The warm jungles of ancient France

Chemical analyses of amber excavated near Paris suggest that France was covered with a dense tropical forest about 55 million years ago.

ANCIENT SAP. Amber from France’s Oise River basin contains quesnoin, a substance whose precursor is made in abundance by a tree found today only in the Amazon Basin. A. Nel/National Museum of Natural History, Paris

Amber is a form of fossilized tree sap.