LAKES. 



95 



tops and headlands are now surrounded by peat beds, swamps, and marshy pasture- 

 lands. A careful study of these low-lying tracts shows that they were formerly 

 lakes or navigable gulfs, and here are sometimes still found the remains of boats. 



Fig. 47. — Lakes Wener and AVetter. 

 Scale 1 : 1.500,000. 



Lake bottom sunk 



below the level of 



the Baltic. 



Intermediate 

 depciis. 



20 Miles. 



Above the level 

 of the Baltic. 



The fastnesses were accordingly defended, partly at least, by water, and nearly 

 all the Swedish towns had their origin in such insular strongholds. 



The larger Swedish lakes are themselves an index of the gradual drying up of 

 the land. Formerly continuously united, they formed a strait connecting the 



