Huge mega-rafts carried dinosaur-era animals on round-the-world trips

Huge floating logs carried communities of animals on round-the-world trips during the dinosaur era. The mega-rafts gave marine animals a way to travel without passing through deadly low-oxygen zones.

We have long known of preserved logs up to 14 metres long from the Jurassic period 200 to 145 million years ago. The logs are covered in crinoids, an animal related to starfish that has a central body with many long feathery arms. The logs also carry oysters.

Initial studies in the 1960s suggested that these logs were…