Geological table

Millions of years before present
0-1.7 Quaternary
1.7-65 Tertiary
Modern bivalves and gastropods appear and radiate. Early mammals.
65-135 Cretaceous
Brachiopods decline. Radiation of insect orders associated with flowering plants. Ended in a mass extinction.
135-192 Jurassic
Brachiopods, corals, and marine bivalves common. South America and Africa separate, and Atlantic Ocean is born.
192-230 Triassic
Increase in diversity of marine invertebrates. First flies and sawflies. First dinosaurs.
230-280 Permian
Insect diversification on land and in freshwater, first records of beetles. All continents joined together to form a single landmass. Ended with a mass extinction of 90% marine invertebrates, especially those living in shallow waters, all Trilobites became extinct, and 75% of land species became extinct.
280-345 Carboniferous
Insects colonise land. Giant dragonflies. Corals and brachiopods abundant. British climate is equatorial.

The first record of insects, spiders and mites. Bryozoans and corals abundant. Great Glen and Highland boundary faults formed in what is now Scotland. Ended with a mass extinction which appears to have caused the extinction of 70% of animal species.

405-430 Silurian
Bryozoans, corals and brachiopods abundant. First evidence of scorpions. Europe collides with N. America and Greenland.
430-500 Ordovician
Marine invertebrates abundant. Trilobites declining. Spread of molluscs. Armoured fish. The Ordovician ended in a mass extinction.
500-600 Cambrian
Origin of many invertebrate phyla. Trilobites dominant. Earliest crustaceans. Small molluscs. Britain and Europe in the southern hemisphere.
600-4600 Precambrian
Animal fossil evidence rare; evidence of sponges, cnidaria, ctenophora, and worm burrows c. 670-570 MYBP. Anaerobic bacteria about 3800 MYBP.