Jurassic

[p 108] Like the Forest Marble Beds in the Middle Jurassic, the Purbeck Beds of the Upper Jurassic are deltaic or estuarine in origin, so as well as mammals they contain small, presumably freshwater, crocodiles and the first indisputable lizards.

[p 109] This is less surprising if it is recalled that in the Upper Jurassic, Europe and North America were joined to form Laurasia and the Atlantic Ocean still had to be formed …