Several million years ago, at a time when dinosaurs walked the earth, a flying reptile – a pterosaur – came in for a landing. As it approached, it used its powerful wings to slow itself down and hit the ground feet first. It took a short hopping step before landing a second time. On solid ground, it leant forward, put its arms down and walked away on all fours.
The landing made quite an impression on the underlying limestone mud and in the following millennia, the creature’s tracks became fossilised. Now, they have been unearthed by Jean-Michel Mazin from the University of Lyon at a site near Crayssac in southwestern France.
The area is home to at least 30 sets of pterosaur tracks, which have earned it the nickname of Pterosaur Beach. Some of these tracks have confirmed that some pterosaurs walked on four legs while land-bound, in the manner of many modern bats. But one bizarre set stood out to Mazin – they simply didn’t fit the typical walking gait of the French pterosaurs. The most plausible explanation is that they preserved a landing, and they’re the first set of fossils that have done so.
Hundreds of thousands of years ago, one of the largest floods in Earth’s history turned us into an island and changed the course of our history. Britain was not always isolated from our continental neighbours. In the Pleistocene era, we were linked to France by a land ridge called the Weald-Artois anticline that extended from Dover, across what are now the Dover Straits.
This ridge of chalk separated the North Sea on one side from the English Channel on the other. For Britain to become an island, something had to have breached the ridge.
Now, Sanjeev Gupta and colleagues from Imperial College London have found firm evidence that a huge ‘megaflood‘ was responsible. They analysed a hidden series of massive valleys on the floor of the English Channel – vast gouges of bedrock 50 metres deep and tens of kilometres wide.
These valleys were first noticed by geologists in the 1970s but until now, no one really knew what caused them. Gupta decided to find out with the help of some modern technology. He used high-resolution sonar to create a contour map of the Channel floor, and found that this hidden world was remarkably well preserved.
He saw a clear picture of the huge, linear valleys, branching out in a westerly direction. In and among the valleys lay long ridges and grooves running parallel to the channel, V-shaped scours that taper upstream, and streamlined underwater islands up to 10km long.