322 THE BEAUTIES OF NATURE CHAP. 
back to the time when that great sheet of 
fresh water was in connection with the Arctic 
Ocean, so there is in the character of the 
Fauna of the Italian lakes, and especially the 
presence of a Crab in the Lake of Garda, 
some confirmation of such an idea. Further 
evidence, however, is necessary before these 
interesting questions can be definitely an- 
swered. 
Lastly, some lakes and inland seas seem to 
be due to even greater cosmical causes. Thus 
a line inclined ten degrees to the pole be- 
ginning at Gibraltar would pass through 
a great chain of inland waters—the Medi- » 
terranean, Black Sea, Caspian, Aral, Baikal, 
and back again through the great American 
+ Jakes: 
But though many causes have contributed 
to the original formation and direction of | 
Valleys, their present condition is mainly due 
to the action of water. When we contemplate 
such a valley, for example, as that which is 
called par excellence the “ Valais,” we can at 
first hardly bring ourselves to realise this; 
but we can trace up valleys, from the little 
