Different Era's

Eras	Age In millions of years	Periods	Geographical Conditions
Azoic Proterozoic	4700 3000	Pre-Cambrian Origin of the earth	From the formation of the earth: barren landscapes, torrential rain, several ice ages, the beginning of life.
Palaeozoic (Ancient Life)	570	Cambrian After Cambria, the roman name for Wales	Shallow seas, advancing and retreating. Volcanoes in Wales and Europe generally. Warm Climate
	500	Ordovician After Ordovices, a Celtic tribe	Seas advance and retreat. Volcanic activity, warm climate. First animals with backbones
	440	Silurian After Silures, a Celtic tribe	Fluctuations of sea level. First evidence of new mountains being formed. First land plants
	395	Devonian After the English count of Devon	Mountain building in north, west Europe and North America. Plants become abundant as do fishes. First amphibians
	345	Carboniferous From the existence of coal seams	Shallow seas and swamps. Giant insects and first replies, Trees grew to thirsty meters in height
	280	Permian After the Russian province of perm	Lofty mountains formed such as the Appalachians in the United States. Deserts in northern hemisphere.
Mesozoic (Middle Life)	225	Triassic After three fold division in Germany	Deserts, salt lakes and shallow seas. First ichthyosaurs and mammals.
	195	Jurassic After Jura mountains on French-Swiss frontier	Sea invades land. Continents possibly begin to divide. Reptiles evolve. Dinosaurs roam the land.
	136	Cretaceous From the Latin word for chalk	Swamps and deltas. Mountain building, Rocky Mountains and the Andes. Insects and flowering plants spread.
Cainozoic (Recent Life)	65	Palaeocene Meaning the earliest of recent forms of life	Advance of sea. Warm Climate. Dinosaurs have become extinct along with many other reptiles.
	54	Eocene Meaning the dawn of recent life	Further mountain building, Lava outpourings in Scotland, Ireland and Arctic. Warm beginning of modern mammals.
	38	Oligocene Meaning few recent forms of life	Mountain building of Alps commenced warm grasslands. Spread of mammals
	26	Miocene Meaning less recent forms of life	Formation of Alps and Himalayas. Primitive anthropoid ape.
	7	Pliocene Meaning more recent life	Present day climate. Lands appear almost as today. Man like apes continues to develop.
	2	Pleistocene Meaning most recent life	Ice sheets advance and retreat over Europe, North America and Antarctica. Development of primitive man.
	50000 BC	Holocene Meaning wholly recent life	Ice retreats. Sea level rises. Forests develop. Man becomes dominant over his environment.