'^ Art. 5.— Matajiro Tokoyama : 



The third and the last ice-age was of a comparatively late 

 date. It was m the Diluvial. During the Tertiary, a period 

 which immediately preceded this age, the climate of Europe and 

 America was very warm, so warm in the beginning that tropical 

 plants grew in Southern England and chelonians and crocodiles 

 inhabited its waters. This great heat, however, gradually 

 diminished as time went on, becoming subtropical in the 

 Miocene and temperate in the Pliocene, the last subdivision 

 of the Tertiary. Within this Pliocene, too, the lowering of 

 temperature still went on from tlie beginning to the end, a sure 

 indication of the approacl) of an ice-age. And this is nowhere 

 more clearly mirrored than on the molluscous animals of the 

 so-called Crag Formation of England which belongs to the above- 

 said Pliocene Epoch. The Mollusca in the lowest division of this 

 Crag, called the Coralline Crag, in spite of an admixture of a few 

 northern or boreal forms, still bears in general the stamp of a very 

 genial climate. But in the Bed Crag, the Crag next above it, the 

 number of boreal forms increases to 10% and in the still higher 

 Norwicli Crag to still more, until at last in the uppermost Crags, — 

 the Chillesfonl and Weghowiie Crags — their number is so great that 

 the fauna may be called really Arctic, and there is even a doubt 

 whether these Crags might not be better classed among the 

 deposits of the ice-age itself. 



With the dawn of the Diluvial Epoch, the whole aspect of 

 Europe and America was changed. Enormous glaciers were 

 moving everywhere. They formed a continuous sheet of ice 

 several thousands of feet in thickness and covering the greater part 

 of the two continents. They looked very much like those now 

 found in the interior of Greenland or on the Antarctic continent. 

 This ice-age, however, was not one continuous age of ice. There 

 were also times in which the ice partly melted and shrunk and 

 the climate became comparatively mild. Such times are called 

 Inter glacials, their number varying in different regions but amount- 

 ing to as many as six, as has been ascertained in America. Thus 

 the ice-age after several fluctuations in the extent of the ice at last 

 disappeared, and in the Alluvi'àTlSF' ]\r6dern EpÔcTr"wT'see*tKe 



