356 E. C. ANDREWS, 
The general lack of relief in the Cretaceous continents 
appears to have been due to the action of long continued 
erosion, while the great epicontinental seas were caused 
by a general rise of the ocean levels, suggestive of a spill-. 
ing over of the oceans basins on to the continents. North 
America was separated thus into two portions by a long 
and wide sea running north and south from the Gulf of 
Mexico to the Arctic Ocean. A great Mediterranean sea — 
appears to have extended from the Mexican Gulf clean 
across South Europe, and Northern Africa, to the eastern 
portion of the Himalaya. Australia also was almost com- 
pletely separated in two portions’ by a long and wide sea. 
extending southwards from the Gulf of Carpentaria. The 
continents of Asia and Africa also appear to have been 
isolated towards the close of the Cretaceous by the general 
rise of the water in the ocean basins. 
A study of the fossil animals and plants, as also the 
sediments of the periods, indicates that the Cretaceous. 
was a period of genial and moist climate, but that the 
latter became differentiated somewhat near its close. 
The Kocene, or Harlier Tertiary, was ushered in by the 
formation of mountain chains in regions outside of Australia 
and Africa generally. The epicontinental seas were 
drained, in great measure, but the great Mediterranean 
sea already mentioned was a distinctive feature, as was 
also an offshoot thence from the Caspian Sea region estab- 
lishing marine communication with the Arctic Ocean. 
The climate was generally mild and moist extending far to 
the north and south of the tropics. 
Since that date the climate of the globe has been under- 
going distinct, but oscillatory, differentiation throughout 
the Miocene and Pliocene Periods culminating in the 
1 (2) p. 526-538. 
