A Very Short History of the Earth

ChronoZoom – an interactive time scale showing the age of life, the universe and everything (if your computer has the right browser!).
Stratigraphy
ICS – The International Commission on Stratigraphy (the latest geological timescale can be found here).
William Smith and biostratigraphy (part of a University of California Berkeley series on the history of evolutionary thought).
John Phillips – the Time Lord of York (my article for York Mix).
Absolute dating
A quick introduction to radiometric dating (University of California Berkeley).
How to calculate the age of meteorites (or anything else for that matter).
Rock Around The Clock (Daily Telegraph article on the 4.4 billion year-old zircon crystal from Australia). The scientific paper can be found here.
Fossils & Extinction
From soup to cells (Berkeley introduction to the origins of life on Earth).
Solving Darwin’s Dilemma – Precambrian rocks really do contain abundant fossils (report of 2009 study by scientists at Oxford University).
First Life – David Attenborough tackles the origins of life, including the Precambrian fossils found near his childhood home in Leicester.
Mass extinctions (NHM guide to the “Big Five”). If you fancy a “Big Five” walking tour of London, you can follow my not entirely serious guide.
Prehistoric fossil collectors (article from the Geological Society).
How will humans go extinct? (article on BBC News, 24 April 2013).
Hidden Horizons website (Scarborough-based company run by Will Watts, offering Geology & Natural History Education and Events. Look out for information on the upcoming Yorkshire Fossil Festival).