MMORPG) timeline (>10,000 years long).

225 MYA: LC: The dinosaurs arise and destroy the Serpent People civilization. Those that survive go into hiding.

• The stone tablets that become the Celaeno Fragments are scribed around the middle Triassic. One set of the tablets is eventually taken to the Great Library of Celaeno, on the fourth planet around the star Celaeno.

160 MYA: LC: The mi-go set up a mining operation on Earth. The Elder Things try to battle them in space, but find they have devolved so much that they can no longer do so. The mi-go eventually control much of the northern portion of Earth.

• Some mi-go settle in the land that will become Mu, and worship Ghatanothoa.
• The mi-go also bring with them two objects, later known as the Black Seal of Iraan and the Shining Trapezohedron.

150 MYA: LC: The Great Race of Yith foils a Yekubian invasion attempt. Sometime thereafter, the tablets later known as the Eltdown Shards, which record this event, are buried in modern-day southern England.
100 MYA: LC: Height of the Elder Thing civilization.
65 MYA: Extinction-Level Event (ELE); most of the Dinosaurs are wiped out. How this affected or is connected to the alien races on the planet is unknown.  A few Dinosaurs survive; velociraptors becoming kangaroos, triceratops becoming rhinoceroses, stegosauri becoming komodo dragons, trilobites becoming lobsters, cockroaches, and armadillos, pterodactyls and pteranodons becoming condors, eagles, and flying squirrels, and plesiosauri becoming whales (which became killer whales, cows, and then wolves), apatosauri (brontosauri), seals, and brachiosauri (which became giraffes), as well as pachycephalosauri which became rams, compsognathi which became ostriches, and dilophosauri which became peacocks.

World Trees:

The original trees of Earth and other worlds were miles wide and even taller.

–

65 MYA to 2012 AD:

c.65 MYA: Priest movie timeline, the ELE was from the Priests who ended up nuking their world to stop the new vampire threat after all else failed.

• New and surviving Dinosaurs, including humanoid and sentient ones, populated the Earth.
• The 5th inner planet in the Ra/Sol system, Asteron, is destroyed, becoming the Inner Asteroid Belt.  This event removes Mars’ atmosphere, destroys its civilizations, and deeply scars it.

50 MYA: LC: Another cataclysm strikes Earth. The Flying Polyps escape and take revenge on the Great Race, which sends its greatest minds to bodies on the planet Jupiter. From Jupiter, the Yithians proceed to bodies similar to their Earthly ones on a world orbiting a dark star near Taurus.

• Many Elder Thing cities are also destroyed, including their original settlement in Antarctica. To replace it, a new Antarctic city is constructed.
  A race of pre-human Lemurians build the city of Shamballah in the Great Eastern Desert, probably what is now the Gobi.

Etheric Sub-Period:

c.37 MYA: ME: The Mass Effect timeline begins, never affecting Earth.

Reptoid / Dinoid Sub-Period:

c.20+ MYA: SC: The Xel’naga extra-galactic race seeds many worlds with genetic experiments.
20 MYA: LC: An early race of humans founds the land of Theem’hdra. The civilization soon dies out. Teh Atht, a wizard of the time, leaves behind a manuscript later known as Legends of the Olden Runes.
c.12+ MYA to 4 MYA: Transformers create slaves and civil wars ensue.
6 MYA: LC: A member of a race of “insect-philosophers” which hail from the fourth moon of Jupiter exchanges minds with one of the Great Race of Yith.

5 MYA: LC: The Serpent People city of Yoth flourishes at this time under the guidance of their god, Yig. Their science has progressed to the point that they have created servant species, such as the gyaa-yothn and voormis. However, Yoth is destroyed by Yig when some of the Serpent People turn to the worship of Tsathoggua. A few Yig-worshipping survivors found a new civilization in Hyperborea. Tsathoggua probably journeys to Hyperborea following these events.

• The deep one city of Yatta-uc, beneath modern Lake Titicaca, is in its heyday at this time.

3 MYA: LC: The voormis gain their freedom. They create a kingdom on the surface of Hyperborea, based around the worship of Tsathoggua.

• Rhan-Tegoth comes to Earth from Yuggoth, and comes to dwell in the Arctic. He feeds off sacrifices and worship made by primitive natives, but eventually they forget him and he enters a state of hibernation. Rhan-Tegoth eventually changes into a statue-like form.

Hybornian Sub-Period:

2 MYA: LC: As Elder Thing civilization continues to decline, they retreat to their cities on the southernmost tip of South America and the Antarctic regions.
c.2 MYA: Hyperborea.
1.7 MYA: LC: Ithaqua appears in the northernmost regions of Earth, resulting in the decline of the voormis.
Between 1.6 MYA and 10,000 years ago: LC: The Sussex Fragments date from around this time, the Pleistocene era.

1.5 MYA: LC: Sarkomand, capital city of the men from Leng, is abandoned and falls into ruin when the moon-beasts enslave the Lengites and take them elsewhere.

• The being later known as Dr. Marc Souvate becomes the immortal vehicle for the worshippers of Nodens. He begins a series of jumps forward across long spans of time, heading towards the time when Nodens will return.

1 MYA: LC: The Ice Age is brought about by the combined power of Ithaqua and Aphoom Zhah. The voormis civilization in Hyperborea is destroyed first, replaced by equally ill-fated humans. Some great human sorcerers, including Zon Mezzamalech, live in this short-lived kingdom. The human civilization of Zobna falls next, moving to Lomar in the south and destroying the native cannibal gnophkehs. The much-devolved Elder Things, no longer able to resist intense cold as their ancestors did, develop artificial heating to try to survive.

Lemurian Sub-Period:

c.900,000: Lemuria.
850,000: LC: A king of Lomar is among those that exchange minds with one of the Great Race of Yith.
750,200: LC: The time of the wizard Eibon (the Eibon / Ebon Hand), greatest wizard of Hyperborea. During his life, the worship of Tsathoggua is driven from Hyperborea by priests of Yhoundeh. Eibon disappears at the age of 132 during the Yhoundeh inquisitions, and his assistant Cyron of Varaad correlates several of his sorcerous works into the Book of Eibon. Cyron also writes the Vita Ivonis, an account of Eibon’s life.
750,000: LC: The great polar civilzations finally fall. The Elder Things retreat to deep within the Earth, and the people of Lomar are overwhelmed by the Inuto people. The human civilization in Hyperborea splinters, and its surviving peoples scatter across the planet. A secret brotherhood saves copies of the Book of Eibon from Hyperborea and takes them to mainland Europe. Some voormis begin worshipping Ithaqua, while the rest flee and become known as the Sasquatch and Yeti. The serpent people move to Lemuria and become known as the Dragon Kings.     – Tsathoggua returns to N’kai.

500,000: LC: Homo sapiens, modern humanity, arises. These earliest true humans found the kingdom of Nemedis, and war for a thousand years with the Dragon Kings. The humans win, and the serpent people are driven south.   Dragon Age (game) timeline.

• The exiled serpent people form the second kingdom of Valusia. A few, however, hide instead among the islands of the sea of Neol-Shendis, awaiting their time to rise again.

493,000: LC: Thongor, a barbarian of Lemuria, opposes an attempt at Dragon King takeover with ancient magic. Thongor will later unite Lemuria in his Golden Empire of the Sun.
c.450,000: The first Nibiruan explorer finds Earth.
c.445,000: The Anunnaki (the Biblical Nephilim) of Nibiru land on Earth, establish Eridu (Earth Station 1) to extract gold from the Persian Gulf.