As we near this rendezvous and prepare to greet Concestor 5—approximately our 1.5-million-greats-grandparent—we cross a momentous (if somewhat arbitrary) boundary. We leave one geological period, the Neogene, to enter an earlier one, the Palaeogene. The next time we do this will be to burst into the Cretaceous world of the dinosaurs. Rendezvous 5 is scheduled at about 25 million years ago, in the Palaeogene. More specifically it is in the Oligocene Epoch of that period, the last stop on our backward journey when the climate and vegetation of the world are recognisably similar to today’
