Fossil Plants 



501 



Fig. 311. Map showing the glaciation of the Wisconsin epoch, and the probable distri- 

 bution of the forests when the ice extended farthest south. 



ancestors of our modern conifers. The Cretaceous period is 

 second only to the Carboniferous as a coal-making period. 



The great event of the later Mesozoic era was the appearance 



