196 FIRST YEAR COURSE IN GENERAL SCIENCE 



the land. The ocean bed does not slope uniformly from 

 the edge of the continent to the deepest water. There are 

 ridges, plateaus, and even mountain peaks rising from the 

 general plain of the ocean bed. 



217. Ocean Temperatures. Except at the shores, where 

 the water is somewhat warmed by contact with rocks and 

 sand, the ocean is warmed by absorbing heat from the sun. 

 The heat penetrates, however, only a few feet below the 



FIG. 102. TEMPERATURE IN AN ENCLOSED SEA BASIN 



Water enters the Gulf of Mexico from the ocean at the strait of Yuca- 

 tan, where the water is about 1,000 fathoms deep. 1. What is the ocean 

 temperature at that depth? 2. What is the greatest depth of the gulf? 



3. What is the temperature of the coldest water that enters the gulf? 



4. What is the temperature at the bottom of the gulf? Why is it not so 

 cold as that at the bottom of the ocean? 



surface. The temperature of the surface water is highest 

 (ranging from 80 to 85 F.) in the tropics, where the sun 

 is directly overhead somewhere every day in the year. At 

 the bottom, the temperature of the ocean the world over is 

 at about freezing point. 



If a strait connecting a partly inclosed body of water with 

 the ocean is shallower than the ocean, only the warm sur- 



