362 THE HISTORY OF CREATION. 



hy a strait, but they have now for the most part sunk 

 below the level of the sea. Wallace, solely on the ground of 

 his accurate chorological observations, has been able in the 

 most acute manner to determine the position of this former 

 strait, the south end of which passes between Balij and 

 Lombok. 



Thus, ever since liquid water existed on the earth, the 

 boundaries of water and land have eternally changed, and 

 we may assert that the outlines of continents and islands 

 have never remained for an hour, nay, even for a minute, 

 exactly the same. For the waves eternally and perpetually 

 break on the edge of the coast, and whatever the land in 

 these places loses in extent, it gains in other places by the 

 accumulation of mud, which condenses into solid stone and 

 ao-ain rises above the level of the sea as new land. Nothing^ 

 can be more erroneous than the idea of a firm and 

 unchangeable outline of our continents, such as is im- 

 pressed upon us in early youth by defective lessons on 

 geography, which are devoid of a geological basis. 



I need hardly draw attention to the fact that these 

 o-eoloo-ical chano-es of the earth's surface have ever been ex- 

 ceedingly important to the migrations of organisms, and 

 C(jnsequently to their Chorology. From them we learn to 

 understand how it is that the same or nearly related species of 

 animals and plants can occur on different islands, although 

 they could not have passed through the water separating 

 them, and how other species living in fresh water can inhabit 

 different enclosed water-basins, although they could not have 

 crossed the land lying between them. These islands were 

 formerly mountain peaks of a connected continent, and 

 these lakes were once directly connected with one another 



