154 



THE OPAL SEA 



The 



Venetian 

 lagoons. 



Marsh 

 lands. 



Bars and 

 islands lost 

 in alarms. 



When many of these islands are formed na- 

 ture is disposed to unite them by strands and 

 bridges of sea weed that thicken, knit and hard- 

 en, until finally the whole area turns into a 

 marsh covered with reeds and rushes. Venice 

 with its river Brenta, its lido, and its lagoons, 

 would no doubt have turned to sedge long ago, 

 had it not been for the dredging of the canals 

 and the rise and fall of the one-foot tide. The 

 marsh lands of Albemarle and Pamlico sounds 

 were made possible by such rivers as the Roan- 

 oke stretching sand strips parallel with the 

 shore ; and along the coasts of Maryland, Texas, 

 and Brazil there are millions of acres of marshes 

 formed in this same way. Eventually they be- 

 come coastal plains and are inhabited by man. 



This is all a winning from the sea by the 

 land; and yet it must be admitted that it is 

 not always a permanent accession. At times 

 the sea rises in its might, overwhelms bars, 

 islands, and marshes; and in a single day 

 sets at naught the winning of years. Along 

 the Louisiana shore in the Gulf of Mexico 

 new lands are brought into existence from 

 year to year, but others are being destroyed. 

 Large islands have disappeared from there 

 in recent times leaving only ugly reefs be- 

 hind. Tree stumps that once formed part 



