A River Thames walk to a great pub: The Oiler London Docklands

Fossils and geology stretching back millions of years are revealed on this fascinating route by river mudflats and ancient woods

Near the start of his book Otherlands, palaeobiologist Thomas Halliday sketches the London landscape 50 million years ago: swampy forest and tropical waters filled with crocodiles, sea turtles, mangroves and huge lily pads. Otherlands is a compelling recreation of vanished ecosystems and the ways in which they can help predict possible outcomes of the changing climate. I meet the author for a riverside walk to explore modern London and its traces of past landscapes, and to look at what the future might hold.

My temporal adventure starts, before we meet, in Lesnes Abbey Woods, easy to reach on the new Elizabeth Line. With its 12th-century abbey ruins, bronze age tumulus and ancient mossy forests, walking in this area has always felt like time-travelling. Squirrels and squawking green parakeets flash through the trees as I follow signs to a fossil bed, a sandy area where anyone can come and search for 50-million-year-old shells and sharks’ teeth. A wooden coryphodon, an extinct semi-aquatic mammal whose remains have been found here, guards the entrance.