106 PHYSICAL GEOGRAPHY. 



sea has made great inroads, sweeping away villages and 

 covering immense tracts of land. The city of Calicut 

 in the East Indies has been quite overflowed by the sea, 

 and ships sail over the place where it once stood. 



Large rivers produce a considerable alteration in the 

 surface of the land, sometimes sweeping away islands at 

 their mouths, and sometimes forming new ones. The 

 soil that is carried into the Gulf of Mexico by the 

 various rivers that flow into it, is so immense, that it is 

 far from impossible but that at some future time it may 

 become innavigable, and ultimately be filled up. It is 

 calculated that 250 millions of tons of matter are annu- 

 ally carried down the river Ganges. The Yellow Sea is 

 said to be rapidly filling up with mud and soil. The land 

 on which Alexandria is built, was not formed 3000 years 

 ago 5 and the cities of Damietta and Rosetta, which less 

 than 1000 years ago were close to the shore, are now 

 two leagues inland. The arms of the Rhone have, in the 

 course of 1800 years, increased three leagues in length, 

 and great additions of land have been made to the west 

 of that river; and numerous places, which less than 1000 

 years ago were situated close to the sea, are now some 

 leagues inland. 



The Lagunes* of Venice are apparently filling up, so 

 that that city will ere long be connected with the main- 

 land. Ravenna was, eighteen centuries ago, situated 

 amongst the lagunes, but it is now a league inland. f 



Downs or hillocks of sand, thrown up by the sea, 

 produce a certain alteration in the Earth's surface. In 

 some places they overwhelm even forests and villages. 

 On the Western coast of France these downs are proceed- 

 ing at a fearful rate, at some places from sixty to seventy 

 feet yearly. On the coast of Scotland, on the Hebrides, 

 and various other places, their effect is very evi- 

 dent. By the sands of the Desert, a great part of 

 Egypt has been inundated, and cities and villages 

 destroyed. 



* The Lagunes are lakes or marshes in which that city is situated. 

 They communicate with the sea, and there are about fifty islands in 

 them. 



f See Cuvier's and Lyell's Treatises. 



