THE EUROPEAN SEAS. 



201 



The Black Sea, from east to west, is about 7 00 

 miles in length, with a breadth of 300, giving an 

 area of 170,000 square miles; its depth in places 

 is nearly equal to that of the Mediterranean. Be- 

 yond this again is another expanse of water — the 

 Sea of Azof, with an area of 14,000 square miles; 

 this is a shallow sea. 



Into these two depressions, which together exceed 

 the area of the British Islands, some of the largest 

 rivers in Europe discharge themselves, such as the 

 Danube, the Dnjepr, the Dnjestr, the Bug, and 

 the Don. To these might be added an almost 

 endless list of minor rivers, many of which far ex- 

 ceed the volume of the largest British streams. 



Some of the rivers which discharge into the 

 Black Sea take their rise in high latitudes, in dis- 

 tricts annually covered with snow. These rivers also 

 are annually frozen. Again, the winter temperature 

 of the northern shores of this sea is such that 

 coast ice forms there, as also in the Sea of Azof ; 

 and hence the waters of the Black Sea are much 

 colder than those of the rest of the marine province 

 to which it belongs.lt is to the combi ned influence 

 of composition and temperature that the great dif- 

 ference in the assemblage of animals in the Medi- 

 terranean and Black seas must be attributed. The 

 Black Sea is the great ultimate estuary of the rivers 

 which drain one-half of the European area. 



The proportion of Baltic Testacea to those of the 

 Celtic Atlantic region is as fifteen to three hundred. 



