208 THE GEOLOGICAL HISTORY OF PLANTS. 



America, and is also said to be found in Japan, Australia, 

 and India, a width of distribution appropriate to so old 

 a type (Fig. 76). 



In so far as vegetable life is concerned, the transition 

 from the Upper Cretaceous to the Tertiary or Kainozoic 

 is easy, though in many parts of the world, and more 

 especially in western Europe, there is a great gap in the 

 deposits between the upper Chalk and the lowest Eocene. 

 With reference to fossil plants, Schimper recognises in 

 the Kainozoic, beginning with the oldest, five formations 

 Palseocene, Eocene, Oligocene, Miocene, and Pliocene. 

 Throughout these a flora, similar to that of the Creta- 

 ceous on the one hand and the modern on the other, 

 though with important local peculiarities, extends. There 

 is evidence, however, of a gradual refrigeration, so that 

 in the Pliocene the climates of the northern hemisphere 

 were not markedly different from their present character. 



In the first instance an important error was com- 

 mitted by palaeobotanists, in referring to the Miocene 

 many deposits really belonging to the Eocene. This 

 arose from the early study of the rich plant-bearing 

 Miocene beds of Switzerland, and from the similarity of 

 the flora all the way from the Middle Cretaceous to the 

 later Tertiary. The differences are now being worked 

 out, and we owe to Mr. Starkie Gardner the credit of 

 pointing these out in England, and to the Geological 

 Survey of Canada that of collecting the material for 

 exhibiting them in the more northern part of America. 



In the great interior plain of America there rests 

 on the Cretaceous a series of clays and sandstones with 

 beds of lignite, some of them eighteen feet in thickness. 

 This was formerly known as the lignitic or lignite Ter- 

 tiary, but more recently as the Laramie series. These 

 beds were deposited in fresh or brackish water, in an 

 internal sea or group of lakes and swamps, when the 

 continent was lower than at present. They have been 



