THE ROMANCE OF OUR TREES 



historic times the Cedar forests occupied much lower 

 levels and were continuous. He adduces geological 

 evidence to prove that vast changes took place in 

 the Mediterranean basin during Tertiary times, and 

 shows that in the warm period which followed the 

 glacial epoch the vegetation of the lower levels 

 was forced to seek colder situations and so migrated 

 northward and up the mountains. This would 

 bring about the geographical isolations of the Cedar 

 and the differences now apparent between the four 

 species are mere variations fixed and accentuated 

 through time. 



Now the Cedars though not so ancient as the 

 Ginkgo are an old type of tree-life. Fossil remains 

 of the ancestors of the present race have been found 

 in the Lower Greensand of England around Maid- 

 stone and Folkestone in Kent, and at Shanklin in 

 the Isle of Wight. This Lower Greensand underlies 

 Chalk and belongs to the Cretaceous or Chalk Age, a 

 geological era remarkably prolific in animal life. In 

 this period birds very probably first appeared, the 

 Terrible Lizards of the Reptilian Age disappeared, 

 but a race of extraordinary, serpent-like Reptiles 

 (Mosasaurus) flourished. These were long, snake- 

 like animals with pointed teeth, and were furnished 

 with swimming paddles and a long and powerful tail. 

 One species of these astonishing creatures of which 

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