Historical Geology Understanding Our Planet\'s Past

crocodiles, and primitive mammals. The dinosaurs included herbivorous

hadrosaurs and triceratops along with the carnosaurs that preyed on them.

Toward the end of the Cretaceous, North America and Europe were no

longer in contact, except for a land bridge that spanned Greenland to the

north. The strait between Alaska and Asia narrowed, creating the practically

landlocked Arctic Ocean.The South Atlantic continued to widen, with South

America and Africa separated by more than 1,500 miles of ocean. Africa

moved northward and began to close the Tethys Sea, leaving behind Antarc-

tica,which was still joined to Australia.

As Antarctica and Australia continued to move eastward, a rift developed

that eventually separated them.After rifting apart,Australia moved into the lower

latitudes, while Antarctica drifted into the southern polar region and accumu-

lated a massive ice sheet. Meanwhile, the northward-drifting subcontinent of

India narrowed the gap between itself and southern Asia at a rate of about 2

inches per year. During its journey after the breakup with Gondwana, no known

mammals appear to have existed in India until after its collision with Eurasia.

Figure 168Distribution
of continents around the
Tethys Sea during the late
Cretaceous.

Historical Geology

NORTH

AMERICA

EUROPE

Tethys Sea

AFRICA

India

AUSTRALIA

ANTARCTICA

SOUTH

AMERICA