236 ELEMENTARY GEOLOGY 
was warmed in the tropical regions. It then crosses 
the Atlantic, a part extending into the Arctic Ocean, 
between Iceland and the European coast, the remainder 
returning southward along the shores of Europe, where 
it again enters the whirl. From the cold polar region 
there are return currents of frigid waters; but these are 
less distinct than the warm equatorial currents. 
These great movements of the water, which are 
found in every ocean, transport quantities of heat or 
cold, so that they serve to modify in marked degree, the 
climates of the ocean and the coasts. For instance, the 
Bermudas, and even the British Islands, have their 
temperature raised by the warm Gulf Stream, while 
a cold Labrador current chills the coasts of Nova 
Scotia and northern New England, which lie in the 
same latitude as central Europe. This current is one 
of the means of transportation of Arctic ice into tem- 
perate latitudes. 
Since to a great extent the development of the 
animals of sea and land is influenced. by temperature, 
these movements of the ocean water are of much im- 
portance to them. Any change in the course of the 
flow will produce very decided effects upon life. For 
instance, if the Gulf Stream did not bathe the 
European lands, parts of northern Europe would be 
rendered uninhabitable. 
There is no reason for believing that the ocean currents 
